Dinocyst Biostratigraphy of the Lower Cretaceous in North Siberia …cretaceous.ru/files/pub/people/pestchevitskaya/07-dino... · 2018-01-17 · Novosibirsk, Russia Received June

577

ISSN 0869-5938, Stratigraphy and Geological Correlation, 2007, Vol. 15, No. 6, pp. 577–609. © Pleiades Publishing, Ltd., 2007.Original Russian Text © E.B. Pestchevitskaya, 2007, published in Stratigrafiya. Geologicheskaya Korrelyatsiya, 2007, Vol. 15, No. 6, pp. 28–61.

INTRODUCTION

Organic-walled microphytoplankton is widespreadin the Lower Cretaceous deposits of western and cen-tral Siberia, as experts in palynology noted repeatedly.This group of very diverse microfossils includesdinoflagellate cysts (dinocysts), acritarchs, Chloro-phyceae and Zignemataceae remains. A considerablestratigraphic potential of dinocysts well studied in tax-onomic aspect is confirmed by a great amount of dataon their stratigraphic and lateral distribution in Europe,Asia and America. At present, dinocysts are broadly inuse for a high-resolution subdivision of the Lower Cre-taceous in West Europe and Canada. In contrast, spe-cialized investigations of dinocysts from the LowerCretaceous of Siberia with parallel assessment of strati-graphic value of separate taxa are comparatively rare.Hence, new data in this sphere of biostratigraphy are ofa great interest.

Presented in this work are the results of palynologi-cal study of the Lower Cretaceous sections in the northof western and central Siberia (Fig. 1) and the analysisof stratigraphic distribution of Early Cretaceousdinocysts in northern areas of Eurasia. The results ofpalynological analysis are used to subdivide in detailthe respective North Siberian sections, to establish gen-eral succession of the Lower Cretaceous dinocystszones, and to define correlation levels recognizable farbeyond Siberia in northern Europe, Greenland andCanada.

Natural outcrops of the Lower Cretaceous in theKhatanga depression are of special importance forelaboration of the Siberian dinocyst scale. The respec-tive sections bearing diverse paleontological remainsfacilitated construction of the Boreal standard zona-tions (Zakharov et al., 1997), and the distinguishedpalynostratigraphic units have been correlated withzonal subdivisions of macro- and microfauna. In theBerriasian, Valanginian and Hauterivian intervals ofsections in the Nordvik Peninsula, the Anabar Bay east-ern coast, their stratigraphic position has been con-trolled by data on ammonites, belemnites, bivalves andforaminifers (

The reference Section…

, 1981; Bogo-molov et al., 1983; Zakharov et al., 1983; Bogomolov,1989; Shenfil’, 1992; Marinov and Zakharov, 2001;Nikitenko et al., 2004). Foraminifers and ammoniteshave been also identified in borehole section Severo-Vologochanskaya 18 (Nikitenko et al., 2004), whileammonites, foraminifers and bivalves have beendetected in the lower Valanginian of borehole sectionRomanovskaya 140 (Zakharov et al., 1999). In bore-hole section Gorshkovskaya 1017, age of deposits isdefined by palynological data only, as faunal remainshave not been found here.

MATERIAL AND INVESTIGATION METHODS

This study is based on palynological analysis of theLower Cretaceous marine sections extending oneanother in vertical direction with partial overlap (Fig. 2).In total, the analyzed sections span stratigraphic inter-

Dinocyst Biostratigraphy of the Lower Cretaceousin North Siberia

E. B. Pestchevitskaya

Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia

Received June 28, 2006; in final form, March 6, 2007

Abstract

—The described scheme of the Lower Cretaceous (Berriasian–Barremian) stratigraphic subdivisionsis elaborated based on palynological study of sections in the Khatanga depression, Ust-Yenisei region, Pur–Tazinterfluve, and around the Ob River latitudinal segment, the North Siberia. Stratigraphic distribution of micro-phytoplankton studied in detail is used to distinguish 10 biostratigraphic units in the rank of dinocysts zones.Stratigraphic position of the zones is determined with confidence using data on the Lower Cretaceous referencesections in the Khatanga depression, which were principal ones by constructing the Boreal standard zonation.In majority, boundaries of the dinocysts beds are of a high correlation potential and can be regarded as reliablestratigraphic markers, as they are recognizable not only in Siberia, but also in northern Europe and America.

DOI:

10.1134/S0869593807060020

Key words

: Lower Cretaceous, stratigraphy, dinocysts, Siberia, correlation, northern regions of Eurasia andAmerica.

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PESTCHEVITSKAYA

val from the Berriasian up to the lower Barremianinclusive. In the Khatanga depression, the most com-plete succession has been studied in sections of theNordvik Peninsula, where the Berriasian and Valangin-ian deposits are represented by gray clays and aleurites(Fig. 2). Sands prevailing in the Hauterivian Stage areintercalated with subordinate aleurite and clay interlay-ers of lesser thickness. In section of the Anabar Bayeastern coast, there is exposed only a lower part of theValanginian. Silty calcareous clays prevailing in thissection are intercalated with sandstone interlayers. Inthe Ust-Yenisei region, the upper Berriasian–lowerHauterivian succession studied in borehole sectionSevero-Vologochanskaya 18 is composed of gray aleu-rites with thin clay and sand interlayers (Fig. 3), andthere is a general tendency of sandy material increaseupward in the section. In the northwestern Siberia, theLower Cretaceous successions are studied in boreholesections Romanovskaya 140 (Berriasian–Valanginian)and Gorshkovskaya 1017 (Hauterivian–basal Barre-mian). The first of these sections is composed of dark-colored shales in its lower part and of alternating silt-stones and sandstones in the upper one (Fig. 4). TheHauterivian–Barremian deposits of the second section

are represented by dark gray shales and sandstones(Fig. 2).

The lit-par-lit palynological analysis is performedfor the majority of sections (Fig. 2). Core samples havebeen selected for analysis with interval of 0.5 to 2 mdepending on composition of the rocks: preference wasgiven to clayey and silty sediments usually containingmost representative assemblages of palynomorphs.Before palynological analysis, rock samples have beentreated in hydrochloric and nitric acids, and in sodiumpyrophosphate solution. The cadmium liquid (CdI +KI) with specific gravity 2.25 was used to separateheavy fraction of sediments. Not less than 200 grainswere counted in each slide to determine percentage ofindividual taxa relative to total amount of microphyto-fossils (spores, gymnosperm pollen, microphytoplank-ton). Boundaries of palynostratigraphic units are sub-stantiated using the following criteria: first and lastoccurrences of species and genera, the grown diversityof certain genera and families, and increasing percent-age of particular taxa (as additional indication). A spe-cial attention was paid to stratigraphic distribution oftaxa most important for determination of biostrati-graphic boundaries. First or last occurrence of such a

0 400 km

KARA SEA

110°100°90°80°70°60°50°

sectionNordvik

sectionAnabar

Khatanga

Anabar R.

Dudunka

Borehole Severo-Vologochanskaya 18

Borehole Gorshkovskaya 1017

Borehole Romanovskaya 140

Surgut

Nizhnevartovsk

Yenisei R.

Taz R.

Pur R

.

Nadym R.

Ob R

.

75°

70°

65°

60°

Fig. 1.

Geographic localities of the studied sections.


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DINOCYST BIOSTRATIGRAPHY OF THE LOWER CRETACEOUS IN NORTH SIBERIA 579

taxon at the boundary of biostratigraphic unit corre-sponds respectively to its oldest or latest datum levelnot only in North Siberia, but also in other regions.To detect taxa of this kind, distribution of nearly300 dinocyst species have been analyzed in Lower Cre-taceous sections of Siberia (data on the studied sec-tions), northern Europe and America (published data).Species of greatest interest for the Lower Cretaceousstratigraphy of Siberia are listed in Fig. 5 and figured inPlates I and II. Consequently, boundaries of distin-guished dinocysts zones are in most cases the importantstratigraphic markers of a great correlation potential.

INVESTIGATION HISTORY OF LOWER CRETACEOUS DINOCYSTS IN SIBERIA

Systematic investigations of Lower Cretaceousmicrophytofossils from Siberia commenced in the ter-minal 1980s. Il’ina (1988) was first to study microphy-toplankton from the Jurassic–Cretaceous boundarydeposits in the Nordvik Peninsula, and Fedorova et al.(1993) examined the Berriasian dinocysts of theBoyarka River section. Dinocyst assemblages fromparticular ammonite zones have been described how-ever without distinguishing independent stratigraphicsubdivisions substantiated by dinocysts. Timoshinaet al. (1999) described for the first time the freshwatermicrophytoplankton from the Hauterivian, Barremianand Aptian deposits of the Khatanga depression, whileLebedeva and Nikitenko (1998, 1999) establishedalmost continuous succession of dinocysts zones in theYatriya River section (Subpolar Urals) beginning fromthe upper Volgian up to the lower Hauterivian inclusive.In the last works, the distinguished biostratigraphicunits have been correlated with the Boreal dinocystzonations of Europe and Canada, and basic trends ofmicrophytoplankton distribution depending on sedi-mentary facies have been elucidated. A few works arededicated to the same approach used for stratigraphicsubdivision of the Lower Cretaceous deposits recov-ered by drilling in unexposed areas of West Siberia(Mchedlishvili, 1971;

Multidisciplinary Study…

, 1978;Lebedeva and Pestchevitskaya, 1998; Kirichkova et al.,1999; Basel et al., 2002).

Limited data on dinocysts from the study regionhave been obtained by N. Aarhus (see in Shul’ginaet al., 1994) who studied these fossils in the Jurassic–Cretaceous boundary beds and the lower Berriasian ofthe Nordvik Peninsula. The upper Berriasian has notbeen investigated, whereas the Valanginian and Hau-terivian intervals have been sampled here at random.My own data characterize palynology of these intervalsmore exactly (Pestchevitskaya, 2002; Nikitenko et al.,2004). In addition, successions of microphytoplanktonassemblages have been established in the Lower Creta-ceous sections of the Anabar Bay eastern coast(Pestchevitskaya, 1999, 2000), Ust-Yenisei region(Nikitenko et al., 2004; Pestchevitskaya, 2005b), Pur–Taz interfluve (Lebedeva and Pestchevitskaya, 1998;

Zakharov et al., 1999), and around the latitudinal seg-ment of the Ob River (Pestchevitskaya, 2005a).

Comprehensive study of the dinocysts’ morphologywas used to clarify characterization of certain taxa, toanalyze their facies and paleogeographic distribution,and to describe new species (Pestchevitskaya, 2001,2003, 2006a, 2006b). Stages of dinocysts’ developmentin the Cretaceous seas of Siberia were identified, lateralradiation of microphytoplankton assemblages anddiversity dynamics of some taxonomic and morpholog-ical groups depending on evolution of environments inthe Siberian paleobasin were detected (Lebedeva andPestchevitskaya, 1997; Pestchevitskaya, 2002, 2003).The succession of the Berriasian–Barremian dinocystzones has been considered earlier (Pestchevitskaya,2005a, 2006). Description of these zones is presentedbelow for the first time.

DINOCYST ZONES OF THE LOWER CRETACEOUS IN NORTH SIBERIA

Pareodinioideae–Batioladinium varigranosum–Cassiculasphaeridia reticulata Zone (dinocyst

assemblage 1 (DZ1) (Figs. 2, 5)

Characteristic taxa.

Dinocysts of simple morphology(

Batiacasphaera norvikii

Burger,

Escharisphaeridiapsilata

Kumar,

Sentusidinium

spp.), typical of the bedsoccur in association with

Sirmiodinium grossii

Alberti,

Jansonia

spp.,

Microdinium opacum

Brideaux,

Sirmio-diniopsis orbis

Drugg,

Tubotuberella apatela

(Cooksonet Eisenack) Ioannides,

T. rhombiformis

Vozzhenni-kova,

Chlamydophorella nyei

Cookson et Eisenack,

Ambonosphaera

spp.,

Occisucysta wierzbowskii

Poulsen, and

Wrevittia helicoidea

(Eisenack et Cook-son) Helenes et Lucas-Clark. Abundance of the firstthree taxa can be significant. An important feature ispersistent diversity of the subfamily Pareodinioideae(

Paragonyaulacysta ?borealis

(Brideaux et Fisher)Stover et Evitt,

Pareodinia ceratophora

Deflandre,

P. minuta

Wiggins,

P. arctica

Wiggins,

Pluriarvaliumosmingtonense

Sarjeant,

Evansia evittii

(Pocock) Jan-sonius and others). Genera

Dingodinium, Fromea, Wal-lodinium, Cribroperidinium, Tubotuberella

, and

Apteo-dinium

are diverse as well. Stratigraphically importantspecies are

Cyclonephelium cuculliforme

(Davies)Aarhus,

Stanfordella exanguia

(Duxbury) Helenes etLucas-Clark,

Cassiculasphaeridia reticulata

Davey,

Achomosphaera neptunii

(Eisenack) Davey et Will-iams,

Dingodinium ?spinosum

(Duxbury) Davey,

Bati-oladinium varigranosum

(Duxbury) Davey,

Athigmato-cysta

aff.

glabra

Duxbury, and

Spiniferites ramosus

(Ehrenberg) Monteil. Also characteristic of the zone isoccurrence of

Horologinella anabarensis

Pestche-vitskaya,

Dingodinium minutum

Dodekova,

D. tubero-sum

(Gitmez) Fisher et Riley,

D. subtile

Pestche-vitskaya,

Cassiculasphaeridia magna

Davey,

Apteod-inium granulatum

Eisenack,

A. grande

Cookson etHughes,

A. maculatum

Eisenack et Cookson,

Circulod-

580


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PESTCHEVITSKAYA

BoreholeGorshkovskaya 1017

Anabar Bay easterncoast, exp. 1A Borehole

Romanovskaya 140

Nordvik Peninsula,exp. 35, 36

ZoneDZ8

Zone

Higher,correlation

Boreal standard

is not performedbecause of

fauna absencein section

of BoreholeGorshkovskaya

1017

Borehole Severo-Vologochanskaya 18

Homolsomitesbojarkensis

Nordvik Peninsula,exp. 33

Dichotomitesbidihotomus

Polypty-chitesbeani

Euryptychitesastieriptychus

Euryptychitesquadrifidus

Neotolliaklimovskiensis

Tollia tolli

Bojarkiameseznikowi

?

?

ZoneDZ5

with the

Zon

eD

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MN

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one

DZ

VL

G3

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rias

ian

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rem

ian

Stag

e

uppe

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wer

Subs

tage

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eal

zona

l s

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ard

(Zak

haro

v et

al.,

1997

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str.

unit

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epth

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ness

, m

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str.

unit

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35

32-3

4

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2.8

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31

30

29

28

27

26

25

4.2

2.5

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4

4.9

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2343

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628

2656

–264

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12.0

13.0

2750

–273

827

63–2

750

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1

19 2.5

18

17

16

15

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13

2.5

1.5

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DZ5


Vol. 15

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inium

spp.,

Cleistosphaeridium

spp.,

Cribroperidiniumtensiftense

Below,

Tanyosphaeridium magneticum

Davies, and

Leberidocysta spinose

Pestchevitskaya.

Lower boundary

is defined in the Nordvik Penin-sula only (Nikitenko et al. 2004) at the first occurrencelevel of

Batioladinium varigranosum, Cassiculas-phaeridia reticulata

, and

Tanyosphaeridium magneti-cum.

Remarks.

Basic taxa of the assemblage, representa-tives of the subfamily Pareodinioideae inclusive, arewidespread not only in the Berriasian of North Eurasia,but in the Upper Jurassic as well (Brideaux and Fisher,1976; Fisher and Riley, 1980; Rawson and Riley, 1982;Davey, 1982; Davies, 1983; Van Helden, 1986; Lebe-deva and Nikitenko, 1998; Riding et al., 1999). On theother hand, the assemblage includes stratigraphicallyimportant species, first occurrence of which is recordedin the Berriasian of Canada and northern Europe. Firstoccurrence of

Batioladinium varigranosum

in mid-Berriasian strata is known in northwestern Europe(Davey, 1982) and Newfoundland (Van Helden, 1986).Oldest

Cassiculasphaeridia reticulata

forms are foundat the base of the

Bojarkia payeri

Zone in the SubpolarUrals (Lebedeva and Nikitenko, 1998). In northernEurope, species

Tanyosphaeridium magneticum

hasbeen observed until present only in the Valanginian,Hauterivian and Barremian dinocyst assemblages(Davies, 1983; Nøhr-Hansen, 1993; Prössl, 1990). Animportant component of the assemblage is

D. ?spino-sum

, the characteristic Berriasian taxon regarded bysome researchers as zonal index species (Fisher andRiley, 1980; Rawson and Riley, 1982). Species

Tubotu-berella rhombiformis, Paragonyaulacysta ?borealis

and


are reported onlyfrom the Subpolar Urals (Lebedeva and Nikitenko,1998), Khatanga depression (Il’ina 1988; Shulgina etal., 1994; Riding et al., 1999) and Arctic Canada(Brideaux and Fisher, 1976; Davies, 1983) and can beconsidered as characteristic taxa of subpolar regions inSiberia and Canada. In the studied sections, the persis-tent occurrence of

Tubotuberella rhombiformis

is lim-ited by the top of zone DZ1. The first occurrence levelof


is an important strati-graphic indication, as in Arctic Canada this taxon is oneof index species of the respective Berriasian zone(Davies, 1983).

Paragonyaulacysta ?borealis

wide-spread in the Upper Jurassic and Berriasian deposits isaccepted to be the index species of the

Paragonyaula-cysta

?borealis–Dingodinium ?spinosum

dinocyst zone(within the extent of

Craspedites okensis

–basal

Neotol-

lia klimovskiensis

ammonite zones), which is recogniz-able in subpolar regions of Canada and Siberia (Bride-aux and Fisher, 1976; Pocock, 1980; Davies, 1983;Il’ina, 1988; Riding et al., 1999; Lebedeva andNikitenko, 1998, 1999; Nikitenko et al., 2004). Oldestspecimens of Achomosphaera neptunii have beenfound at the Berriasian Stage base in Boreal regions ofCanada (Williams et al., 1974; Jenkins et al. 1974;Bujak and Williams, 1978) and not far away from Mos-cow (Iosifova, 1996). In many sections of Greenlandand western Europe, this species has been found in theupper Berriasian and Valanginian (Duxbury, 1977;Davey, 1979; Piasecki, 1979; Fisher and Riley, 1980;Duxbury et al., 1999). In the studied sections, persistentoccurrence of Dingodinium subtile has been observedonly in the upper Berriasian, whereas its specimens areextremely rare at higher levels.

In the Pur–Taz interfluve (Borehole Romanovskaya140), where the zone DZ1 have not been detected, I dis-tinguished zone DZ RMN1 of the wider upper Berria-sian–lower Valanginian stratigraphic range.

Type section: the Nordvik Peninsula; Exposure 33,beds 31–59 of argillite-like silty splintery clays bluishto dark gray, with subordinate interlayers of brownishgray flaggy clay of lesser thickness and with thin lentic-ular intercalations and concretions of limestone (Basovet al., 1970; Zakharov et al., 1983).

Distribution: Khatanga depression (middle part ofthe Paksa Formation); Ust-Yenisei region (uppermostNizhnyaya Kheta and basal Sukhaya Dudinka forma-tions).

Stratigraphic position: Upper Berriasian–basalValanginian interval corresponding to extent of theSurites analogus and basal Neotollia klimovskiensisammonite zones; established based on direct correla-tion with zones of the Boreal standard in section of theNordvik Peninsula (Basov et al., 1970; Zakharov et al.,1983).

Paragonyaulacysta sp.–Batiacasphaera sp. Zonewith DZ RMN1 (Fig. 2)

Characteristic taxa. Dinocysts are of extremelylow taxonomic diversity, represented by Paragonyaul-acysta sp., Batiacasphaera sp., and by poorly preservedproximate and chorate forms.

Lower boundary is tentatively defined at the sec-tion base.

Fig. 2. Correlation chart of the studied sections based on the established dinocyst zones in the north of Western and central Siberia.The lit-par-lit division of sections is done using the following works: Nordvik Peninsula—Basov et al., 1970; Zakharov et al., 1983;Bogomolov, 1989; Anabar Bay eastern coast—Bogomolov et al., 1983; Bogomolov, 1989; Borehole Severo-Vologochanskaya 18—Nikitenko et al., 2004; Borehole Romanovskaya 140—Zakharov et al., 1999; Borehole Gorshkovskaya 1017—unpublished data ofV.A. Kazanenkov and O.O. Savchenkova. Lithology: (1) sands, sandstones; (2) sandy aleurolites; (3) sandy aleurites; (4) aleurites;(5) silty clays; (6) clayey aleurolites; (7) argillites; (8) clays; (9) pebbles; (10) calcareous interlayers and concretions; (11) ammo-nites; (12) bivalves; (13) fucoids; (14) sampling levels for palynological analysis.

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STRATIGRAPHY AND GEOLOGICAL CORRELATION Vol. 15 No. 6 2007

PESTCHEVITSKAYA

Nizh-yayaKheta

Foundmacrofauna,foraminiferalassemblages

Cribrostomoidesinfracretaceous,

ë. sinuosus

Valanginellatatarica

Neotollia klimovskiensis

Gaudryina gerkei, Tro-

Abridged lithologic characterization

Interlayering dark gray aleurites and gray sandy aleurites;bioturbation marks; layer of dark gray sideriteconcretions at the base

Aleurites, gray, vaguely laminated, sometimes sandy withclay ooids (in lower part) and rare interlayers of dark gray clayey aleurites; bioturbation marks

Fine interlayering of light gray sandy aleurites, aleurites and dark gray clayey aleurites; occasional interlayers of darkgray vaguely-laminated clay and light gray, sometimes greenish sand;bioturbation marks

Interlayering of gray sandy aleurites, dark gray clays and greenish sands; bioturbation marks;a bed of gray sideritic aleurite at the base

Aleurites, greenish gray, often sandy, with laminae of graysandy aleurite and dark gray silty clay;bioturbation marks; bed of gray sideritic sandstoneat the base

Aleurites, gray to greenish gray, sandy, with horizontal,cross and lenticular lamination; interlayers of gray to lightgray and greenish sands in the upper part;bioturbation marks; bed of gray sideritic aleuroliteat the base

Interlayering of dark gray silty horizontally-laminatedclays and greenish gray sandy aleurites;bioturbation marks

Interlayering light gray sands and gray sandy aleurites of the lower half grade upward into dark gray to greenishsandy aleurites with laminae of dark grayclayey aleurite; bioturbation marks;dark gray bed of sideritic sandstone at the base

Aleurites, gray to dark gray, sandy, with horizontalor lenticular lamination, locally with lenticlesand laminae of light gray sand; bioturbation marks

Aleurites, dark gray, with lenticular bedding, enclosing interlayersof gray sandy aleurite and rare pebbles

?

chammina rosaceaforrnisBer

ri-

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ss, m

Zon

e D

Z1

Zon

e D

Z2

Zon

e D

Z V

LG

3D

inoc

yst

zone

Lith

olog

y

854.

