THE FRASNIANIFAMENNIAN (MID-LATE DEVONIAN) BOUNDARY IN THE LONG RAPIDS FORMATION,

JAMES BAY LOWLANDS, NORTHERN ONTARIO, CANADA.

Bryan Geoffrey Levman

A thesis subrnitted in conforrnity with the requirernents for the degree of Master of Science Graduate Department of Geology

University of Toronto

O Copyright by Bryan Geoffrey Levman, 2001

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Abstract

The FrasnianlFamennian (rnid-Late Devonian) Boundary in the Long Rapids Formation,

James Bay Lowlands, Northern Ontario, Canada.

Bryan Geoffrey Levman Degree of Master of Science, 2001

Graduate Department of Geology, University of Toronto

The FrasniadFamennian (mid-Late Devonian) boundary has been located in the

Long Rapids Formation, northem Ontario. utilizing conodont-based biostratigraphy

and geochemistry. It was found in a black shale sequence 11 cm above a limestone

bed that has many simifarities to the Upper Kellwasser Limestone. a lithological

marker for the F/F boundary in Germany, Belgium and France.

There is no evidence for a sudden impact event, and sedimentation across the

boundary is continuous, although there is an erosional discontinuity just betow the

boundary and part of the lower Palmatolepis linguiformis Zone is missing. Strong

positive a13C and a'80 values were identified and are interpreted as evidence of a

m a s mortality in anoxic waters at the tirne of the FrasnianlFamennian extinction, an

event that was also accompanied by a ternperature drop. a% values also indicate

anoxia and a15N values provide evidence of reduced surface water productivity. No

iridium anomaly was found at the boundary.

Acknowledgments

I would like to thank my thesis supervisor, Professor Peter von Bitter, and cornmittee

members Professor Geoff Norris and Professor Andrew Miall for their direction, help

and encouragment in the formulation and completion of this thesis. The isotope

laboratory work was in part funded by an NSERC research grant to Professor Nonis.

For permission to use previously copyrighted material I would like to thank the

Ontario Geological Survey (Figure 1 ), the Canadian Society of Petroleum Geologists

(Figure 3) and the Geological Society Publishing House (Figure 13). 1 would also like

to thank Kathy David of the Royal Ontario Museum for her assistance with conodont

processing and a special thanks to my wife who accompanied me several times to

the Long Rapids Formation and helped with the collection of fossil material.

Table of Contents

Introduction ................................................................................................ 1

The Late Devonian FrasniadFamennian (F/F) Extinction Event ............................ 2

Canadian Sections containing F/F Boundary Beds ............................................. 4

......................................................................................... Regional Setting -7

The Long Rapids Formation ........................................................................ 10

Conodont Biostratigraphy ........................................................................... -13

The FrasnianlFamennian boundary in the Long Rapids Formation type section ...... 15

The Palmatolepis linguiformis Zone ............................................................... 19

Sedimentation Rate .................................................................................. -23

Conodont Taxonomy ................................................................................. 26

Conodont 'Pearls'. ...................................................................................... 33

Biofacies ................................................................................................ -35

Global Correlations ................................................................................... -37

........................................................................................... Geochemist ry -43

Trace Elements ................................................................................ -44

Iridium ............................................................................................ -46

........................................................................................... Carbon -47

Nitrogen .......................................................................................... -51

Oxygen ........................................................................................... -52

........................................................................................... Sulphur -55

Duration of the F/F Event ............................................................................ 58

Discussion .............................................................................................. -59

Summary.. .............................................................................................. -66

Systematic Palaeontology .......................................................................... -71

References.. .......................................................................................... -1 O1

List of Figures

Figure 1 : Location of Long Rapids Formation type section

in the Moose River Basin, northern Ontario, Canada ............................ ..6

Figure 2: Aerial view of Long Rapids Formation type section ................................ 8

Figure 3. Palaeozoic and Mesozoic stratigraphic units

in the Moose River Basin.. .............................................................. ..9

Figure 4: Top of Williams Island Formation type section and Long Rapids Formation

type section, stratigraphic column and location of samples.. .................. 12

Figure 5: Photo of FrasniadFamennian boundary strata

in the Long Rapids Formation type section.. ...................................... .17

Figure 6: Detailed sampling regime in the F/F boundary interval.. ........................ 18

Figure 7: Range chart of Palmatolepid conodonts in topmost portion of

Williams Island Formation type section and al1 of

Long Rapids Formation type section ................................................ ..20

Figure 8: Lag layer from base of unit 24 (Sample 20),

Long Rapids Formation type section.. .............................................. .22

Figure 9: lnferred evolutionary relationship

of five morphologically similar Palarntolepid species.. ........................... 28

Figure 10: Comparison of average element size in four related

Palmatolepid species recovered.. ................................................. ..29

Figure 11 : Percentage of conodont Pa elements by Genus. ............................... 36

Figure 12: Comparison of Long Rapids Fm. type section and Hony (Belgium).