8–84

2.3

12.5

12.0

18.1

12.1

13.2

20.3

9.0

22.0

20.4

6.7

988.

6–98

1.9

Fig. 3. The Lower Cretaceous section recovered by Borehole Severo-Vologochanskaya 18 (additional data from Nikitenko et al.,2004; symbols as in Fig. 2).



Remarks. Because of a very low diversity ofdinocysts, it is impossible to define precisely strati-graphic position of the zone. Occurrence of Paragon-yaulacysta sp. facilitates determination of their upperboundary only. As is established, representatives of thisgenus do not occur above the Neotollia klimovskiensisZone in sections of the Nordvik Peninsula and the Ana-bar Bay eastern coast. The upper boundary is tenta-tively defined in the upper Berriasian.

Type section: Borehole Romanovskaya 140, depthinterval 3027–3020.5 m; sediments are represented byblack foliated argillites 6.5 m thick.

Distribution: Pur–Taz interfluve (lower part of theSortym Formation).

Stratigraphic position: upper Berriasian–basalValanginian.

Escharisphaeridia spp.–Oligosphaeridium spp.–Circulodinium spp. Zone (DZ2, Figs. 2, 5)

Characteristic taxa. Diversity of dinocysts is com-paratively low. Main components of the assemblage areforms of simple morphology (Escharisphaeridia spp.,Batiacasphaera spp., Sentusidinium spp.) and poorlypreserved proximate dinocysts. Persistently occurringspecies are Dingodinium spp., D. minutum, Oli-gosphaeridium spp., Cleistosphaeridium spp., some-times Chlamydophorella spp., Cassiculasphaeridiareticulata and Jansonia spp. Species Sirmiodiniumgrossii, Circulodinium spp., Tubotuberella apatela, Tri-chodinium spp., Horologinella anabarensis, Cribrope-ridinium exilicristatum (Davey) Stover et Evitt, C. aff.sarjeantii (Vozzhennikova) Helenes, some other Cribro-peridinium forms, Apteodinium maculatum, A. granula-tum, A. ?vescum Matsuoka, and A. cf. grande occur fre-quently. An important feature is the declined diversity

Found macrofauna,foraminiferal assemblages

2753.5Astarte veneriformis Zakh.,Discina sp. indet.

2765.5Striatomodiolus sibiricus (Bod.)

Neotollia klimovskiensis (Krymh.),Euryptychites quadrifidus (Kemp.)

2772

3023Buchia sp. indet.

Abridgedlithologic

characterization

Sandstone, fine-grained,

Aleurites, light gray, clayey, sandy

Clayey aleuritewith sandy laminae

Interlayeringof silty sandstonesand argillites

Aleurolites, highlyclayey, splintery

Sandstone,fine-grained, massive

Argillite, gray,foliated

Argillite, black,foliated

Astarte veneriformis Zakh.Pinna sp. indet.

clayey-silty, bioturbated;

in upper part

?

Ber

rias

ian–

low

er V

alan

gini

anL

ower

Val

angi

nian

Stag

e, s

ubst

age

Sort

ymFo

rmat

ion

3027

–302

0.5

3020

.5–

3016

2784

–277

427

74–2

768

2768

–27

6527

65–2

758

2758

–275

127

51–

2747

Inte

rval

, m

Thi

ckne

ss, m

Lith

olog

y

Evo

lutin

ella

gra

ndis

ass

embl

age

of fo

ram

inif

ers

Zon

eZ

one

DZ

3D

inoc

yst

zone

DZ

RM

N1

4.0

7.0

7.0

3.0

6.0

10.0

4.5

6.5

Fig. 4. The Lower Cretaceous section recovered by Romanovskaya 140 (additional data from Zakharov et al., 1999; symbols as inFig. 2).

584


PESTCHEVITSKAYA

of Pareodinioideae represented by Pluriarvalium spp.,P. osmingtonense, Pareodinia spp., P. arctica, andP. ceratophora, which occur irregularly. New formsoccurring are Nelchinopsis kostromiensis (Vozzhennik-ova) Wiggins, Sentusidinium granulatum (Courtinat)Stover et Williams, Circulodinium brevispinosum(Pocock) Jansonius, Aprobolocysta sp., and Trichodin-ium ciliatum (Gocht) Eisenack et Klement.

Lower boundary defined in sections of the Nord-vik Peninsula and Borehole Severo-Vologochanskaya18 marks the last occurrence of Pagaronyaulacystaspp. and P. ?borealis, the diversity decrease of Pareod-inioideae, and persistent presence of Oligosphaeridiumspp. In the Nordvik Peninsula, Tubotuberella spp. andDingodinium subtile occur at random above this leveland T. rhombiformis disappears from the assemblage.Species Wallodinium krutzschii and Wrevittia heli-coidea do not occur above this level in BoreholeSevero-Vologochanskaya 18; Dingodinium ?spinosum

and Pareodinia minuta become extinct somewhatlower.

Remarks. The last occurrence of Paragonyaula-cysta ?borealis in the Valanginian basal interval isestablished in Arctic Canada, Greenland, Norway andSiberia, i.e., in the circum-Arctic regions, and therespective level is therefore a reliable stratigraphicmarker (Aarhus et al., 1986; Aarhus et al., 1990; Shul-gina et al., 1994; Lebedeva and Nikitenko, 1998;Nikitenko et al., 2004). The last occurrence level ofD. ?spinosum, which is practically coincides with theBerriasian top in northern regions of western Europe(Duxbury 1977; Davey, 1979; Fisher and Riley, 1980;A Stratigraphic…, 1992; Duxbury et al., 1999), is theother important marker.

It is likely that the beds are thicker in Exposure 35(Nordvik Peninsula) and span lower part of the Euryp-tychites quadrifidus Zone (Fig. 2), but having no sam-ples from this part of the section for palynological anal-

Basic palynologicalcriteria ofboundaries

Northern regionsof Eurasia and America,

where the same boundarycriteria are established

Characteristic speciesStratigraphically important dinocyst species

from North Siberia and other„northern regions of Eurasia and America

Batioladinium ?exiguum, Wallodiniumkrutzschii

Muderongia staurota, M. crucis, M. tetracan-tha, M australis, Batioladinium jaegeri, B.longicornutum, B. ?exiguum, Gardodiniumtrabeculosum, Cribroperidinium confossum,ë. ?edwardsii, ë. ?muderongense, Cassicu-lasphaeridia reticulata, Dingodinium cerviculum, Circulodinium distinction, Pseudoce-ratium pelliferum, Hystrichodinium voigtii,H. pulchrum, Oligosphaeridium complex,Nelchinopsis kostromiensis

Muderongia simplex, Cassiculasphaeridiareticulata, Wrevittia helicoidea, Nelchi-nopsis kostromiensis, Stanfordella ?creta-cea, Batioladinium varigranosum, Din-godinium cerviculum, Circulodinium dis-tinctum Chlamydophorella nyei, Wallodi-nium luna, Apteodinium granulatum, Tri-chodinium ciliatum, Apteodinium spon-

gosphaeridium diluculum,Heslertonia heslertonensis

Cassiculasphaeridia magna,Wallodiniumkrutzchii, Dingodinium ?albertii, D. minu-tum, D. tuberosum, Pareodinia cerato-phora, Fromea amphora, Tubotuberellaapatela, Sirmiodinium grossii, Sirmiodi-niopsis orbis

Nelchinopsis kostromiensis Northwestern Europe

Aprobolocysta eilema Northwestern Europe

First occurrence of Vesperopsis fragilis

Last occurrence of Tenua americana

First occurrence of Aprobolocystaeilema

First occurrence of Aptea anaphrissaSubpolar Urals

First occurrence of Hystrichodiniumsolare Subpolar Urals

First abundance peak ofDingodinium cerviculumAldorfia sibirica

Only in the north

Dingodinium cerviculum

Oligosphaeridiumcomplex Eurasia and America

South England

Northern Germany

Northwestern Europe

Barents Sea shelf,

of Central Siberia

Arctic Canada, Siberia

Everywhere in the north of

Last occurrence of Paragonyaula-cysta ?borealis

Arctic Canada, Greenland,Norway, Siberia

Last occurrence of Digodinium?spinosum

Northwestern Europe

First occurrence of Batioladiniumvarigranosum

Canada, northwesternEurope

First occurrence of Cassiculaspha-eridia reticulata Subpolar UralsB

erri

asia

nV

alan

gini

anH

aute

rivi

anB

arre

mia

nSt

age

low

erup

per

Subs

tage

Din

ocys

t

Low

erbo

unda

ries

of b

eds

Firs

t occ

u-L

ates

t fin

ds

mid

dle

low

erup

per

uppe

rlo

wer

low

erup

per

zone

rren

ce o

f

DZ8

DZ8

DZ7

DZ6

DZ5

DZ4

DZ3

DZ2

DZ1

?

DZ7

DZ6

DZ5

DZ4

DZ3

DZ2

DZ1

Cas

sicu

lasp

haer

idia

mag

na

Apt

eodi

nium

spo

ngio

sum

Am

bono

splia

era

?sta

ffiie

nsis

Cir

culo

dini

um c

ompt

a

Am

bono

sphe

ra d

elic

ata

Tubo

tube

rella

rho

mbi

form

is

Din

godi

nium

tube

rosu

m

End

oscr

iniu

m p

haro

Din

godi

nium

min

utum

Oci

ssuc

ysta

wie

rzbo

wsk

ii

Par

agon

yaul

acys

ta ?

bore

alis

giosum, OliO. ?asterigium,

Fig. 5. Palynological substantiation of dinocyst zones, their stratigraphic position and generalized stratigraphic extents of strati-graphically important dinocysts (stratigraphic analysis and palynological comparison of Siberian, European and Canadian biostrati-graphic units are performed using original and published data from works cited in the text and Table 4).



ysis I failed to define precisely the upper boundaryposition here.

Type section: the Nordvik Peninsula; Exposure 33,beds 60–64 of dark gray, argillite-like, silty splinteryclays and clayey aleurites with interlayers of limestoneconcretions; thickness 7.7 m; Exposure 35, beds 18–22of dark gray silty clay with lens-like limestone concre-tions; thickness 12.5 m (Basov et al., 1970; Zakharovet al., 1983; Bogomolov, 1989).

Distribution: Khatanga depression (middle part ofthe Paksa Formation); Ust-Yenisei region (lower part ofthe Sukhaya Dudinka Formation without very basalinterval).

Stratigraphic position: the basal Valanginian,ammonite zones Neotollia klimovskiensis without itslowermost part and Euryptychites quadrifidus in itslower part; established based on direct correlation withthe Boreal standard zones in sections of the NordvikPeninsula (Basov et al., 1970; Zakharov et al., 1983;Bogomolov, 1989) and of the Anabar Bay eastern coast(Zakharov et al., 1983; Bogomolov, 1989).

Oligosphaeridium complex–Dingodinium cerviculum Zone (DZ3, Figs. 2,5)

Characteristic taxa. The grown diversity ofdinocysts, persistently occurring among which are Cas-siculasphaeridia magna, Sirmiodinium grossii,Chlamydophorella nyei, Oligosphaeridium ?asteri-gium (Gocht) Davey et Williams, Fromea amphora,F. fragilis, Pareodinia ceratophora, Wallodinium luna,Dingodinium minutum, Muderongia simplex Albertiemend. Riding et al., and representatives of genera Din-godinium, Oligosphaeridium, Cleistosphaeridium,Escharisphaeridia, Sentusidinium, and Circulodinium.A high diversity of the genus Oligosphaeridium is espe-cially remarkable. In West Siberia, diversification of thegenus Muderongia is established. Of prime importanceis appearance of new species Dingodinium cerviculumCookson et Eisenack emend. Khowaja-Ateequzzmanet al., Muderongia cruces Neale et Sarjeant, M. austra-lis Helby, Gardodinium trabeculosum (Gocht) Alberti,Oligosphaeridium complex (White) Davey et Williams,O. albertense (White) Davey et Williams, O. diluculum

Stratigraphically important dinocyst speciesfrom North Siberia and othernorthern regions of Eurasia and America

Tany

osph

aerd

ium

mag

netic

um

Bat

iola

dini

um ja

eger

i

Cri

brop

erid

iniu

m ?

mud

eron

gens

e

Dow

nies

phae

ridi

um a

cicu

lare

Apr

obol

ocys

ta g

alea

ta

Mud

eron

gia

crur

is

Mud

eron

gia

aust

ralis

Cri

brop

erid

iniu

m o

rtho

cera

s

Din

godi

nium

cer

vicu

lum

(A

rctic

regi

ons)

Olig

osph

aeri

dium

com

plex

Gar

dodi

nium

trab

ecul

osum

(A

rctic

regi

ons)

Mud

eron

gia

tetr

acan

tha

Bat

iola

dini

um lo

ngic

ornu

tum

Dis

cors

ia n

anna

Cau

ca p

arva

Hys

tric

hodi

nium

sol

are

Gar

dodi

niun

i ord

inal

e

Dap

silid

iniu

m m

ultis

pino

sum

Mud

eron

gia

asym

met

rica

Mud

eron

gia

stau

rota

Cyc

lone

phel

ium

bre

visp

inat

um

Kio

kans

ium

pol

ypes

Apt

ea a

naph

riss

aA

prob

oloc

ysta

nei

sta

Odo

ntoc

hitin

a op

ercu

lata

Cyc

lone

phel

ium

into

nsum

Ves

pero

psis

frag

ilig

Apr

obol

ocys

ta e

ilem

a

Bat

iola

dini

um ?

exig

uum

Bat

iola

dini

um v

arig

rano

sum

Nel

chin

opsi

s ko

stro

mie

nsis

Cas

sicu

lasp

haer

idia

ret

icul

ata

Mud

eron

gia

“tom

aszo

vens

is”

Olig

osph

aeri

dium

alb

erte

nse

Cri

brop

erid

iniu

m ?

mud

eron

gens

e

Din

godi

nium

sub

tilis

Din

godi

nium

?sp

inos

um

Hes

lert

onia

hes

lert

onen

sis

End

oscr

iniu

m c

ampa

nula

Cir

culo

dini

um d

istin

ctum

Apt

eodi

nium

mac

ulat

um

Din

godi

nium

cer

vicu

lum

(B

orea

l reg

ions

)

Ach

omos

pher

a ne

ptun

ii

Spin

iferi

tes

ram

osus

Mud

eron

gia

brev

ispi

nosa

Gar

dodi

nium

trab

ecul

osum

(B

orea

l reg

ions

)

Ath

igm

atoc

ysta

gla

bra

Cyc

lone

phel

ium

cuc

ullif

orm

e

Fig. 5. (Contd.)

586


PESTCHEVITSKAYA

Plate I

1 2 3 4

5

6 78 9

1011

1213 14

15 16 1718

19

20

21

22

2324

25 26 27 28 29



Davey, Circulodinium distinctum (Deflandre et Cook-son) Jansonius, Aprobolocysta galeata Backhouse,Canningiopsis colliveri (Cookson et Eisenack) Back-house, Cribroperidinium ?muderongense (Cookson etEisenack) Davey, C. orthoceras (Eisenack) Davey,Wrevittia cassidata (Eisenack et Cookson) Helenes etLucas-Clark, and Trichodinium speetonense Davey.

Lower boundary is defined at the first occurrencelevel of Oligosphaeridium complex and Dingodiniumcerviculum in section of the Anabar Bay eastern coastonly.

Remarks. Taxa always present in the assemblageare also widespread in underlying deposits, the UpperJurassic strata inclusive (see description and remarks toDA1 and DA2). However, newly appeared taxa of DA3are stratigraphically important being known from theLower Cretaceous dinocyst assemblage far beyond

Siberia in northern Europe and Canada. In westernEurope, the first occurrence of Dingodinium cervicu-lum is established at the level of the upper Volgian Sub-stage (Davey, 1979), whereas in northern regions ofCanada and Siberia this species occurs beginning fromthe basal Valanginian (McIntyre and Brideaux, 1980;Davies, 1983; Lebedeva and Nikitenko, 1998). Innorthern sections of Eurasia and America, the firstoccurrence level of Oligosphaeridium complex is prac-tically isochronous, corresponding approximately tothe base of the Buchia keyserlingi Zone, thus being agood stratigraphic marker (Duxbury, 1977, 2001;Bujak and Williams, 1978; Piasecki, 1979; Davey,1979; McIntyre and Brideaux, 1980; Davies, 1983;Aarhus et al., 1986; A Stratigraphic…, 1992). Firstoccurrences of Muderongia crucis and Cribroperidin-ium ?muderongense are established in the lower Val-

Plate I. Dinocysts of the Lower Cretaceous from northern areas of Siberia. Collection no. 842, is stored at the Central Siberian Geo-logical Museum, Trofimuk Institute of Petroleum geology and Geophysics, Siberian Division, Russian Academy of Sciences,Novosibirsk.(1) Barbatacysta brevispinosa (Courtinat) Courtinat. Nordvik Peninsula, Exposure 33, Bed 31, Sample 31.1, Specimenno. 107.1/11, Paksa Formation, Berriasian, Surites analogus Zone, × 420; (2) Apteodinium granulatum Eisenack. Nordvik Penin-sula, Exposure 33, Bed 31, Sample 31.1, Specimen no. 107.2/36, Paksa Formation, Berriasian, Surites analogus Zone, × 450; (3)Pluriarvalium osmingtonense Sarjeant. Nordvik Peninsula, Exposure 33, Bed 32, Sample 32.1, Specimen no. 110.1/30, Paksa For-mation, Berriasian, Surites analogus Zone, ×450; (4) Aldorfia sibirica Pestchevitskaya. eastern coast of the Anabar Bay, Exposure1A, Bed 20, Sample 31, Specimen no. 31.1/13, Paksa Formation, lower Valanginian, Siberites ramulicosta Zone, beani Subzone,×450; (5) Batioladinium jaegeri (Alberti) Brideaux. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample38, Specimen no. 1403.5/6, Cherkashino Formation, upper Hauterivian, ×420; (6) Athigmatocysta aff. glabra Duxbury. West Sibe-ria, Borehole Severo-Vologochanskaya 18, depth 988.6 m, Sample 47, Specimen no. 1763.1/20, Nizhnyaya Kheta Formation, Ber-riasian, ×470; (7) Cribroperidinium tensiftense Below. West Siberia, Borehole Severo-Vologochanskaya 18, depth 950.2 m, Sample80, Specimen no. 1733.1/8, Sukhaya Dudinka Formation, lower Valanginian, ×400; (8) Apteodinium grande Cookson et Hughes.Nordvik Peninsula, Exposure 33, Bed 31, Sample 31.1, Specimen no. 107.2/28, Paksa Formation, Berriasian, Surites analogusZone, ×350; (9) Endoscrinium vellum Pestchevitskaya. Nordvik Peninsula, Exposure 33, Bed 51, Sample 51.1, Specimenno. 135.1/10.a, Paksa Formation, Valanginian, Neotollia klimovskiensis Zone, ×500; (10) Muderongia brevispinosa Iosifova. Nor-dvik Peninsula, Exposure 36, Bed 11, Sample 11.2, Specimen no. 1090.3/8, Paksa Formation, Hauterivian, Homolsomites bojarken-sis Zone, ×250; (11) Aprobolocysta neista Duxbury. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38,Specimen no. 1403.2/45, Cherkashino Formation, upper Hauterivian, × 320; (12) Muderongia endovata Riding et al. West Siberia,Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38, Specimen no. 1403.1/16, Cherkashino Formation, upper Hau-terivian, ×270; (13) Endoscrinium sp. Nordvik Peninsula, Exposure 35, Bed 35, Sample 35.1, Specimen no. 1075.1/5, Paksa For-mation, lower Valanginian, Euryptychites astieriptychus Zone, ×480; (14) Muderongia australis Helby. eastern coast of the AnabarBay, Exposure 1A, Bed 20, Sample 30, Specimen no. 30.1/9, Paksa Formation, lower Valanginian, Siberites ramulicosta Zone,Beani Subzone, ×480; (15) Batiacasphaera sp. Nordvik Peninsula, Exposure 33, Bed 32, Sample 32.1, Specimen no. 110.1/19,Paksa Formation, Berriasian, Surites analogus Zone, ×400; (16) Taleisphaera sp. West Siberia, Borehole Gorshkovskaya 1017,interval 2628–2642 m, Sample 38, Specimen no. 1403.5/20, Cherkashino Formation, upper Hauterivian, ×490; (17) Evansia evittii(Pocock) Jansonius. Nordvik Peninsula, Exposure 33, Bed 32, Sample 32.1, preparation 110.1, Specimen 20, Paksa Formation, Ber-riasian, Surites analogus Zone, ×300; (18) Dingodinium minutum (Gitmez) Fisher et Riley. Nordvik Peninsula, Exposure 33, Bed37, Sample 37.1, Specimen no. 115.1/8, Paksa Formation, Berriasian, Bojarkia meseznikovi Zone, ×400; (19) Apteodinium ?vescumMatsuoka. Nordvik Peninsula, Exposure 33, Bed 46, Sample 46.1, Specimen no. 128.1/11, Paksa Formation, Berriasian, Tollia tolliZone, ×300; (20) Tubotuberella rhombiformis Vozzhennikova. Nordvik Peninsula, Exposure 33, Bed 41, Sample 41.1, Specimenno. 123.1/2, Paksa Formation, Berriasian, Tollia tolli Zone, ×420; (21) Pareodinia minuta Wiggins. West Siberia, Borehole Severo-Vologochanskaya 18, depth 984.3 m, Sample 50, Specimen no. 1760.1/9, Nizhnyaya Kheta Formation, Berriasian, ×450;(22) Chlamydophorella nyei Cookson et Eisenack. eastern coast of the Anabar Bay, Exposure 1A, Bed 12, Sample 18, Specimenno. 18.4/8, Paksa Formation, lower Valanginian, Euryptychites astieriptychus Zone, ×320; (23) Horologinella anabarensisPestchevitskaya. eastern coast of the Anabar Bay, Exposure 1A, Bed 12, Sample 18, Specimen no. 18.1/26, Paksa Formation, lowerValanginian, Euryptychites astieriptychus Zone of ammonites, ×550; (24) Gardodinium ordinale Davey. West Siberia, BoreholeGorshkovskaya 1017, interval 2615–2628 m, Sample 58, Specimen no. 1423.1/15, Cherkashino Formation, upper Hauterivian,×360; (25) Dingodinium subtile Pestchevitskaya. Nordvik Peninsula, Exposure 33, Bed 42, Sample 42.1, Specimen no. 124.1/10,Paksa Formation, Berriasian, Tollia tolli Zone, ×350; (26) Cleistosphaeridium sp. Nordvik Peninsula, Exposure 33, Bed 37, Sample37.1, Specimen no. 115.1/11, Paksa Formation, Berriasian, Bojarkia meseznikovi Zone, ×400; (27) Spiniferites ramosus (Ehren-berg) Monteil. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38, Specimen no. 1403.4/15, Cherkash-ino Formation, upper Hauterivian, ×290; (28) Paragonyaulacysta ?borealis (Brideaux et Fisher) Stover et Evitt. Nordvik Peninsula,Exposure 33, Bed 31, Sample 31.1, Specimen no. 107.1/26, Paksa Formation, Berriasian, Surites analogus Zone, ×470; (29) Oli-gosphaeridium complex (White) Davey et Williams. eastern coast of the Anabar Bay, Exposure 1A, Bed 21, Sample 34, Specimenno. 34.1/7, Paksa Formation, lower Valanginian, Siberites ramulicosta Zone, Beani Subzone, ×390.

588


PESTCHEVITSKAYA

Plate II

1 2 3 45

6 7

8

9 10

11

12

13

14

15

16

17

18

19

20

21 2223

24 25

26 27 28 29 30



anginian of northern Europe, Arctic Canada and Subpo-lar Urals (Davey, 1979; Davies, 1983; Aarhus et al.,1986; Lebedeva and Nikitenko 1998). Species Mud-erongia australis, Aprobolocysta galeata and Cannin-giopsis colliveri constantly occur in the Hauterivian(Iosifova, 1996; Prössl, 1990; Nøhr-Hansen, 1993;Aarhus et al., 1986, 1990). Consequently, dinocystsinherited from the Jurassic communities and taxa char-acteristic of the Lower Cretaceous are already of equalsignificance in the assemblage that is its important fea-ture.

Zones DZ3 are probably of a greater thickness insection of the Nordvik Peninsula, but having no oppor-

tunity to analyze samples from lower part of the Euryp-tychites quadrifidus Zone I was unable to define withprecision the position of lower boundary here (Fig. 2).This subdivision is undetectable in the Ust-Yeniseiregion, and there is established zone DZ VLG3 span-ning upper part of the lower Valanginian, upper Valang-inian, and presumably basal Hauterivian.

Type section: eastern coast of the Anabar bay,Exposure 1A, beds 6–15: beds 6–13 are composed ofdark gray silty clay with calcareous concretions; beds14, 15 of gray clayey to sandy-clayey aleurites with cal-careous concretions; total thickness 76.1 m (Bogo-molov et al., 1983; Bogomolov, 1989).

Plate II. Dinocysts of the Lower Cretaceous from northern areas of Siberia. Collection no. 842, is stored at the Central SiberianGeological Museum, Trofimuk Institute of Petroleum geology and Geophysics, Siberian Division, Russian Academy of Sciences,Novosibirsk.(1) Aptea anaphrissa (Sarjeant) Sarjeant et Stover. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 35,Specimen no. 1400.1/1, Cherkashino Formation, lower Hauterivian, ×300; (2) Achomosphaera neptuni (Eisenack) Davey et Will-iams. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 36, Specimen no. 1401.1/2, Cherkashino For-mation, lower Hauterivian, ×420; (3) Occisucysta wierzbowskii Poulsen. West Siberia, Borehole Severo-Vologochanskaya 18, depth984,3 m, Sample 50, Specimen no. 1760.1/12, Nizhnyaya Kheta Formation, Berriasian, ×370; (4) Cribroperidinium aff. janinaeGyrka. Nordvik Peninsula, Exposure 35, Bed 34, Sample 34.4, Specimen no. 1074.2/26, Paksa Formation, lower Valanginian,Euryptychites astieriptychus Zone, ×440; (5) Batioladinium longicornutum (Alberti) Brideaux. West Siberia, Borehole Gorshk-ovskaya 1017, interval 2628–2642 m, Sample 30, Specimen no. 1395.1/11, Cherkashino Formation, lower Hauterivian, ×320;(6) Hystrichodinium solare Pestchevitskaya. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38, Spec-imen no. 1403.1/40, Cherkashino Formation, upper Hauterivian, ×300; (7) Hystrichodinium voigtii (Alberti) Davey. West Siberia,Borehole Gorshkovskaya 1017, interval 2615–2628 m, Sample 58, Specimen no. 1423.2/5, Cherkashino Formation, upper Hau-terivian, ×360; (8) Leberidocysta spinosa Pestchevitskaya. Nordvik Peninsula, Exposure 35, Bed 39, Sample 39.3, Specimen no.1081.2/3, Paksa Formation, lower Valanginian, Siberites Zone, ×380; (9) Mendicodinium sp. West Siberia, Borehole Gorshkovskaya1017, interval 2615–2628 m, Sample 59, Specimen no. 1424.1/2, Cherkashino Formation, upper Hauterivian, ×340; (10) Cymosos-phaeridium “?phoenix” (Duxbury) Fauconnier. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 36,Specimen no. 1401.1/4, Cherkashino Formation, lower Hauterivian, ×570; (11) Muderongia mcwhaei Cookson et Eisenack. WestSiberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 34, Specimen no. 1399.1/7, Cherkashino Formation, lowerHauterivian, ×420; (12) Pseudoceratium pelliferum Gocht. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m,Sample 38, Specimen no. 1403.6/1, Cherkashino Formation, upper Hauterivian, ×300; (13) Nelchinopsis kostromiensis (Vozzhen-nikova) Wiggins. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38, Specimen no. 1403.5/3,Cherkashino Formation, upper Hauterivian, ×440; (14) Aprobolocysta cornuta Pestchevitskaya. West Siberia, Borehole Gorshk-ovskaya 1017, interval 2628–2642 m, Sample 38, Specimen no. 1403.6/15, Cherkashino Formation, upper Hauterivian, ×360;(15) Aprobolocysta galeata Backhouse. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 40, Specimenno. 1405.1/9, Cherkashino Formation, upper Hauterivian, ×330; (16) Oligosphaeridium aff. totum Brideaux: West Siberia, BoreholeGorshkovskaya 1017, interval 2628–2642 m, Sample 33, Specimen no. 1398.1/6, Cherkashino Formation, lower Hauterivian, ×450;(17) Aprobolocysta eilema Duxbury. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38, Specimen no.1403.1/14, Cherkashino Formation, upper Hauterivian, ×360; (18) Tanyosphaeridium isocalamum (Deflandre et Cookson) Daveyet Williams. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38, Specimen no. 1403.2/12, CherkashinoFormation, lower Hauterivian, ×430; (19) Cassiculasphaeridia reticulata Davey. West Siberia, Borehole Severo-Vologochanskaya18, depth 950,2 m, Sample 80, Specimen no. 1733.1/8, Sukhaya Dudinka Formation, lower Valanginian, ×490; (20) Batioladiniumreticulatum Stover et Helby: West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38, Specimenno. 1403.4/4, Cherkashino Formation, upper Hauterivian, ×390; (21) Cyclonephelium brevispinatum (Millioud) Below. West Sibe-ria, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 37, Specimen no. 1402.1/18, Cherkashino Formation, upperHauterivian, ×330; (22) Florentinia sp. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 38, Specimenno. 1403.3/16, Cherkashino Formation, upper Hauterivian, ×260; (23) Vesperopsis mayi Bint. West Siberia, Borehole Gorshk-ovskaya 1017, interval 2615–2628 m, Sample 58, Specimen no. 1423.2/6, Cherkashino Formation, upper Hauterivian, ×400;(24) Pseudoceratium aff. expolitum Brideaux. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 37,preparation 1402.1, Specimen 12, Cherkashino Formation, upper Hauterivian, ×450; (25) Spiniferites aff. hyperacanthus (Deflandreet Cookson) Cookson et Eisenack. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 32, Specimen no.1397.1/2, Cherkashino Formation, lower Hauterivian, ×300; (26) Dingodinium cerviculum Cookson et Eisenack emend. Khowaja–Ateequzzman et al. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 40, Specimen no. 1405.2/1,Cherkashino Formation, upper Hauterivian, ×350; (27) Batioladinium varigranosum (Duxbury) Davey. Nordvik Peninsula, Expo-sure 35, Bed 35, Sample 35.1, Specimen no. 1075.2/26, Paksa Formation, lower Valanginian, Euryptychites astieriptychus Zone,×300; (28) Chytroeisphaeridia sp. Nordvik Peninsula, Exposure 35, Bed 35, Sample 35.1, Specimen no. 1075.1/2, Paksa Formation,lower Valanginian, Euryptychites astieriptychus Zone, ×450; (29) Muderongia cruces Neale et Sarjeant. West Siberia, BoreholeGorshkovskaya 1017, interval 2615–2628 m, Sample 41, Specimen no. 1406.2/5, Cherkashino Formation, upper Hauterivian, ×300;(30) Muderongia tetracantha (Gocht) Alberti. West Siberia, Borehole Gorshkovskaya 1017, interval 2628–2642 m, Sample 32,Specimen no. 1397.1/8, Cherkashino Formation, lower Hauterivian, ×410.

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PESTCHEVITSKAYA

Distribution: Khatanga depression (middle part ofthe Paksa Formation); Pur–Taz interfluve (middle partof the Sortym Formation.

Stratigraphic position: lower Valanginian; ammo-nite zones Euryptychites quadrifidus (lower part),Euryptychites astieriptychus, and lower part of Siber-ites ramulicosta Subzone; established based on directcorrelation with the Boreal standard zones in sectionsof the Nordvik Peninsula (Basov et al., 1970; Zakharovet al., 1983; Bogomolov, 1989) and the Anabar Bayeastern coast (Zakharov et al., 1983; Bogomolov,1989).

Sentusidinium spp.–Apteodinium spp. Zone(DZ VLG3, Fig. 2)

Characteristic taxa. Most frequently occurring inthe assemblage are Sentusidinium spp.,Escharisphaeridia spp., Apteodinium spp., and Cassic-ulasphaeridia reticulata. The other characteristic formsare Sentusidinium granulatum, Dingodinium spp.,Chlamydophorella sp., Sirmiodinium grossii, Fromeafragilis, Lithodinia sp., Nelchinopsis kostromiensis,Microdinium ornatum Cookson et Eisenack, Jansoniaspp., Tubotuberella rhombiformis, Circulodiniumcompta (Davey) Helby, and Oligosphaeridium ?asteri-gium. The subfamily Pareodinioideae is not diverse,represented only by species of the genus Pareodinia.

Lower boundary is defined at the level of a consid-erable diversity decline (Borehole Severo-Vologochan-skaya 18). Disappearing above this level are generaCribroperidinium, Wallodinium, and species Occi-sucysta wiersbovskii, Tubotuberella apatela, Sirmiod-iniopsis orbis, Pluriarvalium osmingtonense and someothers.

Remarks. Dinocysts of the assemblage representmostly taxa of wide stratigraphic ranges, and the zoneis dated with reference to results of micropaleontologi-cal analysis (Nikitenko et al., 2004). Nevertheless, dataon dinocysts reliably determine position of the lowerboundary (Pestchevitskaya, 2005b), whereas the upperone is tentatively defined at the section top.

Type section: Borehole Severo-Vologochanskaya18, depth interval 909.6–842.3 m of recovered graysandy to clayey aleurites with interlayers of clay, sider-itic sandstone and aleurolite; thickness 67.3 m.

Distribution: Ust-Yenisei region (upper part of theSukhaya Dudinka Formation).

Stratigraphic position: upper part of the lower Val-anginian, upper Valanginian, and probably basal Hau-terivian.

Aldorfia sibirica–Aprobolocysta galeata Zone(DZ4, Figs. 2, 5)

Characteristic taxa. Dominant taxa are Dingodin-ium spp. (up to 5%) and D. cerviculum (up to 5.5%)occurring in association with stratigraphically impor-

tant species Nelchinopsis kostromiensis, Cassiculas-phaeridia reticulata, Oligosphaeridium complex, Din-godinium cerviculum, Sepispinula ?“huguoniotii”(Cookson et Eisenack) Islam, Aldorfia sibiricaPestchevitskaya, Aprobolocysta galeata, Gardodiniumsp., and Trichodinium speetonense. Persistent presenceof Sirmiodinium grossii, Pareodinia spp., Circulodin-ium spp., Cleistosphaeridium spp., and Oligosphaerid-ium spp. is characteristic.

Lower boundary defined in sections of the NordvikPeninsula and Anabar Bay eastern coast is not very dis-tinct, marked by the grown abundance of Dingodiniumcerviculum although not persistently. Aldorfia sibiricaappears at this level in the Anabar section, Aprobolo-cysta galeata in the Nordvik peninsula.

Remarks. In West Siberia (Borehole Roma-novskaya 140), Aprobolocysta galeata appears lower,in upper part of the Euryptychites quadrifidus Zoneprobably because of southerly position of the section.In the Moscow syneclise and northwestern Europe, thistaxon regularly occurring in the Hauterivian isunknown from underlying deposits (Iosifova, 1996;Prössl, 1990). A considerable abundance rate of D. cer-viculum is characteristic of the upper Valanginian in theSubpolar Urals (Lebedeva and Nikitenko, 1998). It isremarkable that the assemblage consists predominantlyof the Cretaceous taxa.

Upper boundary is not established, being tentativelydefined at the section top.

Type section: eastern coast of the Anabar Bay,Exposure 1A, beds 16–21; beds 16–18 are composed ofgray clayey to sandy-clayey aleurites with calcareousconcretions, Bed 19 corresponds to gray clayey sand-stone with calcareous concretions, Bed 20 to sandyaleurite with lenticular sand interlayers, Bed 21 to graycross-bedded sandstone; total thickness 29.7 m (Bogo-molov et al., 1983; Bogomolov, 1989).

Distribution: Khatanga depression (upper part ofthe Paksa Formation).

Stratigraphic position: lower Valanginian, Siber-ites ramulicosta Zone (upper part of the ramulicostaSubzone and lower part of the beani Subzone); estab-lished based on direct correlation with the Boreal stan-dard zones in sections of the Nordvik Peninsula (Basovet al., 1970; Zakharov et al., 1983; Bogomolov, 1989)and the Anabar Bay eastern coast (Zakharov et al.,1983; Bogomolov, 1989).

Hystrichodinium solare–Muderongia spp. Zone(DZ5, Figs. 2, 5)

Characteristic taxa. Persistent components of theassemblage are Dingodinium spp., Oligosphaeridiumspp., Muderongia spp., Sentusidinium spp.,Escharisphaeridia spp., Batioladinium spp., Cribrope-ridinium spp., Cleistosphaeridium spp., Jansonia spp.,and abundance of the first three species may be signifi-cant. The other characteristic forms are Muderongia



staurota Sarjeanti, M. tetracantha (Gocht) Alberti,M. simplex, M. pariata Duxbury, M. australis (up to9%), M. “tomaszowensis” Alberti emend. Riding et al.,M. brevispinosa Iosifova, Nelchinopsis kostromiensis,Batioladinium varigranosum, Oligosphaeridium com-plex, Aprobolocysta sp., Tenua ?americana (Pothe deBaldis et Ramos) Prössl, Gardodinium trabeculosum,and Cassiculasphaeridia reticulata. Stratigraphicallyimportant features are the diversity of the genus Mud-erongia and first occurrence of Hystrichodinium solarePestchevitskaya.

Lower boundary is defined tentatively at the firstoccurrence level of Hystrichodinium solare and theincreased diversity and abundance of the genus Mud-erongia (there is a hiatus in exposures of the NordvikPeninsula and the borehole section Gorshkovskaya1017 has not been sampled with gaps).

Remarks. The diversity of the genus Muderongiaand occurrence of Hystrichodinium solare are charac-teristic of the lower Hauterivian dinocyst assemblagesfrom the Subpolar Urals (Lebedeva and Nikitenko,1998). In Australia (Helby et al., 1987) and northernEurope (Aarhus et al., 1990; Nøhr-Hansen, 1993), per-sistent occurrence of Muderongia australis and itsabundance in particular have been observed beginningfrom the Hauterivian.

The upper boundary of beds with DZ5 is definedconventionally at the section top in the Nordvik Penin-sula: in borehole Gorshkovskaya 1017 there is a sam-pling gap (Fig. 2).

Type section: Nordvik Peninsula, Exposure 36, Bed11 of gray silty sandstones 4 m thick (Zakharov et al.,1983).

Distribution: Khatanga depression (lower part ofthe Tigyan Formation) and around latitudinal segmentof the Ob River (upper part of the Akh Formation).

Stratigraphic position: lower Hauterivian, middlepart of the Homolsomites bojarkensis Zone; establishedbased on direct correlation with the Boreal standardzones in section of the Nordvik Peninsula (Zakharovet al., 1983).

Aptea anaphrissa–Oligosphaeridium aff.totum–Batioladinium longicornutum Zone

(DZ6, Figs. 2, 5)

Characteristic taxa: Dinocyst diversity increases.In addition to taxa of wide stratigraphic ranges(Escharisphaeridia spp., Leberidocysta spp., Cassicu-lasphaeridia magna, Chlamydophorella spp., Jansoniaspp., Oligosphaeridium spp., Circulodinium spp., Cleis-tosphaeridium spp.), the assemblage constantly includesCassiculasphaeridia reticulata, Oligosphaeridium com-plex, Batioladinium varigranosum, and B. longicornu-tum (Alberti) Brideaux. Diversity of the genus Mud-erongia spp. increases (M. tetracantha, M. australis,M. endovata Riding et al., M. simplex, M. mcwhaeiCookson et Eisenack, M. staurota). The very character-

istic is presence of Nelchinopsis kostromiensis, Hystri-chodinium solare, H. voigtii (Alberti) Davey, H. pul-chrum Deflandre, Oligosphaeridium ?asterigium,O. cf. intermedium Corradini, Spiniferites ramosus,Achomosphaera neptunii, Aprobolocysta spp., Gardod-inium trabeculosum, and Tenua ?americana. Firstoccurrences of Pseudoceratium sp., Aptea anaphrissa(Sarjeant) Sarjeant et Stover, Batioladinium longicor-nutum, and Oligosphaeridium aff. totum Brideaux arestratigraphically important.

Lower boundary is conventionally defined in bore-hole section Gorshkovskaya 1017 at the beginning ofinterval 2656–2642 m (above the missing core interval,Fig. 2). The characteristic dinocyst assemblage getssuddenly the greater diversity at this level, and Oli-gosphaeridium aff. totum, Aptea anaphrissa, Batiola-dinium longicornutum, and single Pseudoceratium sp.appear here.

Remarks. In northern areas of western Europe, theoldest occurrence level of Aptea anaphrissa is estab-lished in upper part of the lower Hauterivian (Aarhuset al., 1990). Morphologically similar dinocysts presentas well in the lower Hauterivian assemblages ofmicrophytoplankton in the Subpolar Urals (Lebedevaand Nikitenko, 1998). The diversity of the genusPseudoceratium are characteristic of the upper Hau-terivian and Barremian of Canada (Bujak and Williams,1978) and several northern regions of Europe (Prössl,1990; Nøhr-Hansen, 1993; Iosifova, 1996; Smelroret al., 1998). Data on their occurrence in Lower Creta-ceous of Siberia have not been published, but accordingto oral communication of A.F. Fradkina, dinocysts ofthis genus are found in Hauterivian deposits of centralWest Siberia.

Type section: Borehole Gorshkovskaya 1017, inter-val 2656–2630.55 m of argillaceous deposits; thickness25.45 m.

Distribution: region of the Ob River latitudinal seg-ment (lower part of the lower Cherkashino Subforma-tion).

Stratigraphic position: upper part of the lowerHauterivian.

Aprobolocysta eilema–A. neista–Odontochitina spp. Zone (DZ7, Figs. 2, 5)

Characteristic taxa: Dinocyst diversity is increasedfurther. Dominant species are Escharisphaeridia spp.and Muderongia spp. Common species are Sentusidin-ium spp., Fromea spp., Mendicodinium spp., Leberi-docysta spp., Dingodinium spp., D. cerviculum, Cassic-ulasphaeridia magna, Jansonia spp., Apteodiniumspp., Aptea anaphrissa, and Circulodinium spp. Fre-quently occurring forms are Cassiculasphaeridia retic-ulata, Pareodinia spp., Odontochitina spp., O. opercu-lata (O. Wetzel) Deflandre et Cookson, and Hystri-chodinium spp. (H. voigtii, H. pulchrum). Verycharacteristic is diversity of genera Aprobolocysta,

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PESTCHEVITSKAYA

Pseudoceratium, Muderongia, and Batioladinium rep-resented by the following taxa: Aprobolocysta galeata,A. neista Duxbury, A. eilema Duxbury, A. cornutaPestchevitskaya, Pseudoceratium cf. pelliferum Gocht,P. expolitum Brideaux, Muderongia tetracantha,M. simplex, M. staurota, M. extensiva Duxbury,M. mcwhaei (up to 2%), M. “tomaszovensis,” M. cru-cis (up to 2%), M. australis, M. asymmetrica Aarhus,Batioladinium ?exiguum (Alberti) Brideaux, B. vari-granosum, B. jaegeri (Alberti) Brideaux, B. longicor-nutum (Alberti) Brideaux, and B. reticulatum Stover etHelby. Important species are Wrevittia helicoidea,Nelchinopsis kostromiensis, Oligosphaeridium com-plex, Vesperopsis mayi Bint, V. fragilis (Harding) Har-ding, Gardodinium trabeculosum, G. ordinale Davey,Gonyaulacysta ?kleithria Duxbury, Cyclonepheliumintonsum Duxbury, and Cymososphaeridium ?phoenix(Duxbury) Fauconni.