Sinsin (Belgium). and Steinbruch Schmidt (Germany)

FIF boundary sections.. ............................................................... .39

Figure 1 3: Late Devonian (Famennian) palaeogeography

and location of F/F sections.. ........................................................ .40

Figure 14: Comparison of Long Rapids Formation type section and Sessacker

trench carbonate strata just below the F/F boundary .......................... 42

Figure 15: Percentage composition carbon and carbon isotope ratios

in the F/F boundary strata, Long Rapids Fm. type section.. ................. .50

Figure 16: Oxygen and nitrogen isotope ratios in the FIF boundary strata,

Long Rapids Fm. type section ..................................................... ..53

Figure 17: Percentage composition sulphur and sulphur isotope ratios

in the F/F boundary strata, Long Rapids Fm. type section.. ................. .57

List of Plates

Plate 1.. ................................................................................................ -126

Plate 2.. ................................................................................................ -128

Plate 3.. ............................................................................................... ,130

List of Tables

Table 1: Selective Geochemical Sampling of the Long Rapids

Formation type section.. ............................................................... .132

Graph of Data from Table 1 ........................................................................ 133

Table 2: Conodont Distribution Data for Range Chart ..................................... -134

Table 3: Cornparison of Average Conodont Size ............................................ 135

Table 4: Whole Rock Analysis of Boundary Strata .......................................... 136

Graph of Data from Table 4 ........................................................................ 137

Table 5: Trace Elernent Analysis of Boundary Strata ....................................... 138

........................................................................ Graph of Data from Table 5 139

Table 6: Trace Element Analysis of Boundary Strata ....................................... 140

.......................................................................... Table 7: t ridium Content -141

............................................................. Graph of Data from Tables 6 and 7 142

vii

Introduction

Extinction events have fascinated scientists for the last two centuries. In question

are some fundamental issues about life that have interested scientists since

Georges Cuvier, Charles Darwin and Charles Lyell: does evolution proceed

gradually or uniformly (Lyell, 1830. 1832; Darwin, 1859) or by fits and bounds

(Cuvier, 181 2; Eldredge and Gould, 1 972: Ager, 1 993)? Do extinctions happen

because of maladaptation to a gradually changing environment (Dawkins, 1988), or

the 'bad luck' of being in the wrong place at the wrong time (Raup, 1991)?

For decades Charles Darwin's and Charles Lyell's unifonnitarian views held sway;

however, by the 1970s credible altemate models were being proposed (McLaren,

IWO; Eldredge and Gould, 1972). The Late Devonian FrasnianlFamennian mass

extinction was first quantified by Newell (1 967), and McLaren (1 970) suggested that

the extinction event was caused by a bolide impact, creating global marine turbidity,

decimating the shallow water benthos. McLaren challenged geologists to precisely

define what happened at these major faunal turnovers, because they fom the basis

for calibrating geological time.

3 - Alvarez et al. (1980) found enriched levels of siderophile elements such as Ni, Co,

Pt, and Ir (that are concentrated in iron meteorites and the earth's mantle) at the

Cretaceous-Tertiary Boundary in ltaly and Denmark. They hypothesized that this

was the residue of a carbonaceous chondrite that hit the earth, pulverized and

diffused into the atmosphere; this blocked the sunlight to such an extent that

photosynthesis was suppressed for several years, disrupting the marine and

terrestrial food supply and causing a major extinction event. Subsequently a great

deal of scientific research has been conducted to test the irnpactlkill hypothesis at al1

the extinction events of the Phanerozoic, including the FrasniadFamennian.

The Late Devonian FrasniadFamennian (WF) Extinction Event

The Late Devonian is divided into two stages, the Frasnian and Famennian (Harland

et al.. 1990). Based on conodont biochronology, Sandberg and Ziegler (1 996)

hypothesized that the duration of the Frasnian was approximately 5 million years,

from 369 to 364 m.y.a. and the duration of the Famennian approximately 10 million

years, from 364 to 354 m.y.a. (contra Harland et al., [1990] who effectively reversed

these figures, i.e. the Famennian and Frasnian equalled 4 and 10 million years,

respectively). At the FrasniadFamennian boundary, an enorrnous drop in species

3

diversity has been document& (Newell, 1967; Sepkoski, 1986; McGhee, 1996) with

up to three-quarters of al1 species on earth disappearing, making it one of the 'big

five' extinction events in the Phanerozoic. Major groups affected include rugose and

tabulate corals, stromatoporoids, ammonoids. trilobites, foraminiferids, conodonts,

fishes and land plants. Numerous F/F boundary sections around the world have

been studied in North America, Australia, Europe, North Africa and Asia and most

researchers agree that anoxia, probably caused by oceanic overturn, was an

immediate cause of the extinction of manne animals. During oceanic overtum the

density stratification of the ocean is disrupted and poisonous, sulphide nch anoxic

bottom waters rise to the surface, destroying manne habitats (McGhee, 1996). Some

suggest the triggenng mechanism resulted from a bolide impact (Sandberg et al.,

1 988, McLaren and Goodfellow, 1 990; Geldsetzer et al., 1993; Wang et al., 1 996);

others suggest that tectonic forces were ultimately responsible (Schindler, 1990a. b;

Racki, 1998a, b). Other possible killing mechanisms include climatic cooling

(Copper, 1986, 1 998); warrning (Thornpson and Newton, 1988); eustatic sea level

changes (Qiang, 1989, Muchez et al., 1 996); and toxic eutrophication caused by

hydrothennal megaplumes (Racki, 1998a), or increased nverine nutnent flux (Algeo

4

et al., 1995). Many of these causes may be interrelated, possibly in a complex

fashion. This will be explored in greater detail below.

This study focuses on a FrasniadFamennian section in the Long Rapids Formation

type section, located in a remote part of northem Ontario south of James Bay. The

section was visited over three successive surnrners during 1997-1 999 and the

biostratigraphy gradually refined using conodont biochronology to isolate the faunal

turnover by which the F/F boundary is recognized (Klapper et ab, 1993). The

stratigraphic level of the boundary was later confirmed using geochemical and

isotopic tests. Iridium was also analyzed for so as to ascertain whether there was

any evidence for a sudden catastrophic impact event, and to understand the sudden

or gradua1 nature of the boundary change. The Long Rapids Formation data was

then compared with that from other key sections around the world.

Canadian Sections containina F/F Boundarv Beds

Three other known Canadian sections contain the FrasniadFamennian boundary:

Trout River, Northwest Territories, a platfon carbonate shelf deposit (Orchard,

1988; Geldsetzer et al., 1993) where, however, the lowest Palmatolepis triangularis

5

Zone that defines the base of the Famennian is missing; Cinquefoil Mountain. a

carbonate upper-slope sequence near Jasper, Alberta; and Medicine Lake, an inter-

reef basinal setting, also near Jasper (Wang et al., 1996). The boundary may also

be present in the Besa River Shale of northeast British Columbia (Pelzer, 1966). In

Ontario, the boundary may also occur in the Kettle Point Formation of southwestern

Ontario (Winder, 1966).

The Long Rapids Formation type section is located about 25 km north of the

hydroelectric dam at Otter Rapids and about 1 km south of Williams Island on the

Abitibi River, about 760 km north of Toronto. It is most easily accessible by canoe or

helicopter (Figure 1 ). GPS data indicate that the formation outcrops at 500, 23'. 25"

N, 81 O, 3 4 , 15" W (UTM 598826) and extends south-southwest along the river bank

to 50". 23' 08" N, 810, 34'. 46" W (UTM 595822). Since the Abitibi River is a major

drainage channel for the James Bay Lowlands, water level of the river can Vary

significantly each summer, depending upon precipitation and damming by the

hydroelectric facility at Otter Rapids. Since the river is flooded at unpredictable

times to generate hydroelectnc power for urban centres to the south, sampling

conditions are quite difficult and even dangerous, as water levels rise very fast.

Figure 1: Location of Long Rapids Formation type section, in the Moose River Basin, northem Ontario, Canada. Modified from Ontario Geological Survey, 1991.

Paleozoic and Mesozoic Depositional Sequences and Events in Ontario. Map 2582. Figure 1. (Thurstone et al., 1991). Used with permission.

The boundary beds outcrop at the northem end of the section (location "û" in Figure

2). This is the type section of the Long Rapids Formation; the formation is also

known frorn core (Sanderson and Telford. 1985) the conodonts of which are

currently being studied by Drs. Gilbert Klapper and Tom Uyeno of the University of

Iowa and the Geological Survey of Canada, respectively.

Regional Setting

The Long Rapids Formation was deposited in the Moose River Basin, an

intracratonic downwarping caused by horizontal transmission of stresses from the

plate-margin Appalachian orogenic collision-event (Williams et ai., 1992; Sanford.