Lower boundary. Taxonomic composition ofdinocysts changes to a considerable extent at thisboundary that marks the diversity increase in generaAprobolocysta, Muderongia, and Batioladinium. Theboundary is marked by first occurrences of Odonto-chitina Dux, O. operculata, Aprobolocysta neista, A.eilema, A. cornuta, Pseudoceratium expolitum, Gon-yaulacysta ?kleithria, and Cyclonephelium intonsum;species Vesperopsis spp., V. mayi, and V. fragilis appearsomewhat higher. Dingodinium spp., D. cerviculum,and Mendicodinium spp. become commonly occurring,whereas Hystrichodinium solare, Tenua americana,Oligosphaeridium aff. totum, O. ?asterigium, Chlamy-dophorella spp. Disappear from the assemblage. Spe-cies of the genus Oligosphaeridium are of a lesserdiversity and do not occur regularly in the assemblage.

Remarks. Single specimens of Odontochitina oper-culata have been found in the upper Valanginian ofArctic Canada (Davies, 1983). This species occursmore frequently in the upper Hauterivian of northwest-ern Europe and Australia (Helby et al., 1987; Aarhus etal., 1990; Prössl, 1990). Diversity and persistent occur-rence of the genus Odontochitina is established in theBarremian deposits of Canada and northern Europe,where its species are sometimes fairly abundant (Bujakand Williams 1978; Davey, 1979; Duxbury, 1980, 2001;Aarhus et al., 1986; Nøhr-Hansen, 1993; Iosifova,1996; Nøhr-Hansen, McIntyre, 1998; Smelror et al.,1998). Constant presence and diversity of Pseudocera-tium forms is typical of the upper Hauterivian and Bar-remian dinocyst assembalges (Bujak and Williams,1978; Prössl, 1990; Nøhr-Hansen, 1993; Iosifova,1996; Smelror et al., 1998). In northwestern Europe,first occurrence of Aprobolocysta neista is detected inmiddle part of the lower Hauterivian (Davey, 2001),whereas A. eilema appears at the base of the upper Hau-terivian (A Stratigraphic…, 1992; Duxbury, 1977,2001). In northern areas of Germany, disappearancelevel of Tenua ?americana corresponds to the boundarybetween substages (Prössl, 1990). Oldest specimens ofVesperopsis fragilis have been found at the same level

(Harding, 1986). Species Pseudoceratium expolitum,Gonyaulacysta ?kleithria, Cyclonephelium intonsum,Gardodinium ordinale, and Vesperopsis mayi, whichare present in zone DZ7, are widespread and persis-tently occurring in the Barremian, being abundantsometimes (Nøhr-Hansen, 1993; Iosifova 1996; Smel-ror et al., 1998).

Upper boundary has not been observed. It wasimpossible to study compositional changes of dinocystsfrom transition between DZ7 and overlying subdivisionbecause of sampling gap (Fig. 2).

Type section: Borehole Gorshkovskaya 1017, inter-val 2630.55–2615 m of argillites; thickness 15.55 m.

Distribution: region of the Ob River latitudinal seg-ment (lower Cherkashino Subformation, upper part).

Stratigraphic position: lower part of the upperHauterivian.

Canningia spp.–Nelchinopsis kostromiensis Zone (DZ8, Figs. 2,5)

Characteristic taxa. Diversity of dinocysts issharply decreased. Dominant taxa are Escharisphaeridiaspp. and Mendicodinium spp. Common taxa are Leberi-docysta spp. and Canningia spp. Single specimens ofWallodinium sp., W. krutzschii, Endoscrinium sp.,Ovoidinium sp., Batioladinium spp., B. ?exiguum,Aprobolocysta spp., A. galeata, A. eilema, A. cornuta,Apteodinium spp., Nelchinopsis kostromiensis, Cyclo-nephelium intonsum, and Sentusidinium spp. are identi-fied as well.

Lower boundary has not been observed because ofincomplete core recovery and is defined tentativelybased on occurrence of the characteristic dinocystassemblage that is of sharply declined diversity. All thespecies of genera Muderongia, Hystrichodinium, Oli-gosphaeridium, Vesperopsis, Cassiculasphaeridia,Odontochitina, Pseudoceratium, and Gardodinium dis-appear from the assemblage along with Apteaanaphrissa, Cyclonephelium intonsum, Wrevittia heli-coidea, and other forms.

Remarks. Decreasing abundance and diversity ofmicrophytoplankton could be to a consequence of gen-eral regression in the West Siberian paleobasin (Pale-olandscapes…, 1968; Gol’bert, 1987).

Dinocysts are represented mostly by taxa of widestratigraphic ranges. The highest occurrence ofAprobolocysta eilema and Nelchinopsis kostromiensisis known in northwestern Europe up to the basal Barre-mian only, being unknown from higher strata(A Stratigraphic…, 1992; Nøhr-Hansen, 1993; Smelroret al., 1998; Aarhus et al., 1990). Upper boundary hasnot been observed.

Type section: Borehole Gorshkovskaya 1017, inter-val 2343–2330 m of argillites with insignificant inter-layers of silty argillites; thickness 13 m.



Distribution: region of the Ob River latitudinal seg-ment (upper Cherkashino Subformation, lower part).

Stratigraphic position: lower part of the lowerBarremian.

COMPARATIVE ANALYSIS OF LOWER CRETACEOUS DINOCYST ASSEMBLAGES

FROM SIBERIA, CANADA AND NORTHERN AREAS OF EUROPE

The lower Cretaceous dinocyst zonations are elabo-rated for the Subpolar Urals, Greenland, and northernregions of Europe and Canada. Successions of dinocystzones are established for separate regions and general-ized scale is suggested for Canada and northwesternEurope (Table 1). In respective works, principal atten-tion is paid to boundaries of biostratigraphic units andto consideration of criteria, which define with confi-dence stratigraphic positions and ranges of dinocystzones. In majority of works, these zones are distin-guished based on changes in taxonomic composition ofdinocyst assemblages, i.e., on first or last occurrencesof certain taxa and on their acme in particular sections,which are commonly of local significance. Strati-graphic ranges of the same taxa in other regions aresometimes omitted from considerations, and conse-quently their stratigraphic significance is improperlyevaluated. Accordingly, only some of them can beregarded as appropriate for determination of bound-aries between dinocyst zones: the appearance level ofsuch species in the section corresponds to their oldestoccurrence or their inceptions can be recognized at thesame level in different regions (Table 1). As a result,boundaries of concurrent biostratigraphic units aredefined sometimes based on different criteria. In such acase, correlation is possible by means of comparativeanalysis of general taxonomic composition of micro-phytoplankton assemblages. This laborious approach iscertainly inappropriate for correlation of palynostrati-graphic units of a narrow extent, but for a wider strati-graphic interval it is possible to define a group of char-acteristic species occurring in most regions of NorthEurasia and America. The Lower Cretaceous dinocystassemblages from northern regions of Siberia containquite a number of respective species (Table 2). In gen-eral, they appear in lower stratigraphic intervals and,being widespread Lower Cretaceous, define the “face”of corresponding assemblage.

The general tendency by transition from the Berria-sian to Hauterivian consists in growing significance ofchorate dinocysts, species of the family Ceratiaceae,and in compositional changes of the family Pareodini-aceae (Table 2). The Berriasian dinocyst assemblagesmost similar to assemblages of North Siberia aredescribed from the Boyarka River sections (theYenisei–Khatanga depression; Fedorova et al., 1993),Subpolar Urals (Fedorova et al., 1993; Lebedeva andNikitenko, 1998), and Moscow basin (Iosifova, 1996).The situation changes in the Valanginian: dinocyst

assemblages from nearby (Subpolar Urals, Moscowbasin) and remote regions (western Europe, Canada,Greenland) contain many species in common, exceptfor sections of the Barents Sea shelf, where Berriasianand Valanginian assemblages contain each only onetaxon occurring in the studied Siberian sections (Table 2).Similarity between North Siberian and Canadiandinocyst assemblages decreases in Hauterivian depos-its. The most different are the assemblages from ArcticCanada.

The Barremian assemblages of dinocysts fromnorthern regions of Siberia are of a low taxonomicdiversity. In the Barremian Age, area of the West Sibe-rian paleobasin became considerably reduced (Pale-olandscapes…, 1968; Gol’bert, 1987), and the assem-blages likely consisted of taxa, which were able to sur-vive unstable environments in the habitat basin, wheredepths and salinity often changed. In Europe, the Bar-remian dinocyst assemblages are known from sectionsof normal marine facies, and accordingly theirdinocysts are extraordinary abundant and diverse (Aar-hus et al., 1990; Prössl, 1990; Smelror et al., 1998;Duxbury et al., 1999; Duxbury, 2001).

It is remarkable that concurrent dinocyst assem-blages from northern regions of Eurasia and Americacontain species in common, which are informative interms of stratigraphy, because their first occurrence isconfined to particular level in different regions. Theoldest specimens of a certain species are usually knownfrom one region, whereas in the other sections thistaxon can be found in higher horizons (Table 3). On theother hand, there is a series of species whose first or lastoccurrence is recorded practically at the same level inseveral northern regions of Eurasia and America(Table 3). These species exactly are regarded in thiswork as palynological criteria determining boundariesof biostratigraphic units in Siberian succession ofdinocyst assemblages (Table 4). It is remarkable there-with that the dinocyst zones distinguished in the upperBerriasian, Valanginian and lower Hauterivian of NorthSiberia are directly correlated with the Boreal standardzonations (Zakharov et al., 1997), being studied in stra-totype sections of the Khatanga depression. Conse-quently, boundaries of the North Siberian dinocystzones are important stratigraphic markers in most casesowing to this correlation.

As dinocyst zones are defined based on inceptionsand extinctions of species at certain stratigraphic levelsnot only in Siberia, but also in the other northernregions of Eurasia, their boundaries are recognizableover vast territories (Fig. 5, Table 4). In some cases, itis possible therefore to correlate directly the dinocystbiostratigraphic subdivisions of North Siberia withunits of dinocyst zonations in Western Europe and Can-ada.

The Berriasian and two lower Valanginian levels arerecognizable in northern regions of Canada, Europeand Siberia (Fig. 5, Table 4). The first occurrence of

594


PESTCHEVITSKAYA

Tab

le 1

. Cor

rela

tion

of L

ower

Cre

tace

ous

dino

cyst

zon

atio

ns e

stab

lishe

d in

nor

ther

n re

gion

s of

Eur

asia

and

Am

eric

a

Stage Barremian Hauterivian Valanginian BerriasianSubstage lower

Sout

heas

tern

Apt

ea a

naph

riss

aPe

ak Z

one

LB

: fir

st o

ccur

renc

e of

Cte

nido

dini

um e

lega

ntum

LB

: firs

t occ

urre

nce

of C

ircu

-

asym

met

ricu

m, S

urcu

losp

-

Phob

eroc

ysta

LB

: firs

t occ

urre

nce

of P

hobe

-

nium

ele

gant

um, C

ircu

lo-

Eas

tern

Apt

ea

LB

: acm

e –

Ap-

Cte

nido

dini

um

Pho

bero

cyst

a

LB

: fir

st o

ccur

ren-

Arc

tic C

anad

a

?

Val

vaeo

dini

um a

tlant

icum

Opp

el Z

one.

LB

: fir

st

Elli

psoi

dict

yum

cin

ctum

, Esc

hari

spha

erid

ia r

udis

,

Mud

eron

gia

sim

plex

Opp

el Z

one

Tan

yosp

haer

idiu

m m

agne

ticum

Opp

el Z

one

LB

: fir

st o

ccur

renc

e of

T. m

agne

ticum

, Apt

eod-

glut

inat

a, L

. epi

som

um, M

. tom

aszo

wen

sis,

O.

Cyc

lone

phel

ium

cuc

ullif

orm

e –

LB

: fir

st o

ccur

renc

e of

Cyc

lone

phel

ium

Tric

hodi

nium

eri

nace

oide

s –

New

foun

dlan

d

Van

Hel

den,

198

6

?

Pho

bero

cyst

a ne

ocom

ica

Ass

embl

age

Zon

e

End

oscr

iniu

m c

ampa

nula

A

ssem

blag

e Z

one

LB

: fir

st o

ccur

renc

e of

Bat

io-

Can

tulo

dini

um a

rthu

riae

,

Am

phor

ula

met

aelli

ptic

a A

ssem

blag

e Z

one

LB

(th

e Po

rtla

ndia

n ba

se),

Jenk

ins

Apt

ea

acm

e of

Ctenidodinium

Pho

bero

cyst

a

upper middleupper lower upper lower lowerupperC

anad

a(B

ujak

et W

illia

ms,

197

8)

Apt

ea p

olym

orph

a,A

. ana

phri

ssa

(acm

e),

Pse

udoc

erat

ium

re-

gium

;la

st o

ccur

renc

e of

R

hync

hodi

niop

sis

serr

ata

Ass

embl

age

Zon

e

lodi

nium

atta

dalic

um, C

yc-

lone

phel

ium

van

noph

orum

,C

ribr

oper

idin

ium

ort

hoce

-ra

s, C

alai

osph

aeri

dium

haer

idiu

m ?

long

ifurc

atum

,Su

btili

spha

era

perl

ucid

a;la

st o

ccur

renc

e of

B. j

oh-

new

ingi

, I. k

ondr

atje

vi

neoc

omic

a A

ssem

blag

e Z

one

rocy

sta

neoc

omic

a, B

iorb

i-fe

ra jo

hnew

ingi

, Ach

omo-

spha

era

nept

unii,

Cor

oni-

fera

oce

anic

a, C

teni

dodi

-

dini

um d

istin

ctum

, Rhy

n-ch

odin

iops

is s

erra

ta, L

i-th

osph

aeri

dium

sip

honi

-ph

orum

Can

ada

(Will

iam

set

al.,

197

4)

anap

hris

saPe

ak Z

one

tea

anap

hiri

ssa,

Subt

ilisp

haer

ape

rluc

ida

eleg

antu

m–

Pse

udoc

erat

ium

pelli

feru

mZ

one

neoc

omic

aZ

one

ce o

f P

hobe

ro-

cyst

a ne

ocom

ica,

Ach

omos

phae

rane

ptun

ii,Sy

stem

atop

hora

com

plic

ata

(Dav

ies,

198

3)

occu

rren

ce o

f V

. atla

ntic

um; l

ast o

ccur

renc

e of

A

pteo

dini

um a

piat

um, B

atia

casp

haer

a ag

glut

inat

a,

S. c

ryst

allin

um, P

rolix

osph

aeri

dium

spi

ssum

, Lep

-to

dini

um e

piso

mum

, C. c

ucul

lifor

me,

T. r

hom

bifo

rmis

?

iniu

m a

piat

um, C

ribr

oper

idin

ium

mud

eron

gens

e,K

allo

spha

erid

ium

?ci

rcul

are,

Bat

iaca

spha

era

ag-

albe

rten

se, O

. com

plex

, O. t

otum

, O. o

perc

ulat

a

Par

agon

yaul

acys

ta b

orea

lis O

ppel

Zon

e

Tetr

acha

cyst

a sp

inos

igib

erro

saO

ppel

Zon

e

ladi

nium

var

igra

nosu

m, N

el-

chin

opsi

s ko

stro

mie

nsis

; las

toc

curr

ence

of

Am

phor

ula

me-

tael

liptic

a, A

. del

icat

a,

Sent

usid

iniu

m r

ioul

tii

pres

ence

of

C. a

rthu

riae

,A

mph

orul

a m

etae

llipt

ica,

A.

delic

ata,

Sen

tusi

dini

um r

ioul

tii

et a

l., 1

974

anap

hris

sape

ak Z

one

Apt

ea

anap

hris

sa

elegantum Zone

neoc

omic

a Z

one

pres

ence

of

P. n

eoco

mic

a,P

seud

ocer

ati-

um n

udum

,Sp

rini

feri

tes

dent

atus

,A

. nep

tuni

i,Sy

stem

ato-

phor

aor

bife

ra

Biorbifora johnewingi

Art

hur

Phoberocysta neocomica ZoneApteodinium

Cte

nido

-

Eas

t Eng

land

LB

Zon

e (?

)

Can

ning

iops

is “

tabu

lata

”

Zon

e E

LB

: fir

st o

ccur

renc

e of

Zon

e D

LB

: fir

st o

ccur

renc

e of

Wre

-

Zon

e C

LB

: fir

st o

ccur

renc

e of

sis

scal

a ap

pear

in th

e

Zon

e B

LB

: fir

st o

ccur

renc

e of

Zon

e A

: fir

st o

ccur

renc

e of

um e

vitii

, Pap

uadi

nium

Sout

h E

ngla

nd

Am

mo-

bide

n-

rude

nc-

eleg

ans

fissi

cos-

raro

cin-

vari

a-

mar

gi-

gotts

-

spee

to-

inve

rsus

rega

le

nori

cum

ambl

y-

Din

ocys

t zon

es

Odontochitina

Pal

aeop

erid

iniu

m

Apt

ea a

naph

riss

a

Cas

sicu

lasp

haer

idia

Subtilisphaera

Nex

osis

pini

um

Can

ning

ia

Discorsia nanna

Bat

iola

dini

um

Kle

ithri

asph

aeri

dium

Not

es: (

LB

) lo

wer

bou

ndar

y; (

UB

) up

per

boun

dary

; str

atig

raph

ical

ly im

port

ant t

axa

liste

d in

the

tabl

e ar

e pr

inte

d in

bol

d, if

thei

r fi

rst o

r la

st o

ccur

renc

e is

rec

orde

d at

the

give

n le

vel

in d

iffe

rent

reg

ions

, and

in r

egul

ar ty

pe, i

f in

the

desi

gnat

ed s

ectio

n on

ly.

Subzone

et a

l., 1

982

? nuciformeZone

dini

umpa

nneu

mZ

one

(Dux

bury

, 197

7)

appe

ars

in u

pper

par

t

Subt

ilisp

haer

a te

rrul

a

vitti

a pe

rfor

obtu

sa; A

prob

o-lo

cyst

a ei

lem

a ap

pear

sin

the

uppe

r H

aute

rivi

an

Olig

osph

aeri

dium

com

plex

,Sp

rini

feri

es r

amos

us s

ubsp

.pr

imae

vus;

Dis

cors

ia

nann

a an

d N

emat

osph

aero

p-

mid

dle

Hys

tric

hodi

nium

furc

atum

app

ears

at t

heH

aute

rivi

an b

ound

ary

K. e

inoi

des;

last

occ

urre

nce

of P

apua

dini

um a

picu

latu

m

Occ

isuc

ysta

tent

oriu

m, W

re-

vitti

a ?d

iutin

a, E

ndos

crin

i-um

cam

panu

la, C

ircu

lodi

ni-

um d

istin

ctum

, Teh

amad

ini-

apic

ulat

um

(Har

ding

, 198

6)

noid

zo-

nes

cret

acea

Subz

one

operculata Zone

Subz

one

mag

na S

ubzo

ne

vetu

scul

um s

ubzo

ne

cf. r

etic

ulat

aSu

bzon

e

terrula Zone Zone

?

long

icor

nutu

mSu

bzon

e

sim

plic

ispi

num

Subz

one

tatu

m

kman

i

tatu

m

ctum

bilis

natu

s

chei

nens

is

goni

um

cucu

lifor

me



Tab

le 1

. (C

ontd

.)E

ngla

nd, N

orth

Sea

Dux

bury

, 200

1

Am

mo-

bide

nta-

rude

nck-

eleg

ans

fissi

cost

a-

raro

cinc

-

vari

abili

s

mar

gina

-

gotts

chei

spee

to-

inve

rsus

rega

le

nori

cum

ambl

ygo-

unna

med

pitr

ei

dich

oto-

poly

pty-

para

tolli

a

albi

dum

sten

om-

icen

ii

koch

i

runc

toni

Din

ocys

t zon

es

LK

P22

Zon

e; L

B: l

ast o

ccur

renc

e of

Apr

obol

ocys

ta n

eist

a

LK

P19

Zon

e; f

irst

occ

urre

nce

of A

chom

osph

aera

ram

ulife

ra,

LK

P17.

2 Su

bzon

e; L

B: l

ast o

ccur

renc

e of

Nel

chin

opsi

s

LK

P17.

1 Su

bzon

e; L

B: l

ast o

ccur

renc

e of

Des

moc

ysta

LK

P16.

1 Su

bzon

e; L

B: l

ast o

ccur

renc

e of

Olig

osph

aeri

-

LK

P15

Zon

e; L

B: a

cme

of O

ligos

phae

ridi

um ju

nctu

m

LK

P14

Zon

e; L

B: a

cme

of C

ymos

osph

aeri

dium

val

idum

LK

P13

Zon

e; L

B: a

cme

of H

. arb

oris

pinu

m

LK

P9 Z

one;

Zon

e; L

B: l

ast o

ccur

renc

e of

Spi

nife

rite

s

LK

P8 Z

one;

LB

: las

t occ

urre

nce

of S

yste

mat

opho

ra

7.2

Subz

one;

LB

: las

t occ

urre

nce

of S

pini

feri

tes

?spo

n-

7.1

Subz

one;

last

occ

urre

nce

of A

prob

oloc

ysta

ext

rem

a

LK

P6 Z

one;

LB

: las

t occ

urre

nce

of D

ingo

dini

um ?

spin

osum

;

Raw

son,

Rile

y,

Sirmiodinium

Pla

eope

ridi

-

Apt

ea

Kle

ithri

asph

ae-

Subt

ili-

N. v

etus

culu

mC

anni

ngia

cf.

Discorsia nanna Zone

GardodiniumK

leith

rias

phae

-

Phoberocysta neocomica Zone

Tubo

tube

rella

Dingodinium ?spinosum Zone

Egm

onto

dini

-

Dic

hado

go-

Can

nosp

hae-

Dux

bury

et a

l., 1

999

?

noid

zo

nes

Stage Barremian Hauterivian Valanginian BerriasianSubstage lowerupper middleupper lower upper lower loweruppermiddletu

m

man

i

tum

tum

tus

nens

is

nium

mite

s

phal

us

chite

s

LK

P25

Zon

e; L

B: l

ast o

ccur

renc

e of

Cri

brop

erid

iniu

m c

ornu

tum

,Sc

rini

odin

ium

bar

rem

ianu

m;

UB

: Hys

tric

hodi

nium

ram

oide

s

LK

P25

Zon

eL

KP2

4 Z

one

LK

P23

Zon

e

last

occ

urre

nce

of A

scod

inum

fiss

ilum

LK

P18

Zon

e; a

cme

of A

ptea

ana

phri

ssa

LK

P20

Zon

e, L

KP2

1 Z

one

kost

rom

iens

is

sim

plex

, Can

ning

ia d

uxbu

ry

LK

P16.

2 Su

bzon

e

dium

junc

tum

; fir

st o

ccur

renc

e of

Apr

obol

ocys

taei

lem

aLKP16 ZoneLKP17

LK

P12

Zon

e

LK

P10

Zon

eL

KP1

1 Z

one

palm

ula

LKP7Zone

gios

us, S

yste

mat

opho

ra s

cori

acea

Olig

osph

aeri

dium

com

plex

app

ears

insi

de z

one

?

1982

grossii Zone

nium

cre

tace

aSu

bzon

e

anap

hris

saSu

bzon

e

ridi

um c

orru

-ga

tum

Sub

zone

spha

era

terr

ula

Zon

ere

ticul

ata

Subz

one

trabeculosumSubzone

apat

ela

Subz

one

um to

ryna

Subz

one

ridi

um s

imp-

licis

pinu

m

rops

is s

p. A

Su

bzon

e

nyau

lax

spp.

Subz

one

Mud

eron

gia

exte

nsiv

aSu

bzon

e

LK

P5 Z

one.

UB

: las

t occ

urre

nce

of D

ingo

dini

-

Mud

eron

gia

sim

plex

(L

KP4

) Z

one.

LB

: las

t

LK

P3 Z

one.

LB

: las

t occ

urre

nce

of R

otos

phae

rop-

Rot

osph

aero

psis

thul

e (L

KP2

) Z

one

LB

: fir

st o

ccur

renc

e of

Dav

eya

bore

spha

era

Cir

culo

dini

um c

ompt

a (L

KP1

) Z

one

LB

: acm

e of

Cir

culo

dini

um c

ompt

a; la

st o

ccur

-

Can

ada,

?

Phoberocysta neocomica Zone

Mud

eron

gia

exte

nsiv

a

LB

: fir

st o

ccur

renc

e of

End

oscr

iniu

m p

haro

Sub

zone

LB

: las

t occ

urre

nce

of D

ingo

di-

Din

godi

nium

?sp

inos

umSu

bzon

eL

B: l

ast o

ccur

renc

e of

Dia

cant

h-

Occ

isuc

ysta

tent

oriu

m, E

ndo-

hesl

erto

nens

is; l

ast o

ccur

renc

e

Nor

thw

este

rn

Odontochitina operculata Zone

Pal

aeop

erid

iniu

m c

reta

ceum

Apt

ea a

naph

riss

a Su

bzon

e.L

B: a

cme

of A

ptea

ana

phri

s-

Cas

sicu

lasp

haer

idia

mag

na

Subtili-

Nex

osis

pini

um v

etus

-

Can

ning

ia c

f. r

etic

ulat

a

Can

ning

ia c

f. r

etic

ulat

a

Discorsia nanna

Gar

dodi

nium

trab

ecul

osum

LB

: acm

e of

Gar

dodi

nium

Kle

ithri

asph

aeri

dum

Spin

iferi

tes

ram

osus

LB

: fir

st o

ccur

renc

e of

Pse

udoc

erat

ium

pel

lifer

um Z

one

Pse

udoc

erat

ium

pel

life-

LB

: fir

st o

ccur

renc

e of

Pse

-

Gochteodinia villosa Zone

End

oscr

iniu

m p

haro

Sub

-

Can

nosp

haer

opsi

s sp

. A

LB

: las

t occ

urre

nce

of

Nor

thea

ster

n

Batioladinium longicornutum Zone

Pse

udoc

erat

ium

tove

ae

acm

e of

Pse

udoc

erat

ium

Apt

ea a

naph

riss

a Su

bzon

e.L

B: l

ast o

ccur

renc

e of

N. k

ostr

o-

Nel

chin

opsi

s

um ?

spin

osum

, Dic

hado

gony

aula

x cu

lmul

a

occu

rren

ce o

f Bat

iola

dini

um “

pom

um”

sis

thul

e; a

cme

of B

. rad

icul

atum

, O. d

ilucu

lum

renc

e of

C. g

igas

, Lep

todi

nium

arq

uatu

m

Nor

thw

este

rn E

urop

e(F

ishe

r et

Rile

y, 1

980)

Subz

one

Mud

eron

gia

exte

nsiv

a

nium

?sp

inos

um, P

apua

dini

umap

icul

atum

, Par

agon

yaul

acy-

sta

capi

llosa

, Cte

nido

dini

um?s

chiz

obla

tum

um h

ollis

teri

, Pap

uadi

nium

apic

ulat

um, B

iorb

ifera

john

e-w

ingi

, Egm

onto

dini

um to

ryna

, A

chom

osph

aera

nep

tuni

i,

scri

nium

cam

panu

la, P

hobe

-ro

cyst

a ne

ocom

ica,

Pse

udoc

e-ra

tium

pel

lifer

um, H

esle

rton

ia

of P

areo

dini

a an

tenn

ata

Eur

ope

(Dav

ey, 1

979)

Subz

one.

LB

: fir

st o

ccur

renc

eof

Car

podi

nium

gra

nula

tum

sa; l

ast o

ccur

renc

e of

N

exos

ispi

nium

vet

uscu

lum

Subz

one

sphaeraterrula

culu

m S

ubzo

ne

Subz

one

Subz

one.

L

B: f

irst

occ

urre

nce

ofSu

btili

spha

era

terr

ula,

Oph

iobo

lus

sp. A

Zone

Subz

one.

trab

ecul

osum

“sim

plic

ispi

num

”Su

bzon

e

Zon

e

Olig

osph

aeri

dium

com

plex

rum

Zon

e.

udoc

erat

ium

pel

lifer

um;

last

occ

urre

nce

of D

in-

god

iniu

m ?

spin

osu

m,

E. p

haro

zone

. LB

: las

t occ

urre

nce

of C

anno

spha

erop

sis

sp. A

Subz

one

Egm

onto

dini

um s

p. A

LB at the mid-Portlandian level(opressus)

Gre

enla

nd(N

ohr-

Han

sen,

199

3)

Subz

one

?

kost

rom

iens

isSu

bzon

e

mie

nsis

; acm

e of

A. a

naph

riss

a

prim

aevu

s

tove

ae

596


PESTCHEVITSKAYA

Stage Barremian Hauterivian Valanginian BerriasianSubstage lowerupper middleupper lower upper lower lowerupper

Tab

le 1

. (C

ontd

.)

Den

mar

k

?

Discorsia nanna

Bat

iola

dini

um lo

ngic

ornu

-

cum

, Hys

tric

hodi

nium

Spin

iferi

tes

ram

osus

Zon

e

LB

: fir

st o

ccur

renc

e of

Hys

tri-

Pse

udoc

erat

ium

pel

lifer

um

LB

: fir

st o

ccur

renc

e of

Pse

udo-

Gochteodinia villosa Zone

End

oscr

iniu

m p

haro

Sub

zone

LB

: las

t occ

urre

nce

of

Rot

osph

aero

psis

thul

e

LB

: fir

st o

ccur

renc

e of

Bat

iola

dini

-

Am

phor

ula

expi

rata

Sub

zone

Nor

thw

este

rn

Impa

gidi

nium

ale

ctop

horu

m Z

one

LB

: fir

st o

ccur

renc

e of

Ste

phod

i-

Cas

sicu

lasp

haer

idia

mag

na,

Exi

guis

phae

ra p

lect

ilis

Zon

e

LB

: fir

st o

ccur

renc

e of

Exi

guis

-

Cor

onife

ra o

cean

ica

Zon

e. L

B: a

c-

Bat

iola

dini

um lo

ngi-

LB

: fir

st o

ccur

renc

e of

Gon

yaul

acys

ta

Cym

osos

phae

ridi

um v

alid

um

?

Subp

olar

Ura

ls

amm

o-

vers

i-

boja

r- ramulosus

mic

hal-

insolutus

paye

ri analogus

koch

i

dino

cyst

zon

es

LB

: fir

st o

ccur

renc

e of

Hys

tri-

Con

tinen

tal

Tenu

a am

eric

ana–

Din

godi

nium

LB

: fir

st o

ccur

renc

e of

Mud

eron

gia

sim

plex

–Cri

bro

?

Din

godi

nium

?al

bert

ii–

LB

: fir

st o

ccur

renc

e of

Par

agon

yaul

acys

ta?b

orea

lis z

ones

Nor

th S

iber

ia, l

ower

Ammonoid

Can

ning

ia s

pp.,

Nel

chi-

UB

: las

t occ

urre

nce

of

Apr

obol

ocyt

a ei

lem

a,

LB

: fir

st o

ccur

renc

e of

Apr

obol

o-

Apt

ea a

naph

riss

a –

Olig

o-

LB

: fir

st o

ccur

renc

e of

Apt

ea

boja

rken

sis

Hys

tric

hodi

nium

sol

are,

LB

: fir

st o

ccur

renc

e of

bidi

hoto

mus

Ald

orfia

sib

iric

a,

(Dav

ey, 1

982)

Zone

tum

Sub

zone

. LB

: fir

st o

ccur

-re

nce

of T

anyo

spha

erid

i-um

bol

etum

, C

alla

iosp

ha-

erid

ium

cf.

asy

mm

etri

-

furc

atum

, Sta

nfor

della

ordo

cava

ta

chos

paer

idiu

m c

f. a

rbor

ispi

num

Zon

e

cera

tium

pel

lifer

um; l

ast o

ccur

-re

nce

of D

icha

dogo

nyau

lax

Rot

osph

aero

psis

thul

e

Subz

one

um p

omum

, Ald

orfi

a di

ctyo

ta

LB

(th

e up

per

Port

land

ian

base

): a

cme

of C

ircu

lo-

dini

um c

ompt

a

Ger

man

y(P

röss

l, 19

90)

nium

spi

nulo

sum

, Elli

psoi

dict

umre

ticul

atum

, Pro

toel

lipso

dini

umde

nsis

pinu

m; l

ast o

ccur

renc

e of

Pte

rodi

nium

pre

mno

s

phae

ra p

lect

ilis;

last

occ

urre

nce

of S

pini

fere

tis ?

mag

nose

rrat

us

me

of C

oron

ifera

oce

anic

a, C

anin

-gi

a pi

stic

a, M

uder

ongi

a te

trac

anth

a

corn

utum

Zon

e

teic

hos,

Apt

eodi

nium

com

ptum

Zon

e

(Leb

edev

a an

d N

ikite

nko,

199

8)

noid

zo-

nes

skii

kens

is

colo

r

depo

sits

Gar

dodi

nium

trab

ecul

osum

zon

es

cerv

icul

um z

ones

Ten

ua a

mer

ican

a

peri

dini

um m

uder

onge

nse

zone

s

Am

bono

spha

era

delic

ata

zone

s

Nel

chin

opsi

s ko

stro

mie

nsis

,A

mbo

nosp

haer

a de

licat

a

(LB

: upp

er p

art

of th

e up

per

Vol

gian

Sub

stag

e)

chod

iniu

m s

p. A

(so

lare

)

Ber

rias

ian

afte

r N

ikite

nko

et a

l.,00

4 up

to a

nalo

gus

and

high

er f

rom

this

wor

k

zones(Zakharov et al., 1997)

nops

is k

ostr

omie

nsis

zon

es

Nel

chin

opsi

s ko

stro

mie

nsis

, A

prob

oloc

ysta

eile

ma

? ? ?

DZ

8

DZ

7

DZ

6

Apr

obol

ocys

ta n

eist

a,O

dont

ochi

tina

spp.

zon

es

cyst

a ei

lem

a, O

dont

ochi

tina

oper

-cu

lata

and

Ves

pero

psis

fra

gi-

lis a

bit

high

er; a

st o

ccur

renc

e of

spha

erid

ium

aff

. tot

um –

Bat

io-

ladi

nium

long

icor

nutu

m z

ones

anap

hris

sa

Mud

eron

gia

spp.

zon

es

Hys

tric

hodi

nium

sol

are

Apr

obol

ocys

ta g

alea

ta z

ones

DZ

5

? ?

DZ

4

DZ

3

DZ

2

LB

: fir

st o

ccur

renc

e of

ram

ulic

osta

astie

ript

ychu

s

quad

rifid

us

Olig

osph

aeri

dium

com

plex

,

LB

: fir

st o

ccur

renc

e of

Olig

osph

a-

klim

ovsk

iens

isE

scha

risp

haer

idia

spp

.,

LB

: las

t occ

urre

nce

of

tolli

mes

ezni

kow

i

anal

ogus

koch

i

sibi

ricu

s

Paragonyaulacysta ?borealis–

DZ

1: P

areo

dini

oide

ae, B

atio

la-

LB

: fir

st o

ccur

renc

e of

Bat

iola

di-

Par

agon

yaul

acys

ta

Ald

orfia

sib

iric

a

Din

godi

nium

cer

vicu

lum

zon

es

erid

ium

com

plex

, D

ingo

dini

umce

rvic

ulum

Olig

osph

aeri

dium

spp

.,C

ircu

lodi

nium

spp

. zon

es

Par

agon

yaul

acys

ta ?

bore

alis

,

Dingodinium ?spinosum Zone

dini

um v

arig

rano

sum

, Cas

sicu

-la

spha

erid

ia r

etic

ulat

a zo

nes

nium

var

igra

nosu

m, C

assi

cu-

lasp

haer

idia

ret

icul

ata,

Tan

y-os

phae

ridi

um m

agne

ticum

capp

ilosa

– S

irm

iodi

niop

sis

orbi

s sp

p. z

ones

culm

ula

Ten

ua a

meric

an

a

Din

godi

nium

?sp

inos

um



Tab

le 2

. C

ompa

riso

n of

the

Low

er C

reta

ceou

s di

nocy

st a

ssem

blag

es f

rom

nor

ther

n re

gion

s of

Eur

asia

and

Am

eric

a

Stag

e,su

bsta

ge

Tax

a in

com

mon

with

din

ocys

ts f

rom

Nor

th S

iber

ian

sect

ions

Arc

tic C

anad

a (W

illia

ms

et a

l., 1

974;

Bid

eaux

, Fis

her,

197

6; B

ujak

, Will

iam

s, 1

978;

Dav

ies,

198

3)

Bor

eal C

anad

a (M

cInt

yre,

Bri

deau

x, 1

980;

Dav

ies,

198

3; V

an H

elde

n, 1

986;

Jen

kins

et a

l.,19

74)

Gre

enla

nd (

Pias

ecki

, 197

9; N

ohr-

Han

sen,

1993

, Hak

anss

on e

t al.,

198

1)

Low

er

Bar

rem

ian

Uns

tudi

edU

nstu

died

Uns

tudi

ed

Upp

er

Hau

teri

-vi

an

Pare

odin

ioid

eae:

Bat

iola

dini

um ja

eger

i;ot

her

prox

imat

e di

nocy

sts:

Wal

lodi

nium

luna

, Din

go-

dini

um c

ervi

culu

m;

chor

ate:

Oli

gosp

haer

idiu

m c

ompl

ex

Pare

odin

ioid

eae:

Bat

iola

dini

um ja

eger

i, B

. ?ex

iguu

m;

Cer

atia

ceae

: Pse

udoc

erat

ium

pel

life

rum

, Mud

eron

gia

sim

plex

;A

erol

iger

acea

e: C

ircu

lodi

nium

dis

tinc

tum

;ot

her

prox

imat

e: D

ingo

dini

um c

ervi

culu

m;

chor

ate:

Oli

gosp

haer

idiu

m c

ompl

ex

Prox

imat

e G

onya

ulac

oide

ae: C

ribr

oper

eidi

nium

con

-fo

ssum

, C. ?

edva

rdsi

i, St

anfo

rdel

la ?

cret

acea

;Pa

reod

inio

idea

e: B

atio

ladi

nium

jaeg

eri,

B. l

ongi

corn

u-tu

m;

Cer

atia

ceae

: Mud

eron

gia

sim

plex

, Pse

udoc

erat

ium

pel

-li

feru

m;

Aer

olig

erac

eae:

Cir

culo

dini

um d

isti

nctu

m;

chor

ate:

Oli

gosp

haer

idiu

m c

ompl

ex, H

ystr

icho

dini

um

voig

tii,

H. p

ulch

rum

, Gar

dodi

nium

trab

ecul

osum

, Cas

-si

cula

spha

erid

ia m

agna

Low

er

Hau

teri

-vi

an

Prox

imat

e di

nocy

sts:

Wal

lodi

nium

luna

;ch

orat

e fo

rms:

Oli

gosp

haer

idiu

m c

ompl

exC

erat

iace

ae: M

uder

ongi

a si

mpl

ex;

Aer

olig

erac

eae:

Cir

culo

dini

um d

isti

nctu

m;

chor

ate:

Oli

gosp

haer

idiu

m c

ompl

ex

Pare

odin

ioid

eae:

Bat

iola

dini

um ja

eger

i, B

. lon

gico

rnu-

tum

;C

erat

iace

ae: M

uder

ongi

a si

mpl

ex;

othe

r pr

oxim

ate:

Gar

dodi

nium

trab

ecul

osum

, Cas

sicu

-la

spha

erid

ia m

agna

;A

erol

iger

acea

e: C

ircu

lodi

nium

dis

tinc

tum

;ch

orat

e: O

ligo

spha

erid

ium

com

plex

, Hys

tric

hodi

nium

vo

igti

i, H

. pul

chru

m

Low

erV

alan

-gi

nian

Prox

imat

e G

onya

ulac

oide

ae: T

ubot

uber

ella

rho

m-

bifo

rmis

, Apt

eodi

nium

gra

nula

tum

, A. s

pong

iosu

m,

Wre

vitt

ia h

elic

oide

a, S

tanf

orde

lla

?cre

tace

a, N

el-

chin

opsi

s ko

stro

mie

nsis

, Hes

lert

onia

hes

lert

onen

sis,

Si

rmio

dini

um g

ross

ii, C

ribr

oper

idin

ium

?m

uder

on-

gens

e;Pa

reod

inio

idea

e: P

areo

dini

a ce

rato

phor

a, P

arag

on-

yaul

acys

ta ?

bore

alis

(at

the

base

);C

erat

iace

ae: C

ircu

lodi

nium

dis

tinc

tum

, Mud

eron

gia

sim

plex

;ot

her

prox

imat

e di

nocy

sts:

Wal

lodi

nium

luna

, Din

go-

dini

um c

ervi

culu

m;

chor

ate

dino

cyst

s: O

ligos

phae

ridi

um c

ompl

ex (

from

th

e ba

se o

f B

uchi

a ke

yser

ling

i Zon

e), O

. ?as

teri

gium

, O

. alb

erte

nse

Prox

imat

e G

onya

ulac

oide

ae: N

elch

inop

sis

kost

rom

ien-

sis,

Lit

hodi

na s

tove

ri;

pare

odin

ioid

eae:

Par

eodi

nia

cera

toph

ora,

Bat

iola

dini

-um

var

igra

nosu

m;

Cer

atia

ceae

: Mud

eron

gia

sim

plex

;ot

her

prox

imat

e: D

ingo

dini

um c

ervi

culu

m;

Aer

olig

erac

eae:

Cir

culo

dini

um d

isti

nctu

m;

chor

ate:

Olig

osph

aeri

dium

com

plex

(abo

ve th

e m

iddl

e),

O. ?

aste

rigi

um

Prox

imat

e G

onya

ulac

oide

ae: T

rich

odin

ium

cil

iatu

m,

Hes

lert

onia

hes

lert

onen

sis,

Tub

otub

erel

la a

pate

la,

Sirm

iodi

nium

gro

ssii

;Pa

reod

inio

idea

e: P

arag

onya

ulac

ysta

?bo

real

is (

near

th

e ba

se);

Cer

atia

ceae

: Mud

eron

gia

sim

plex

;ot

her

prox

imat

e: D

ingo

dini

um ?

albe

rtii

, Cas

sicu

las-

phae

ridi

a m

agna

;A

erol

iger

acea

e: C

ircu

lodi

nium

dis

tinc

tum

;ch

orat

e: O

ligos

phae

ridi

um c

ompl

ex (a

bove

the

mid

dle)

, O

. ?as

teri

gium

Ber

rias

ian

Prox

imat

e G

onya

ulac

oide

ae: T

ubot

uber

ella

rho

mbi

-fo

rmis

, Mic

rodi

nium

opa

cum

, Sir

mio

dini

um g

ross

ii;

Pare

odin

ioid

eae:

Par

eodi

nia

cera

toph

ora,

Par

agon

-ya

ulac

ysta

?bo

real

is;

Aer

olig

erac

eae:

Cyc

lone

phel

ium

cuc

ullif

orm

e

Pare

odin

ioid

eae:

Par

eodi

nia

cera

toph

ora,

Bat

iola

dini

-um

var

igra

nosu

m;

Aer

olig

erac

eae:

Sen

onia

spha

era

jura

ssic

a;ch

orat

e: A

chom

osph

aera

nep

tuni

i

Prox

imat

e G

onya

ulac

oide

ae: S

irm

iodi

nium

gro

ssii

, T

ubot

uber

ella

apa

tela

;ot

her

prox

imat

e: D

ingo

dini

um ?

albe

rtii

, D. ?

spin

osum

, C

assi

cula

spha

erid

ia m

agna

;ch

orat

e: A

chom

osph

aera

nep

tuni

i

598


PESTCHEVITSKAYA

Tab

le 2

. (C

ontd

.)

Stag

e,su

bsta

ge

Tax

a in

com

mon

with

din

ocys

ts f

rom

Nor

th S

iber

ian

sect

ions

Eng

land

(D

uxbu

ry, 1

977,

198

0; H

ardi

ng, 1

986;

Dav

ey, 2

001)

Nor

th S

ea (

Dux

bury

et a

l., 1

999;

Dux

bury

, 201

)N

orth

wes

tern

Eur

ope

(Dav

ey, 1

979,

198

2)

Low

er

Bar

rem

ian

Uns

tudi

edPr

oxim

ate

Gon

yaul

acoi

deae

: Nel

chin

opsi

s ko

stro

mie

n-si

s (l

ower

par

t)U

nstu

died

Upp

er

Hau

teri

-vi

an

Prox

imat

e G

onya

ulac

oide

ae: C

ribr

oper

idin

ium

con

fos-

sum

, C. ?

edva

rdsi

i, N

elch

inop

sis

kost

rom

iens

is, S

tan-

ford

ella

?cr

etac

ea;

Pare

odin

ioid

eae:

Bat

iola

dini

um lo

ngic

ornu

tum

, Apr

o-bo

locy

sta

eile

ma,

A. n

eist

a;C

erat

iace

ae: M

uder

ongi

a si

mpl

ex, M

. sta

urot

a, M

. cru

-ci

s, M

. tet

raca

ntha

, Ves

pero

psis

frag

ilis

, Pse

udoc

era-

tium

pel

life

rum

;ot

her

prox

imat

e: W

allo

dini

um lu

na, W

. kru

tzsc

hii,

Gar

-do

dini

um tr

abec

ulos

um;

chor

ate:

Oli

gosp

haer

idiu

m c

ompl

ex, H

ystr

icho

dini

um

voig

tii,

H. p

ulch

rum

Prox

imat

e G

onya

ulac

oide

ae: C

ribr

oper

idin

ium

con

fos-

sum

, Nel

chin

opsi

s ko

stro

mie

nsis

;Pa

reod

inio

idea

e: B

atio

ladi

nium

long

icor

nutu

m, A

pro-

bolo

cyst

a ei

lem

a, A

. nei

sta;

othe

r pr

oxim

ate:

Cas

sicu

lasp

haer

idia

mag

na, G

ardo

-di

nium

trab

ecul

osum

; cho

rate

: Hys

tric

hodi

nium

voi

gtii

, O

ligo

spha

erid

ium

com

plex

Prox

imat

e G

onya

ulac

oide

ae: N

elch

inop

sis

kost

rom

ien-

sis,

Cri

brop

erid

iniu

m ?

edva

rdsi

i;Pa

reod

inio

idea

e: A

prob

locy

sta

neis

ta;

Cer

atia

ceae

: Mud

eron

gia

sim

plex

, M. c

ruci

s, M

. ext

ensi

-va

, Pse

udoc

erat

ium

pel

life

rum

;ot

her

prox

imat

e: C

assi

cula

spha

erid

ia m

agna

, C. r

etic

u-la

ta;

chor

ate:

Hys

tric

hodi

nium

pul

chru

m (

abun

dant

), H

. voi

g-ti

i (so

met

imes

sig

nifi

cant

), S

pini

feri

tes

ram

osus

, Oli

go-

spha

erid

ium

com

plex

(so

met

imes

abu

ndan

t)

Low

er

Hau

teri

-vi

an

Pare

odin

ioid

eae:

Bat

iola

dini

um v

arig

rano

sum

, B. l

on-

gico

rnut

um;

Cer

atia

ceae

: Mud

eron

gia

sim

plex

, M. s

taur

ota,

Pse

udo-

cera

tium

pel

life

rum

;ot

her

prox

imat

e: W

allo

dini

um lu

na, W

. kru

tzsc

hii,

Gar

-do

dini

um tr

abec

ulos

um;

chor

ate:

Oli

gosp

haer

idiu

m c

ompl

ex, H

ystr

icho

dini

um

voig

tii,

H. p

ulch

rum

Prox

imat

e G

onya

ulac

oide

ae: N

elch

inop

sis

kost

rom

iens

is;

Cer

atia

ceae

: Mud

eron

gia

tetr

acan

tha;

othe

r pr

oxim

ate:

Cas

sicu

lasp

haer

idia

mag

na, G

ardo

d-in

ium

trab

ecul

osum

;ch

orat

e: O

ligo

spha

erid

ium

com

plex

Pare

odin

ioid

eae:

Bat

iola

dini

um v

arig

rano

sum

, B. l

ongi

-co

rnut

um;

Cer

atia

ceae

: Mud

eron

gia

sim

plex

, M. c

ruci

s;ot

her

prox

imat

e: C

assi

cula

spha

erid

ia m

agna

, C. r

etic

u-la

ta, G

ardo

dini

um tr

abec

ulos

um;

chor

ate:

Hys

tric

hodi

nium

pul

chru

m (

abun

dant

), H

. voi

g-ti

i (so

met

imes

sig

nifi

cant

), O

ligo

spha

erid

ium

com

plex

(s

omet

imes

abu

ndan

t)

Low

erV

alan

-gi

nian

Prox

imat

e G

onya

ulac

oide

ae: T

rich

odin

ium

cil

iatu

m,

Hes

lert

onia

hes

lert

onen

sis,

Tub

otub

erel

la a

pate

la;

Pare

odin

ioid

eae:

Bat

iola

dini

um v

arig

rano

sum

;C

erat

iace

ae: M

uder

ongi

a si

mpl

ex, M

. cru

cis;

othe

r pr

oxim

ate:

Wal

lodi

nium

luna

, W. k

rutz

schi

i, D

in-

godi

nium

?al

bert

ii;

aero

liger

acea

e: C

ircu

lodi

nium

dis

tinc

tum

Prox

imat

e G

onya

ulac

oide

ae: N

elch

inop

sis

kost

rom

ien-

sis,

Hes

lert

onia

hes

lert

onen

sis,

Tub

otub

erel

la a

pate

la;

othe

r pr

oxim

ate:

Cas

sicu

lasp

haer

idia

mag

na;

chor

ate:

Olig

osph

aeri

dium

com

plex

(fr

om th

e m

iddl

e of

Par

atol

lia)

Prox

imat

e G

onya

ulac

oide

ae: W

revi

ttia

hel

icoi

dea,

Sir

-m

iodi

nium

gro

ssii

, Tri

chod

iniu

m c

ilia

tum

, Tub

otub

erel

la

apat

ela,

Hes

lert

onia

hes

lert

onen

sis;

Cer

atia

ceae

: Mud

eron

gia

sim

plex

, M. c

ruci

s;ot

her

prox

imat

e: C

assi

cula

spha

erid

ia m

agna

, C. r

etic

u-la

ta, D

ingo

dini

um ?

albe

rtii

, Fro

mea

am

phor

a;ch

orat

e: O

ligo

spha

erid

ium

dil

ucul

um

Ber

rias

ian

Prox

imat

e G

onya

ulac

oide

ae: T

ubot

uber

ella

apa

tela

;ot

her

prox

imat

e: W

allo

dini

um k

rutz

schi

i, D

ingo

dini

um

?alb

erti

i, D

. ?sp

inos

um;

chor

ate:

Ach

omos

phae

ra n

eptu

nii

Prox

imat

e: D

ingo

dini

um ?

spin

osum

, Cas

sicu

lasp

hae-

ridi

a m

agna

;ch

orat

e: A

chom

osph

aera

nep

tuni

i

Prox

imat

e G

onya

ulac

oide

ae: S

irm

iodi

nium

gro

ssii

, T

ubot

uber

ella

apa

tela

, Ald

orfi

a di

ctyo

ta;

Pare

odin

ioid

eae:

Bat

iola

dini

um v

arig

rano

sum

;ot

her

prox

imat

e: D

ingo

dini

um m

inut

um, D

. ?al

bert

ii,

D. ?

spin

osum

, Cas

sicu

lasp

haer

idia

mag

na



Tab

le 2

. (C

ontd

.)

Stag

e,su

bsta

ge

Tax

a in

com

mon

with

din

ocys

ts f

rom

Nor

th S

iber

ian

sect

ions

Nor

ther

n G

erm

any

(Prö

ssl,

1990

)N

orw

ay (

Aar

hus

et a

l., 1

986)

Low

er

Bar

rem

ian

Pare

odin

ioid

eae:

Apr

obol

ocys

ta e

ilem

a ;ot

her

prox

imat

e: W

allo

dini

um k

rutz

schi

iU

nstu

died

Upp

er

Hau

teri

-vi

an

Prox

imat

e G

onya

ulac

oide

ae: C

ribr

oper

eidi

nium

con

foss

um, C

. ?ed

vard

sii,

Stan

for-

dell

a ?c

reta

cea,

S. e

xang

uia,

Wre

vitt

ia ?

diut

ina,

End

oscr

iniu

m c

ampa

nula

, Nel

chi-

nops

is k

ostr

omie

nsis

;Pa

reod

inio

idea

e: B

atio

ladi

nium

long

icor

nutu

m, B

. jae

geri

, Apr

obol

ocys

ta n

eist

a,

A. e

ilem

a;C

erat

iace

ae: P

seud

ocer

atiu

m p

elli

feru

m, M

uder

ongi

a au

stra

lis,

M. s

impl

ex, M

. tet

ra-

cant

ha, M

. sta

urot

a, O

dont

ochi

tina

ope

rcul

ata;

othe

r pr

oxim

ate:

Chl

amyd

opho

rell

a ny

ei, W

allo

dini

um k

rutz

schi

i, W

. lun

a, C

assi

cu-

lasp

haer

idia

mag

na, C

. ret

icul

ata,

Din

godi

nium

cer

vicu

lum

, Gar

dodi

nium

trab

ecu-

losu

m, G

. ord

inal

e;A

erol

iger

acea

e: C

yclo

neph

eliu

m b

revi

spin

atum

, Cir

culo

dini

um d

isti

nctu

m;

chor

ate:

Hys

tric

hodi

nium

pul

chru

m, H

. voi

gtii

, O. c

ompl

ex, D

apsi

lidi

nium

“m

ulti

s-pi

nosu

m”

Prox

imat

e G

onya

ulac

oide

ae: C

ribr

oper

eidi

nuum

con

foss

um, C

. ?ed

vard

sii;

Pare

odin

ioid

eae:

Bat

iola

dini

um v

arig

rano

sum

;C

erat

iace

ae: A

ptea

ana

phri

ssa

(per

sist

ent)

, Mud

eron

gia

sim

plex

, M. c

ruci

s, M

. sta

u-ro

ta, P

seud

ocer

atiu

m p

elli

feru

m;

othe

r pr

oxim

ate:

Cas

sicu

lasp

haer

idia

mag

na, C

. ret

icul

ata,

Chl

amyd

opho

rell

a ny

ei,

Gar

dodi

nium

trab

ecul

osum

, Wal

lodi

nium

kru

tzsc

hii;

Aer

olig

erac

eae:

Cir

culo

dini

um d

isti

nctu

m;

chor

ate:

Cau

ca p

arva

, Dap

sili

dini

um m

ulti

spin

osum

, Hys

tric

hodi

nium

pul

chru

m,

H. v

oigt

ii, O

ligo

spha

erid

ium

com

plex

, Spi

nife

rite

s ra

mos

us

Low

er

Hau

teri

-vi

an

Prox

imat

e G

onya

ulac

oide

ae: C

ribr

oper

eidi

nium

con

foss

um, C

. ?ed

vard

sii,

C. ?

mud

-er

onge

nse,

Nel

chin

opsi

s ko

stro

mie

nsis

;Pa

reod

inio

idea

e: B

atio

ladi

nium

long

icor

nutu

m;

Cer

atia

ceae

: Pse

udoc

erat

ium

pel

life

rum

, Mud

eron

gia

aust

rali

s, M

. sim

plex

, M. t

etra

-ca

ntha

, M. s

taur

ota;

othe

r pr

oxim

ate:

Chl

amyd

opho

rell

a ny

ei, W

allo

dini

um k

rutz

schi

i, W

. lun

a, C

assi

cu-

lasp

haer

idia

mag

na, C

. ret

icul

ata,

Din

godi

nium

cer

vicu

lum

, Gar

dodi

nium

trab

ecu-

losu

m;

Aer

olig

erac

eae:

Cyc

lone

phel

ium

bre

visp

inat

um, C

ircu

lodi

nium

dis

tinc

tum

;ch

orat

e: H

ystr

icho

dini

um p

ulch

rum

, H. v

oigt

ii, O

ligo

spha

erid

ium

com

plex

, Dap

sili-

dini

um “

mul

tispi

nosu

m”

Pare

odin

ioid

eae:

Bat

iola

dini

um v

arig

rano

sum

;C

erat

iace

ae: M

uder

ongi

a si

mpl

ex, M

. cru

cis,

M. s

taur

ota;

othe

r pr

oxim

ate:

Cas

sicu

lasp

haer

idia

mag

na, C

. ret

icul

ata,

Chl

amyd

opho

rell

a ny

ei,

Gar

dodi

nium

trab

ecul

osum

, Wal

lodi

nium

kru

tzsc

hii;

Aer

olig

erac

eae:

Cir

culo

dini

um d

isti

nctu

m;

chor

ate:

Hys

tric

hodi

nium

pul

chru

m, H

. voi

gtii

, Oli

gosp

haer

idiu

m c

ompl

ex

Low

erV

alan

-gi

nian

Uns

tudi

edPr

oxim

ate

Gon

yaul

acoi

deae

: Apt

eodi

nium

gra

nula

tum

, A. s

pong

iosu

m, N

elch

inop

sis

kost

rom

iens

is, W

revi

ttia

hel

icoi

dea,

Sir

mio

dini

um g

ross

ii, C

ribr

oper

idin

ium

?m

ud-

eron

gens

e;Pa

reod

inio

idea

e: B

atio

ladi

nium

var

igra

nosu

m, P

arag

onya

ulac

ysta

?bo

real

is (a

t the

ver

y ba

se);

Cer

atia

ceae

: Mud

eron

gia

sim

plex

;ot

her

prox

imat

e: C

assi

cula

spha

erid

ia m

agna

, C. r

etic

ulat

a, C

hlam

ydop

hore

lla

nyei

, F

rom

ea a

mph

ora,

Wal

lodi

nium

kru

tzsc

hii,

Gar

dodi

nium

trab

ecul

osum

;A

erol

iger

acea

e: C

ircu

lodi

nium

com

pta;

chor

ate:

Oli

gosp

haer

idiu

m d

iluc

ulum

, O. c

ompl

ex (

~fro

m th

e m

iddl

e)

Ber

rias

ian

Uns

tudi

edPr

oxim

ate

Gon

yaul

acoi

deae

: Sir

mio

dini

um g

ross

ii;

Pare

odin

ioid

eae:

Par

agon

yaul

acys

ta ?

bore

alis

;ot

her

prox

imat

e: C

assi

cula

spha

erid

ia m

agna

, Chl

amyd

opho

rell

a ny

ei, D

ingo

dini

um

?spi

nosu

m, F

rom

ea a

mph

ora,

Wal

lodi

nium

kru

tzsc

hii;

chor

ate:

Spi

nife

rite

s ra

mos

us

600


PESTCHEVITSKAYA

Tab

le 2

. (C

ontd

.)

Stag

e,su

bsta

ge

Tax

a in

com

mon

with

din

ocys

ts f

rom

Nor

th S

iber

ian

sect

ions

Bar

ents

Sea

she

lf(A

arhu

s et

al.,

199

0; S

mel

ror

et a

l. 19

98)

Mos

cow

bas

in (

Iosi

fova

, 199

6)

Subp

olar

Ura

ls a

nd S

iber

ia (

Il'in

a, 1

988;

Fed

orov

a et

al.,

199

3;

Shul

gina

et a

l., 1

994;

Leb

edev

a an

d N

ikite

nko,

199

8; K

iric

hkov

a et

al.,

199

9; R

idin

g et

al.,

199

9; B

eize

l' et

al.,

200

2)

Low

er

Bar

rem

ian

Pare

odin

ioid

eae:

Bat

iola

dini

um ?

exig

uum

, N

elch

inop

sis

kost

rom

iens

is (u

p to

the

mid

dle)

Uns

tudi

edU

nstu

died

Upp

er

Hau

teri

-vi

an

Prox

imat

e G

onya

ulac

oide

ae: E

ndos

crin

ium

ca

mpa

nula

, Sta

nfor

dell

a ?c

reta

cea,

Cri

brop

-er

eidi

nium

?ed

vard

sii;

Pare

odin

ioid

eae:

Bat

iola

dini

um ja

eger

i, B

. lon

gico

rnut

um;

Cer

atia

ceae

: Pse

udoc

erat

ium

pel

life

rum

, Mu-

dero

ngia

sim

plex

, M. a

ustr

alis

, M. s

taur

ota,

M

. tet

raca

ntha

, M. a

sym

met

rica

;ot

her p

roxi

mat

e: G

ardo

dini

um tr

abec

ulos

um,

Chl

amyd

opho

rell

a ny

ei;

Aer

olig

erac

eae:

Cir

culo

dini

um d

isti

nctu

m,

Apt

ea a

naph

riss

a;ch

orat

e: O

ligo

spha

erid

ium

com

plex

, Dap

sili

-di

nium

“m

ulti

spin

osum

,” C

ymoz

osph

aeri

di-

um “

phoe

nix”

Prox

imat

e G

onya

ulac

oide

ae: A

pteo

dini

um m

acul

atum

, E

. cam

panu

la, C

hytr

oeis

phae

ridi

a ch

ytro

ides

;Pa

reod

inio

idea

e: B

atio

ladi

nium

jaeg

eri,

B. v

arig

rano

-su

m, A

prob

oloc

ysta

nei

sta,

A. e

ilem

a;C

erat

iace

ae: P

seud

ocer

atiu

m p

elli

feru

m, M

. sim

plex

;ot

her

prox

imat

e: W

allo

dini

um lu

na, W

. kru

tzsc

hii,

W. c

ylin

dric

um, C

hlam

ydop

hore

ll n

yei,

G. t

rabe

culo

sum

, C

assi

cula

spha

erid

ia r

etic

ulat

a;A

erol

iger

acea

e: C

ircu

lodi

nium

dis

tinc

tum

;ch

orat

e: O

ligo

spha

erid

ium

com

plex

, Hys

tric

hodi

nium

pu

lchr

um, H

. voi

gtii

Uns

tudi

ed

Low

er

Hau

teri

-vi

an

Pare

odin

ioid

eae:

Bat

iola

dini

um ja

eger

i, B

. lon

gico

rnut

um;

Cer

atia

ceae

: Apt

ea a

naph

riss

a (f

rom

the

up-

per

part

), M

uder

ongi

a si

mpl

ex, M

. aus

tral

is,

M. s

taur

ota,

M. t

etra

cant

ha;

othe

r pro

xim

ate:

Gar

dodi

nium

trab

ecul

osum

, C

hlam

ydop

hore

lla

nyei

;A

erol

iger

acea

e: C

ircu

lodi

nium

dis

tinc

tum

;ch

orat

e: O

ligo

spha

erid

ium

com

plex

, Cym

o-so

spha

erid

ium

“ph

oeni

x”

Prox

imat

e G

onya

ulac

oide

ae: A

pteo

dini

um m

acul

atum

, N

. kos

trom

iens

is, A

mbo

nosp

haer

a ?s

taff

iens

is;

Pare

odin

ioid

eae:

Bat

iola

dini

um v

arig

rano

sum

;C

erat

iace

ae: M

uder

ongi

a si

mpl

ex;

othe

r pr

oxim

ate:

Wal

lodi

nium

luna

, W. k

rutz

schi

i,W

. cyl

indr

icum

, Chl

amyd

opho

rell

nye

i, G

. tra

becu

losu

m,

Cas

sicu

lasp

haer

idia

ret

icul

ata;

Aer

olig

erac

eae:

Cir

culo

dini

um d

isti

nctu

m;

chor

ate:

Oli

gosp

haer

idiu

m c

ompl

ex, H

ystr

icho

dini

um

pulc

hrum

, H. v

oigt

ii

Prox

imat

e G

onya

ulac

oide

ae: A

pteo

dini

um m

acul

atum

, Nel

chin

op-

sis

kost

rom

iens

is;

Pare

odin

ioid

eae:

B. v

arig

rano

sum

, B. l

ongi

corn

utum

;C

erat

iace

ae: M

uder

ongi

a si

mpl

ex, M

. cru

cis,

M. t

etra

cant

ha;

othe

r pr

oxim

ate:

Chl

amyd

opho

rell

a ny

ei, D

ingo

dini

um c

ervi

cu-

lum

, Wal

lodi

nium

luna

, W. k

rutz

schi

i, C

assi

cula

spha

erid

ia r

eti-

cula

ta, G

ardo

dini

um tr

abec

ulos

um;

Aer

olig

erac

eae:

Cir

culo

dini

um d

isti

nctu

m, T

enua

am

eric

ana;

chor

ate:

O. c

ompl

ex, H

ystr

icho

dini

um s

olar

e

Low

erV

alan

-gi

nian

Prox

imat

e G

onya

ulac

oide

ae: W

revi

ttia

hel

i-co

idea

Prox

imat

e G

onya

ulac

oide

ae: A

pteo

dini

um m

acul

atum

, T

rich

odin

ium

cil

iatu

m, T

. spe

eton

ense

, Sta

nfor

dell

a fa

s-ti

giat

a, T

ubot

uber

ella

apa

tela

, Sir

mio

dini

um g

ross

ii;

Pare

odin

ioid

eae:

Par

eodi

nia

cera

toph

ora;

Cer

atia

ceae

: Mud

eron

gia

sim

plex

;ot

her p

roxi

mat

e: W

allo

dini

um lu

na, W

. kru

tzsc

hii,

D. ?

al-

bert

ii, C

hlam

ydop

hore

lla

nyei

, Gar

dodi

nium

trab

ecul

o-su

m, C

assi

cula

spha

erid

ia r

etic

ulat

a, F

rom

ea a

mph

ora

Prox

imat

e G

onya

ulac

oide

ae: T

ubot

uber

ella

rho

mbi

form

is (

in th

e lo

wer

par

t), S

. orb

is, A

pteo

dini

um g

ranu

latu

m, N

elch

inop

sis

kos-

trom

iens

is, C

ribr

oper

idin

ium

?m

uder

onge

nse;

Pare

odin

ioid

eae:

Par

agon

yaul

acys

ta ?

bore

alis

(at

the

very

bas

e);

othe

r pr

oxim

ate:

Chl

amyd

opho

rell

a ny

ei, D

ingo

dini

um c

ervi

cu-

lum

, D. ?

albe

rtii

, Wal

lodi

nium

kru

tzsc

hii,

Cas

sicu

lasp

haer

idia

re-

ticu

lata

, C. m

agna

;ch

orat

e: O

ligo

spha

erid

ium

dil

ucul

um

Ber

rias

ian

Pare

odin

ioid

eae:

Par

agon

yaul

acys

ta ?

bore

a-li

sPr

oxim

ate

Gon

yaul

acoi

deae

: Apt

eodi

nium

mac

ulat

um,

Tub

otub

erel

la a

pate

la, S

irm

iodi

nium

gro

ssii

;Pa

reod

inio

idea

e: P

areo

dini

a ce

rato

phor

a;ot

her

prox

imat

e: W

. lun

a, W

. kru

tzsc

hii,

W. c

ylin

dric

um,

D. ?

albe

rtii

, C. n

yei,

C. r

etic

ulat

a, F

. am

phor

a;A

erol

iger

acea

e: S

enon

iasp

haer

a ju

rass

ica;

chor

ate:

A. n

eptu

nii,

Spin

ifer

ites

ram

osus

Prox

imat

e G

onya

ulac

oide

ae: S

tanf

orde

lla e

xang

uia,

S. o

rbis

, T

. rho

mbi

form

is, T

. apa

tela

, S. g

ross

ii, M

icro

dini

um o

pacu

m;

Pare

odin

ioid

eae:

Par

agon

yaul

acys

ta ?

bore

alis

, Im

bato

dini

um

kond

ratj

evii

;ot

her

prox

imat

e: W

allo

dini

um k

rutz

schi

i, C

. nye

i, D

ingo

dini

um

?alb

erti

i, C

assi

cula

spha

erid

ia r

etic

ulat

a, C

. mag

na;

Aer

olig

erac

eae:

Cyc

lone

phel

ium

cuc

ullif

orm

e

Not

e:N

ames

of

spec

ies

in c

omm

on w

ith N

orth

Sib

eria

n ta

xa a

re g

iven

in b

old

or u

nder

lined

, whe

n th

ey h

ave

first

or

last

occ

urre

nce

in th

e de

sign

ated

inte

rval

.



Tab

le 3

. Fir

st a

nd la

st o

ccur

renc

e of

the

Low

er C

reta

ceou

s di

nocy

st s

peci

es e

stab

lishe

d in

dif

fere

nt n

orth

ern

regi

ons

of E

uras

ia a

nd A

mer

ica

Age Barremian Hauterivian Valanginian Berriasian

Epoch earlylate middle

Paly

nolo

gica

l eve

nts

Rec

ogni

zabl

e in

dif

fere

nt r

egio

ns o

f N

orth

Eur

asia

Cas

sicu

lasp

haer

idia

mag

na (

G, N

E)

acm

e of

Apt

ea a

naph

riss

a (e

very

whe

re e

xcep

t for

Rus

sia)

;

acm

e of

Apt

ea a

naph

riss

a (e

very

whe

re e

xcep

t for

Rus

sia)

;N

elch

inop

sis

kost

rom

iens

is (

G, N

E, B

S)

Pro

toel

lipso

dini

um c

lavu

lum

(N

E, B

S, M

B)

Cri

brop

erid

iniu

m c

onfo

ssum

, Kio

kans

ium

pol

ypes

, Tan

yosp

haer

idiu

m b

olet

us: (

G, N

E);

Cri

brop

erid

iniu

m o

rtho

cera

s (S

C, B

S, G

);E

llips

oidi

ctyu

m im

perf

ectu

m (

SR);

Sp

inife

rite

s pr

imae

vus

(G, N

E)

Olig

osph

aeri

dium

com

plex

(ev

eryw

here

exc

ept f

or M

B)

Cau

aca

parv

a (S

R, S

);P

arag

onya

ulac

ysta

cap

illos

a (N

E, A

C, S

C);

Bat

iola

dini

um ?

goch

tii (

SC, A

C, M

B);

Egm

onto

dini

um to

ryna

(G

, NE

, SR

);

Cas

sicu

lasp

haer

idia

ret

icul

ata

(MB

, S)

Olig

osph

aeri

dium

dilu

culu

m (

NE

, SR

, MB

)

Bat

iola

dini

um p

ellif

erum

(SR

, NE

, MB

); K

leith

rias

phae

ridi

um “

sim

plic

ispi

num

” (S

R, M

B);

O

ccis

ucys

ta te

ntor

ium

(N

E, S

R, G

, S);

Pho

bero

cyst

a ne

ocom

ica

(SR

, MB

);C

ircu

lodi

nium

dis

tinct

um, E

ndos

crin

ium

cam

panu

la: (

SC, G

)

Rec

ogni

zabl

e in

Can

ada

only

Fro

mea

triq

uetr

a, P

seud

ocer

atiu

m r

etus

um: (

AC

)

End

ocer

atiu

m d

ettm

anae

(A

C);

late early earlylate earlylate

Gon

yaul

acys

ta ju

rass

ica

(BS,

G)

Elli

psoi

dict

yum

sag

ena

(G, B

S, M

B)

Gon

yaul

acys

ta e

isen

acki

i (B

S, M

B)

Lith

odin

ia p

ertu

sa (

G, N

E, M

B);

Spi

nife

rite

s al

atus

(G

, MB

); N

elch

inop

sis

kost

rom

iens

is (

SC, S

);

Din

godi

nium

?sp

inos

um (

NE

, SR

, S)

Pse

udoc

erat

ium

“re

gium

” (S

C)

Kal

losp

haer

idiu

m ?

circ

ular

e, P

ilosi

dini

um f

iliat

um,

Val

vaeo

dini

um a

tlant

icum

: (A

C);

C

teni

dodi

nium

?sc

issu

m, L

ante

rna

spor

tula

Cir

culo

dini

um a

ttada

licum

, Sub

tilis

phae

raA

pteo

dini

um a

piat

um, B

atia

casp

haer

a ag

glut

inat

a,

Bio

rbife

ra jo

hnei

ngii,

Cir

culo

dini

um h

irte

llum

: (SC

)

Elli

psoi

dict

ium

cin

ctum

, Scr

inio

dini

um c

ryst

allin

um: (

AC

);

Imba

todi

nium

kon

drat

jevi

i (û

ä)

Hys

tric

hosp

haer

idiu

m r

ecur

vatu

m (

SC)

Tric

hodi

nium

eri

nace

oide

s (A

C)

Lith

osph

aeri

dium

sip

honi

phor

um (

SC)

Apt

eodi

nium

api

atum

, Bat

iaca

spha

era

aggl

utin

ata,

Cal

igod

iniu

m a

cera

s,

Cte

nido

dini

um ?

scis

sum

, Fro

mea

sen

ilis,

Goc

hteo

dini

a ju

dile

ntin

ae,

Mud

eron

gia

“tom

aszo

wen

sis,

” O

dont

ochi

tina

oper

cula

ta,

Bat

iola

dini

um ?

exig

uum

, Bat

iola

dini

um ja

eger

i,

Syst

emat

opho

ra o

rbife

ra (

SC);

Am

phor

ula

met

aelli

ptic

a,

Can

tulo

dini

um a

rthu

riae

, Se

ntus

idin

ium

aff

. rio

ultii

: (SC

)

Cir

culo

dini

um h

irte

llum

, Cri

brop

erid

iniu

m s

epim

entu

m, C

teni

dodi

nium

ele

gant

um, B

iorb

ifera

john

ewin

gii,

Rhy

ncho

dini

opsi

s se

rrat

a, S

yste

mat

opho

ra c

ompl

icat

a: (

SC)

Not

es.

– f

irst

occ

urre

nce,

–

last

occ

urre

nce(

SC)

sout

hern

and

sou

thea

ster

n C

anad

a, (

AC

) A

rctic

Can

ada,

(G

) G

reen

land

, Wes

t Eur

ope,

(N

E)

Sout

h E

ngla

nd a

nd n

orth

ern

regi

ons

regi

ons

of G

erm

any,

Fra

nce

and

Den

mar

k, (

SR)

subp

olar

reg

ions

, (B

S) B

aren

ts S

ea s

helf

, (M

B)

Mos

cow

bas

in, (

S) S

iber

ia; p

rint

ed in

bol

d ar

e sp

ecie

s fo

und

in th

e st

udie

d se

ctio

nsof

Nor

th S

iber

ia.

Bat

iola

dini

um v

arig

rano

sum

, Sub

tilis

phae

ra p

erlu

cida

: (SC

)

Lept

odin

ium

mam

illife

rum

,M

oesi

odin

ium

rai

lean

ui: (

AC

);

Cri

brop

erid

iniu

m s

aetig

erum

, Cri

brop

erid

iniu

m s

pino

retic

ulat

um,

Kal

losp

haer

idiu

m ?

circ

ular

e, L

epto

dini

um e

piso

mum

,

Olig

osph

aeri

dium

alb

erte

nse:

(A

C)

Rhy

ncho

dini

opsi

s se

rrat

a: (

SC);

?pir

naen

sis,

Sur

culo

spha

erid

ium

?l

ongi

furc

atum

: (SC

);C

ylon

ephe

lium

van

noph

orum

(SC

, AC

)

Lept

odin

ium

epi

som

um, P

rolix

osph

aeri

dium

“sp

issu

m,”

Tub

otub

erel

la r

hom

bifo

rmis

: (A

C);

602


PESTCHEVITSKAYA


Epoch earlylate middlelate early earlylate earlylateT

ab

le 3

. (C

ontd

.)

Paly

nolo

gica

l eve

nts

Rec

ogni

zabl

e on

ly in

nor

thw

este

rn E

urop

e an

d B

aren

ts S

ea s

helf

Fro

mea

qua

drug

ata

(NE

, BS)

; Car

podi

nium

gra

nula

tum

(N

E)

Can

ning

iops

is “

tabu

lata

,” C

ribr

oper

idin

ium

bor

eas,

Im

pagi

dini

um d

iver

sum

: (N

E);

K

leith

rias

phae

ridi

um ?

sarm

entu

m (

NE

, SR

); M

uder

ongi

a im

pari

lis, E

llips

odin

ium

ret

icul

atum

: (N

E)

Nyc

teri

cyst

a ?p

anno

sa, O

ligos

phae

ridi

um fe

nest

ratu

m: (

NE

) A

chom

osph

aera

ram

ulife

ra, G

onya

ulac

ysta

com

pta,

Im

pagi

dini

um a

lect

opho

rum

,

Cri

brop

erid

iniu

m “

com

ptum

” (B

S)B

atia

casp

haer

a m

ica,

Gon

yaul

acys

ta d

ualis

(B

S)A

pteo

dini

um r

etic

ulat

um, S

epis

pinu

la a

ncor

ifera

: (è

Ö);

Mud

eron

gia

pari

ata

(BS)

;C

erbi

a ta

bula

ta, E

xigu

isph

aera

ple

ctili

s, H

ystr

icho

dini

um c

ompa

ctum

,P

tero

dini

um p

rem

nos,

Rhy

ncho

dini

opsi

s fim

bria

ta: (

NE

)

Flo

rent

inia

man

telli

i (N

E)

Subt

ilisp

haer

a te

rrul

a (N

E)

Ves

pero

psis

fra

gilis

, Cor

onife

ra o

cean

ica,

Dow

nies

phae

ridi

um a

cicu

lare

, Flo

rent

inia

inte

rrup

ta,

Fro

mea

com

plic

ata,

Sub

tilis

phae

ra te

rrul

a, T

alei

spha

era

hydr

a, W

revi

ttia

cass

idat

a: (

NE

);

Cri

brop

erid

iniu

m “

alve

olat

um,”

Cri

brop

erid

iniu

m ?

conu

tum

, Nex

osis

pinu

m v

etus

culu

m, A

prob

o-

Can

ning

iops

is c

olliv

eri,

Cir

culo

dini

um b

revi

spin

osum

, Com

etod

iniu

m ?

com

atum

, Cri

brop

erid

iniu

m “

diap

hanu

m,”

Dap

silid

iniu

mla

min

aspi

nosu

m, D

owni

esph

aeri

dium

mul

tispi

nosu

m, G

ardo

dini

um o

rdin

ale,

Hys

tric

hodi

nium

furc

atum

, Hys

tric

hodi

nium

ram

oide

s,R

hync

hodi

niop

sis

aptia

na, S

pini

feri

tes

spee

tone

nsis

, Sta

nfor

della

ord

ocav

ata,

Tan

yosp

haer

idiu

m s

alpi

nx, S

ubtil

isph

aera

per

luci

da,

Wre

vitti

a ?p

erfo

robt

usa:

(N

E);

Dap

silid

iniu

m m

ultis

pino

sum

(NE

, SR

); M

uder

ongi

a ae

quic

ora,

Mud

eron

gia

asym

met

rica

, P

seud

ocer

atiu

m n

udum

, Pal

aeop

erid

iniu

m c

reta

ceum

, Cym

osos

phae

ridi

um ?

phoe

nix

(SR

)

Cri

brop

erid

iniu

m ?

tenu

icer

as, M

uder

ongi

a st

auro

ta: (

SR);

H

ystr

icho

spha

erid

ium

arb

oris

pinu

m, M

uder

ongi

a ex

tens

iva:

(N

E)

Dis

cors

ia n

anna

, Exo

chos

phae

ridi

um p

hrag

mite

s, N

emat

osph

aero

psis

vet

uscu

la,

Syst

emat

opho

ra s

ilybu

m (

SR)

Cym

osos

phae

ridi

um v

alid

um (

NE

)

Exi

guis

phae

ra p

hrag

ma,

Lag

enor

hytis

del

icat

ula

(NE

)

Goc

hteo

dini

a vi

llosa

sub

sp. m

ultif

urca

ta (

NE

, SR

);

Gon

yaul

acys

ta a

ngle

se, I

mpl

etos

phae

ridi

um tr

ibul

iferu

m:

(SR

)

Goc

hteo

dini

a ve

rruc

osa,

Pro

lixos

phae

ridi

um g

ranu

losu

m: (

SR);

St

iphr

osph

aeri

dium

arb

ustu

m (

NE

)

Kle

ithri

asph

aeri

dium

fasc

iatu

m, K

. eoi

node

s, D

iaca

nthu

m h

ollis

teri

, Teh

amad

iniu

m e

vitti

: (N

E);

Apr

obol

ocys

ta n

eist

a (N

E, B

S); C

ribr

oper

idin

ium

?co

rnut

um (

NÖ

)

End

oscr

iniu

m

h‡rÓ

(N

E, B

S)

Bat

iaca

spha

era

mic

a (N

E);

Spi

nife

rite

s fe

nest

ratu

s (N

E

Nex

osis

pinu

m v

etus

culu

m (

NE

, BS)

; Asc

odin

ium

fiss

ilum

, Cri

brop

erid

iniu

m c

olum

,C

ribr

oper

idin

ium

frag

ilis,

Exi

guis

phae

ra p

hrag

ma,

Lag

enor

hytis

del

icat

ula,

Pte

rodi

-

ra, T

etra

chac

ysta

spi

nosi

gibb

eros

a: (

NE

); M

endi

codi

nium

gro

enla

ndic

um,

feri

tes

alat

us, W

allo

dini

um c

ylin

dric

um, W

revi

ttia

?diu

tina:

(B

S)

Apr

obol

ocys

ta e

ilem

a (N

E; B

S)

Aus

tral

isph

aera

frag

ilis,

Can

ning

ia d

uxbu

ryi,

Can

ning

ia g

rand

is,

areo

lata

, Kle

ithri

asph

aeri

dium

por

osis

pinu

m: (

NE

)

Stip

hros

phae

ridi

um a

rbus

tum

: (N

E)

Cir

culo

dini

um c

ompt

a, O

ligos

phae

ridi

um ju

nctu

m (

NE

)

Syst

emat

opho

ra p

alm

ula,

S. s

coia

cea:

(N

E)

Apr

obol

ocys

ta e

xtre

ma,

Spi

nife

rite

s ?s

pong

iosu

s,

Cte

nido

dini

um ?

schi

zabl

ata,

Dic

hado

gony

aula

x cu

lmul

a, P

apua

dini

um a

picu

latu

m, S

tiphr

osph

aeri

dium

Rot

osph

aero

psis

thul

e (N

E)

Goc

hteo

dini

a ve

rruc

osa,

Sen

tusi

dini

um s

epar

atum

(SR

);

Kal

ypte

a di

cera

s (S

R)

Rec

ogni

zabl

e in

Gre

enla

nd o

nly

Kle

ithri

asph

aeri

dium

cor

ruga

tum

Bat

iola

dini

um p

ellif

erum

Bat

iaca

spha

era

spum

osa,

Pro

lixos

phae

ridi

um

Des

moc

ysta

ple

cta

Cri

brop

erid

iniu

m e

xilic

rist

atum

Bat

iola

dini

um p

ellif

erum

, Egm

onto

dini

um to

ryna

End

oscr

iniu

m g

ranu

latu

m

Cri

brop

erid

iniu

m ?

edva

rdsi

i, D

apsi

lidin

ium

dier

ense

, Sen

tusi

dini

um v

erru

cosu

s,W

allo

dini

um e

long

atum

Cri

brop

erid

iniu

m e

xilic

rist

atum

war

reni

i, H

esle

rton

ia h

esle

rton

ensi

s, E

gmon

to-

dini

um to

ryna

; Pse

udoc

erat

ium

pel

lifer

um

Am

phor

ula

expi

rata

(N

E, S

R);

Egm

onto

dini

um p

olyp

laco

phor

um (

NE

)

Teha

mad

iniu

m d

avey

i: (

NE

)

dict

yoph

orum

: (C

E);

Lep

todi

nium

mill

ioud

ii, L

epto

dini

um s

ubtil

e, T

rich

odin

ium

sca

rbur

ghen

se: (

BS)

nium

“?c

ingu

latu

s,”

Tany

osph

aeri

dium

mag

netic

um, R

hync

hodi

niop

sis

clad

opho

-

Mic

rodi

nium

opa

cum

, Mud

eron

gia

aequ

icor

na, R

igua

della

aem

ula,

Spi

ni-

Cym

osos

phae

ridi

um v

alid

um, D

esm

ocys

ta s

impl

ex, S

yste

mat

opho

ra

Wre

vitti

a ?d

iutin

a (N

E, S

R);

Ato

podi

nium

pol

ygon

ale,

Sys

tem

atop

hora

pal

mul

a: (

BS)

Nem

atos

phae

rops

is s

cala

, Mud

eron

gia

cruc

is, M

. tet

raca

ntha

, Pro

toel

lipso

idin

ium

spi

nosu

m: (

NE

);

locy

sta

neis

ta, a

bund

ance

of

Gar

dodi

nium

trab

ecul

osum

: (N

E);

Apt

ea a

naph

riss

a (S

R)

Apr

obol

ocys

ta e

ilem

a: (

NE

, BS)




Epoch earlylate middlelate early earlylate earlylateT

ab

le 3

. (C

ontd

.)

Paly

nolo

gica

l eve

nts

Rec

ogni

zabl

e in

the

Mos

cow

bas

in o

nly

Cyc

lone

phel

ium

hex

alob

osum

Cri

brop

erid

iniu

m c

ooks

onia

e

Gar

dodi

nium

atte

nuat

um, N

eodi

acro

dium

bre

visp

inos

um, N

. cor

nicu

latu

m,

Cri

brop

erid

iniu

m c

ooks

onia

e, K

ioka

nsiu

m p

rola

tum

,Le

ptod

iniu

m ?

hadr

um, P

seud

ocer

atiu

m iv

eri,

Subt

ilisp

haer

a ch

eit

Am

bono

spha

era

?sta

ffin

ensi

s, A

pteo

di-

dia

cera

stes

, Cyc

lone

phel

ium

mau

gaad

, Epi

tric

ysta

vin

kens

is, H

ystr

icho

gy-

ta, L

ithod

inia

dia

phan

a, M

icro

dini

um d

ensi

gran

ulat

um, S

enon

iasp

haer

a

War

reni

a ?b

revi

spin

osa

Gar

dodi

nium

low

ii, G

onya

ulac

ysta

Apt

eodi

nium

def

land

rei,

Cyc

lone

phel

ium

mau

gaad

, Gar

dodi

nium

low

ii,

diap

hana

, Mic

rodi

nium

den

sigr

anul

atum

, Pro

toel

lipso

dini

um m

ugat

ae,

Com

etod

iniu

m w

hite

i

Lith

odin

ia p

erfo

rata

, Pro

toba

tiola

dini

um r

ossi

cum

,

Apt

eodi

nium

gra

nulif

erum

, Apt

eodi

nium

ger

asim

ovii,

Cri

brop

erid

iniu

m

Mud

eron

gia

brev

ispi

nosa

, Pro

lixos

phae

ridi

um p

arvi

spin

osum

,

Teha

mad

iniu

m d

avey

i

Pro

lixos

phae

ridi

um c

onul

um,

Gon

yaul

acys

ta d

enta

ta,

Syst

emat

opho

ra o

vata

Apt

eodi

nium

mac

ulat

um, C

anni

ngia

gra

ndis

, Can

ning

ia r

etic

ulat

a, C

omet

odin

ium

whi

tei,

Rec

ogni

zabl

e in

Sib

eria

onl

y

Apr

obol

ocys

ta g

alea

ta

Ves

pero

psis

may

i, C

yclo

neph

eliu

m in

tons

um,

Dru

ggid

ium

juba

tum

, O

ligos

phae

ridi

um

Ten

ua a

mer

ican

a

Mud

eron

gia

brev

ispi

nosa

,A

mbo

nosp

haer

a de

licat

a

Din

godi

nium

tube

rosu

m,

Cri

brop

erid

iniu

m g

ranu

latu

m

Mud

eron

gia

aust

ralis

, A

prob

oloc

ysta

gal

eata

Am

bono

spha

era

delic

ata

Esc

hari

spha

erid

ia r

udis

N. t

imof

eevi

i, P

seud

ocer

atiu

m a

ulae

um

nium

def

land

rei,

Apt

eodi

nium

gra

nulif

e-ru

m, A

pteo

dini

um g

eras

imov

ii, C

hitr

oeis

phae

ri-

lon

mem

bran

iforu

m, I

mpa

gidi

nium

oro

cavi

opse

, Lith

odin

ia a

rcan

itabu

la-

jura

ssic

a, T

rich

odin

ium

dis

cus,

Tub

otub

erel

la a

pate

la,

Gar

dodi

nium

trab

ecul

osum

, Hes

lert

onia

pel

luci

da, S

tanf

orde

lla f

astig

iata

, Wal

lodi

nium

luna

volk

ovae

, Epi

tric

ysta

vin

kens

is, L

ithod

inia

per

fora

ta,

Pro

toba

tiola

dini

um r

ossi

cum

, Pro

toel

lipso

dini

um s

eghi

re,

Surc

ulos

phae

ridi

um c

ribr

otub

ilife

rum

teic

hos

Hys

tric

hogy

lon

mem

bran

iforu

m, I

mpa

gidi

nium

ord

ocav

iops

e, L

ithod

inia

P. t

ouile

, Rho

mbo

della

ves

ca, T

rich

odin

ium

dis

cus,

War

reni

a ?b

revi

spin

osa

P. e

xpol

itum

abac

ulum

Tany

osph

aeri

dium

var

ieca

lam

us,

Sepi

spin

ula

?“hu

guon

iotii

”

Stan

ford

ella

exa

ngui

a, T

rich

odin

ium

spe

eton

ense

Ach

omos

phae

ra v

erdi

eri,

Par

eodi

nia

hallo

sa

Ath

igm

atoc

ysta

gla

bra

Ach

omos

phae

rave

rdie

ri, P

areo

dini

a ha

llosa

,Le

ptod

iniu

m e

umor

phum

,

Cri

brop

erid

iniu

m g

loba

tum

Rec

ogni

zabl

e in

sub

pola

r

Apt

eodi

nium

re

ticul

atum

(G

, NE

);B

atio

ladi

nium

long

icor

nut-

Nyc

teri

cyst

a ?v

itrea

,

Tub

otub

erel

la

Cyc

lone

phel

ium

Par

agon

yaul

acys

ta

Cri

brop

erid

iniu

m

Cyc

lone

phel

ium

Pho

bero

cyst

a

Spin

ifer

ites

ram

osus

(A

C, S

)

Rec

ogni

zabl

e in

Bor

eal

Isth

moc

ystis

Apr

obol

ocys

ta n

eist

a, G

o-

“goc

htii”

(SC

, NE

)

Ach

omos

phae

ra

T. m

agne

ticum

, C

ribr

oper

idin

ium

tens

ifte

nse,

F. a

mph

ora,

F. f

ragi

lis

regi

ons

only

prov

ince

onl

y

dist

inct

a (N

E, M

B)

tum

(A

C, G

, SR

, NE

)

Pse

udoc

erat

ium

tove

ae,

unci

nata

: (A

C, G

)

cucu

llifo

rme

(AC

, S)

tabu

lata

(N

E, M

B)

cucu

llifo

rme

(AC

, S)

?bor

ealis

(A

C, G

, S)

mud

eron

gens

e, T

rich

odin

ium

cast

anea

: (A

C, N

E);

Bat

iola

di-

nium

long

icor

nutu

m (

NE

, S)

nyau

lacy

sta

teic

hos,

Hys

tri-

chog

ylon

sto

lidot

a: (

NÖ

, MB

);C

alla

iosp

haer

idiu

m a

sym

met

-ri

cum

, Pse

udoc

erat

ium

nept

unii

( SC

, NB

);

Spin

iferi

tes

dent

atus

(N

E, S

C)

604


PESTCHEVITSKAYA

Table 4. Palynological substantiation of dinocyst reference level established in North Siberia

Dinocyst levels Palynological event Regions, where palynological events are recognized

Lower boundary:Hystrichodinium solare, Mude-rongia spp. (DA5);lower Hauterivian, middle Ho-molsomites bojarkensis

First occurrence of Hystricho-dinium solare

Subpolar Urals, beginning from the lower Hauterivian (Lebedeva and Ni-kitenko; 1998)

First occurrence of Muderongia staurota

Barents Sea shelf, beginning from the upper Valanginian (Aarhus et al., 1986)Northwestern Europe, beginning from the upper Hauterivian (Duxbury, 1977; Harding, 1986; A Stratigraphic…, 1992)

First occurrence of Muderongia tetracantha

Barents Sea shelf, beginning from the Hauterivian (Aarhus et al., 1990; Smel-ror et al., 1998);Northwestern Europe, beginning from the upper Hauterivian (Duxbury, 1977; Davey, 1979; Nøhr-Hansen, 1993);crucis/tetracantha: in northwestern Europe since the upper part of the lower Valanginian (Polyptychites) (A Stratigraphic…, 1992); in the Subpolar Urals since the upper Valanginian (Lebedeva and Nikitenko; 1998)

Diversification of the genus Muderongia

Valanginian assemblages commonly include two species M. simplex + M. cruces and M. tomaszovensis or M. perforata for the lower substage (Bujak and Williams, 1978; Davey, 1979; Davies, 1983; A Stratigraphic…, 1992) and + M. extensiva or M. staurota for the upper one (Duxbury, 1977; Fisher and Riley, 1980; Aarhus et al., 1986);lower Hauterivian: 4 species M. tetracantha, M. asymmetrica, M. aequicorna, and M. australis in the Barents Sea shelf (Aarhus et al., 1990); upper Hauteriv-ian–Barremian: 2–4 species in northwestern Europe and Greenland (Duxbury, 1977, 1980, 2001; A Stratigraphic…, 1992; Nøhr-Hansen, 1993)

LB Aldorfia sibirica, Apro-bolocysta galeata, (DA4): mid-dle ramulicosta

First abundance peak of Dingo-dinium cerviculum

Persistent abundance is more typical of the upper Valanginian and Hauterivi-an: Norway (Aarhus, 1986), Subpolar Urals (Lebedeva and Nikitenko, 1998)

Lower boundary Oligosphae-ridium complex,Dingodinium cerviculum (DA3): lower Valanginian,middle Euryptychites quadrifi-dus

First occurrence of Mude-rongia cruces (borehole Ro-manovskaya)

Northern areas of West Europe (Daveey, 1979; A Stratigraphic…, 1992)

First occurrence of Oligo-sphaeridium complex

First occurrence practically isochronous in the lower part of the lower Valang-inian: Canada (Bujak and Williams, 1978; Brideaux and McIntyre, 1980; Davies, 1983), Greenland (Piasecki, 1979), northwestern Europe (Duxbury, 1977, 2001; Davey, 1979; Aarhus et al., 1986; A Stratigraphic…, 1992)

First occurrence of Dingodin-ium crviculum

In West Europe first occurrence in the upper Volgian Substage (Davey, 1979);In Arctic Canada and Siberia first occurrence in lower part of the lower Val-anginian (Brideaux and McIntyre, 1980; Davies, 1983; Lebedeva and Nikiten-ko, 1998)

Lower boundary Eschari-sphaeridia spp., Oligosphae-ridium spp., Circulodinium spp. (DA2): lower Valanginian, lower part of Neotollia kli-movskiensis

Last occurrence of Dingo-dinium ?spinosum somewhat lower (Severo-Volo-gochanskaya)

Practically isochronous last occurrence at the Berriasian top: northern areas of West Europe (Duxbury, 1977; Davey, 1979; Fisher, Riley, 1980; A strati-graphic…, 1992; Duxbury et al., 1999)

Last occurrence of Pargo-nyaulacysta ?borealis

Last occurrence in lower part of the lower Valanginian: Arctic Canada (McIn-tyre, Brideaux, 1980), Greenland (Hakansson et al., 1981), Norway (Aarhus et al., 1986), Siberia (Lebedeva and Nikitenko, 1998)

Sharply decreased diversity of Pareodinioideae

–

Loer boundary Pareodinioide-ae, Cassiculasphaeridia reticu-lata, Batioladinium varigrano-sum (DA1); upper Berriasian, Surites analogus base

First occurrence of Batiola-dinium varigranosum

First occurrence in the mid-Berriasian: Newfoundland (Van Helden, 1986), northwestern Europe (Davey, 1982); last occurrence in the mid-Barremian of the Barents Sea shelf (Smelror et al., 1998);Characteristic component of Valanginian and Hauterivian assemblages in northwestern Europe (Duxbury, 1977; A Stratigraphic…, 1992; Davey, 2001) and Moscow basin (Iosifova, 1996)

First occurrence of Cassicu-lasphaeridia reticulata

First occurrence at the base of the Bojarkia payeri Zone in the Subpolar Urals (Lebedeva and Nikitenko, 1998);Characteristic component of Valanginian, Hauterivian and Barremian assem-blages in northwestern Europe (Duxbury, 1977; Aarhus et al., 1986; A Strati-graphic…, 1992; Davey, 2001) and Moscow basin (Iosifova, 1996)

First occurrence of Tanyo-sphaeridium magneticum

The lower–middle Valanginian of Arctic Canada (Davies, 1983); the lower upper Valanginian of the Barents Sea shelf (Smelror et al., 1998);The Hauterivian–lower Barremian of northern Germany (Prössl, 1990)



Table 4. (Contd.)

Dinocyst levels Palynological event Regions, where palynological events are recognized

Canningia spp.–Nelchinopsis kostromiensis Beds (DA8): lower part of the lower Barre-mian

Presence of Nelchinopsis kos-tromiensis

The latest specimens are discovered in lower part of the lower Barremian in Greenland and northwestern Europe (Nöhr-Hansen, 1993)

Presence of Aprobolocysta eilema

The latest specimens are discovered in lower part of the lower Barremian in northwestern Europe (Duxbury, 1980, 2001; A Stratigraphic…, 1992)

Lower boundary, Aprobolocys-ta eilema–A. neista–Odonto-chitina spp. assemblage (DA7): the upper Hauterivian base

First occurrence of Aprobolo-cysta eilema

First occurrence at the base of the upper Hauterivian (Duxbury, 1977, 2001; A Stratigraphic…, 1992)

First occurrence of Aprobo-locysta neista

First occurrence in upper part of the lower Hauterivian (Duxbury, 2001)

First occurrence of Odonto-chitina operculata

First occurrence in the Valanginian of Arctic Canada (Davies, 1983) and since the upper Hauterivian in the Barents Sea shelf and northern Germany (Aarhus et al., 1990; Prössl, 1990

First occurrence of Psedo-ceratium expolitum, Gonya-ulacysta ?kleithria, Cyclo-nephelium intonsum

First occurrence of Psedoceratium expolitum in the lower Barremian of Mos-cow syneclise (Iosifova, 1986); Gonyaulacysta ?kleithria and Cyclonepheli-um intonsum unknown from the Berriasian–Barremian of North Eurasia and America are described from the Aptian–Albian of South England (Duxbury, 1983)

First occurrence of Vesperop-sis fragilis, V. mayi somewhat higher

First occurrence of Vesperopsis fragilis in the upper Hauterivian of South En-gland (Harding, 1986), V. mayi in the upper Barremian of Arctic Canada (Nöhr-Hansen, 1993)

Last occurrence of Hystrichod-inium solare

In the Subpolar Urals, forms of similar morphology are established in the low-er Hauterivian only (Lebedeva and Nikitenko, 1998)

Last occurrence of Oligo-sphaeridium ?asterigium

Last occurrence in the Turonian of northern Germany (Prössl, 1990); up to the Aptian in Canada (Bujak and Williams, 1978; McIntyre and Brideaux, 1980) and up to the Barremian in Greenland and Barents Sea shelf (Piasecki, 1979; Aarhus et al., 1990; Nöhr-Hansen, 1993; Smelror et al., 1998)

Last occurrence of Tenua Americana

Last occurrence in the mid-Hauterivian of northern Germany (Prössl, 1990)

Diversification of the genus Muderongia

See DK5 “diversification of Muderongia”

Diversification of the genus Batioladinium

In Volgian, Berriasian and Valanginian stages usually 1–2 species; in the Hau-terivian and Barremian 1–5 species; a sharp diversity increase is established in the lower Hauterivian of Greenland (Piasecki, 1979) and Barents Sea shelf (Aarhus et al., 1990); in the middle Barremian of the Barents Sea shelf (Smel-ror et al., 1998

Diversification of the genus Aprobolocysta

Single dinocysts of this genus are known from the Berriasian and Valanginian of northwestern Europe (Davey, 1982; Duxbury, 2001); beginning from the upper Hauterivian, several species (A. eilema, A. neista, A. trycheria, A. gale-ata, and others) persistently occur in England (Duxbury, 2001), Barents Sea shelf (Smelror et al., 1998), and Moscow basin (Iosifova, 1996)

Diversity decrease in the genus Oligosphaeridium

The genus diversity is highly variable in vertical and lateral directions

Lower boundary, Aptea anaphrissa–Oligosphaeridium aff. totum–Batioladinium longi-cornutum assemblage (DA6): the mid-lower Hauterivian

First occurrence of Aptea anaphrissa

First occurrence in the mid-lower Hauterivian of the Barents Sea shelf (Aarhus et al., 1990) and Subpolar Urals (Lebedeva and Nikitenko, 1998); since the up-per Hauterivian in Norway (Aarhus et al., 1986); significant since the Barre-mian in Canada (Williams et al., 1974; Jenkins et al., 1974; Bujak and Will-iams, 1978), Greenland (Nöhr-Hansen, 1993), and northwestern Europe (Dav-ey, 1979; Duxbury, 1977, 1980, 2001; A Stratigraphic…, 1992)

First occurrence of Banutiola-dinium longicortum

First occurrence in the lower Hauterivian of Norway (Aarhus et al., 1986); in the Subpolar Urals since the upper Valanginian (Lebedeva and Nikitenko, 1998); in Greenland and northwestern Europe since the Hauterivian (Piasecki, 1979; Davey, 1979, 2001; A Stratigraphic…, 1992)

First occurrence of Pseudo-ceratium sp.

In Greenland, P. pelliferum since the Berriasian (Piasecki, 1979); in England and North Sea shelf, P. pelliferum since the mid-Ryazanian (Davey, 1979; Duxbury et al, 1999; A Stratigraphic…, 1992); in Boreal Canada and Norway, P. pelliferum since the Valanginian (Bujak and Williams, 1978); in the Mos-cow syneclise, P. pelliferum since the Hauterivian (Iosifova, 1996); diversity is characteristic of the Barremian in Canada (Bujak and Williams, 1978; Nöhr-Hansen, McIntyre, 1998), Greenland (Nöhr-Hansen, 1993), Barents Sea shelf (Smelror et al., 1998), and Moscow basin (Iosifova, 1996)

First occurrence of Oligo-sphaeridium aff. totum

Oligosphaeridium totum since the Valanginian in Arctic Canada (Davies, 1983)

Note: Events observed at the same stratigraphic level in Siberia and different regions of north Europe and America are in bold.

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Batioladinium varigranosum in the mid-Berriasianprovides opportunity to correlate directly the base ofthe Pareodinioideae–Batioladinium varigranosum–Cassiculasphaeridia reticulata Zone with the lowerboundary of the Endoscrinium campanula Zone (VanHelden, 1986; Table 1). Owing to occurrence of Cyclo-nephelium cuculiform and Paragonyaulacysta ?borea-lis in the Berriasian assemblage, these zones of Siberiacan be correlated with the concurrent Cyclonepheliumcuculliforme–Paragonyaulacysta ?borealis Zone ofCanada (Davies, 1983; Table 1). The base of theEscharisphaeridia spp.–Oligosphaeridium spp. Zone,corresponding to the upper boundary of the Paragon-yaulacysta ?borealis–Dingodinium ?spinosum Zone inSiberia (Nikitenko et al., 2004; Table 1) is of a circum-Arctic geographic extent (Fig. 5, Table 4). Disappear-ance level of Dingodinium ?spinosum in Siberian sec-tions does not coincide with that boundary, beingrecorded somewhat lower at the Berriasian–Valangin-ian boundary. It is of interest that in northwesternEurope the youngest specimens of this species havebeen found at the same level. Consequently, disappear-ance of Dingodinium ?spinosum can be regarded asimportant criterion by defining the Berriasian upperboundary.

The first occurrence of Oligosphaeridium complexat the base of the Oligosphaeridium complex–Dingod-inium cerviculum Zone (Fig. 5) is an important indica-tion as well. In northern regions of Europe and Canada,this event was practically isochronous, being recordedat the base of the Buchia keyserlingi bivalve zone (Dux-bury, 1977, 2001; Bujak and Williams, 1978; Piasecki,1979; Davey, 1979; McIntyre and Brideaux, 1980;Davies, 1983; Aarhus et al., 1986; A Stratigraphic…,1992), i.e., at the same level as in Siberia. Oli-gosphaeridium complex, as a zonal index species, ismentioned only for the Tanyosphaeridium magneticumZone in Canada and Zone C in England (Table 1) thatprovides the direct correlation of their lower boundarieswith the base of Siberian zone.

Stratigraphic extent of the Tanyosphaeridium mag-neticum dinocyst zone is defined as corresponding tothe lower Valanginian and lower part of the upper Val-anginian (?), although the precise position of its lowerboundary has not been established (Davies, 1983). Theperformed stratigraphic analysis and correlation withthe corresponding palynostratigraphic subdivision ofSiberia, position of which is reliably defined in theBoreal standard (Zakharov et al., 1997), suggest thatthis boundary is approximately at the base of theBuchia keyserlingi Zone, i.e., at a somewhat higherlevel than the Valanginian base.

The Hauterivian and lower Barremian correlation lev-els are recognizable in Siberia and Western Europe. Char-acteristic components of the lower Hauterivian dinocystassemblages (presence of Hystrichodinium solare andincreased diversity and abundance of the genus Muderon-gia) are known besides from the Subpolar Urals (Lebe-

deva and Nikitenko, 1998). Species Aptea anaphrissaappearing at the base of the Aptea anaphrissa–Batioladin-ium longicornutum–Oligosphaeridium aff. totum Zonemarks the same level in the Subpolar Urals and BarentsSea shelf (Fig. 5, Table 4). Of a considerable stratigraphicand correlation potential is the lower boundary of theAprobolocysta eilema–A. neista–Odontochitina sp. Zone(Fig. 5). This level is marked by essential changes in taxo-nomic composition of dinocysts: it marks at once the firstoccurrences and extinctions of several species andincreased diversity of genera Muderongia, Aprobolocysta,and Batioladinium. Some of the palynological events arereadily recognizable in northwestern Europe as well(Table 4) that is important.

CONCLUSIONS

This study yielded new data on palynological char-acterization of Lower Cretaceous deposits in northernregions of West and Central Siberia. The resultsobtained and published data, which have been ana-lyzed, are used to define more precisely stratigraphicranges of about 130 dinocyst species and to distinguishgroups of stratigraphically important taxa, whichappear at practically concurrent levels in several north-ern regions of Eurasia and America (Table 3). Levels oftheir first or last occurrence can be regarded as impor-tant stratigraphic markers. Characteristic species ofdinocysts, which become widespread in particularstratigraphic intervals and determine the “face” ofrespective assemblage, give an important information.Ten biostratigraphic subdivisions ranked as dinocystzones are distinguished in the Berriasian–Barremiandeposits in northern regions of Siberia based on firstoccurrences of stratigraphically important taxa, higheror lower diversity degree of certain genera and families,and on compositional changes in groups of characteris-tic dinocyst species. In majority, boundaries of thesebeds are of a great correlation potential and can beregarded as reliable stratigraphic markers recognizablenot only in Siberia, but also in northern regions ofEurope and Canada. The dinocyst zones of the upperBerriasian, Valanginian, and lower Hauterivian are con-fidently correlated with the Boreal standard zones(Zakharov et al., 1997) and can be used, when neces-sary, for subdivision and dating the deposits in Siberia.The established biostratigraphic succession supple-ments and specifies the dinocyst zonation substantiatedin the Subpolar Urals (Lebedeva and Nikitenko, 1998)and extends upward the succession of dinocyst bio-zones characterizing the Upper Jurassic–lower Berria-sian section of the Nordvik Peninsula (Nikitenko et al.,2004; Table 1). The suggested subdivision scheme ofthe Lower Cretaceous based on dinocysts is includedinto the new regional stratigraphic chart for West Sibe-ria (Regional …, 2007).



ACKNOWLEDGMENTS

I am grateful to N.K. Lebedeva, V.A. Zakharov,B.L. Nikitenko and G.N. Aleksandrova for construc-tive criticism and valuable comments to the manu-script. I thank also Yu.I. Bogomolov, V.A. Kazanen-kov, V.A. Marinov, L.A. Glinskikh and O.O. Savchen-kova who donated samples for palynological analysis.The work was supported by the Russian Foundation forBasic Research, project nos. 06-05-64224 and 06-05-64291.

ReviewersG.N. Aleksandrova and V.A. Zakharov

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26. biostratigraphy of the mesozoic

Lithostratigraphy and biostratigraphy of the Lower ... · PDF fileLithostratigraphy and biostratigraphy of the Lower CretaCeous ... Key words: Lithostratigraphy, biostratigraphy, foraminifera,

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Jurassic Dinocyst Reference List - Revised Manuscript March 2012 Word 2003

12. BIOSTRATIGRAPHY OF EOCENE TO OLIGOCENE DEEP …Biostratigraphy The red clays from Site 767 are barren of calcareous microfossils, and shipboard biostratigraphy was based solely

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Dinocyst Biostratigraphy of the Lower Cretaceous in North Siberia …cretaceous.ru/files/pub/people/pestchevitskaya/07-dino... · 2018-01-17 · Novosibirsk, Russia Received June

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