1987). The Basin underlies an area of about 100,000 km2 and contains

approximately 700 m of Middle Ordovician to Upper Devonian strata, consisting

chiefly of manne carbonates, shales, evaporites and minor manne and continental

clastic rocks (Telford, 1988) (Figure 3). The Long Rapids Formation is the youngest

Palaeozoic lithostratigraphic unit in the Basin and represents the last recorded

manne transgression in the area (Sanford, 1987). Following regression, the Long

Rapids Formation was subjected to extensive tectonism. including faulting. folding

Air Photo from Ontario Ministry of Natural Resources, 94-50 1 3 1 6-269

Figure 2: Aerial v i e ~ of Long Rapids Formation type section A = Top of exposed Long Rapids Formation, B = F/F boundary outcrop, C = Base of L m Rapids Fornation,

D = Top of exposed Long Rapids Fomiatim

ORDOVICIAN SlLURl AN DEVONIAN

1 UPPER LOWER 1 UPPER LOWER 1 MIDDLE

10

and ultramafic intrusion (Acres International Ltd., 1989); at least one dyke, just

upstream at Coral Rapids, was dated as Late JurassicIEarly Cretaceous (Sanford

and Norris, 1975).

The Long Rapids Formation

The Long Rapids Formation is the lithostratigraphic, but not necessarily the

chronostratigraphic equivalent of other Upper Devonian organic-rich black shales of

eastem North America such as the Ohio, New Albany, Chattanooga and Antrirn

shales of the United States. In southwestem Ontario, the correlative unit is the Kettle

Point Formation (Telford, 1988). The basinal setting, shale lithology and the

conodont fauna suggest that the Long Rapids Formation was deposited in a lower

dope environment. In core, the Long Rapids Formation is up to 79.3 m thick

(Sanderson and Telford, 1985), but in outcrop oniy about 35 metres are exposed

(contra Bezys and Risk, 1990; contra Bezys, 1991 ; Norris et al., 1992).

Although younger than the underlying Williams Island Formation, the Long Rapids

Formation at the type locality is topographically lower because of an anticline and/or

fault that has pushed the Williams Island Formation higher (Sanford and Norris,

1975). The formation outcrops on the flanks of the southwest plunging Williams

Island dome and dips southeast. The upper beds repeat at the beginning and end of

the outcrop due to folding (Figure 2). Overlying the shales and carbonates of the

Long Rapids Formation are Mesozoic sediments of lacustrine and fluviatile origin

(Norris, 1 986).

The Long Rapids Formation type section consists of altemating green mudstone and

black shale beds containing up to twelve thin carbonate interbeds, incfuding three

containing massive concretions (Figure 4). The concretions are similar to those

found in the Kettle Point Formation of southem Ontario (Cameron and Coniglio,

1990), consisting of a dolomite micritic matrix infilled with coarser calcite and

dolomite; some have septarian structure in the centre. The carbonate beds of the

Long Rapids Formation type section have been dolomitized and show dark organic

staining in a lighter medium gray matrix, indicating a reducing environment. In

places, wom burrows are present. There is also pyrite present, which suggests an

hypoxic environment, if the pyritization is syngenetic. Geochemically the carbonate

rocks are argillaceous dolomitic limestones containing about 10-1 5% Mg0 and 15-

13

30% Si02 (Table 1). Petrographically, they are a neomorphic microbiospante

mudstone or wackestone.

Conodont Biost ratiara~hv

The carbonate beds of the Long Rapids outcrop were initially sampled for

conodonts; once the boundary interval was identified, more closely spaced samples

were taken of both carbonate and shale beds. All samples were processed using

10% formic acid and standard heavy liquid separation techniques. Black shales are

not usually processed with formic acid, but their high Ca0 content (Table 4) made

them amenable to disaggregation in this manner. All parts of conodont apparatuses

were recovered, but most non-plafform elements could not be identified to species

because of their vicarious nature (Klapper and Philip, 1971 ; Ziegler and Sandberg

1990). The biozonation of the Long Rapids Formation type section is based on Pa

elements, arguably the most rapidly evolving of the septirnembrate polygnathid and

palmatolepid apparatuses (Nicoll, 1987). In the Long Rapids Formation type section,

as elsewhere, Pa elements are better preserved, and more commonly recovered

than are other parts of the apparatus.

14

As well as abundant conodonts, there are other organisms present in the Long

Rapids Formation type section. Phosphatic brachiopods, tentaculitids (Homoctenus

spp.), and minor vertebrate rernains were also recovered. The goniatite bed

onginally reported by Savage and Van TuyJ (1 91 9), and later rediscovered by

Russell and Telford (1984), was found but could not be placed in the section

because of structural complications. Bezys and Risk (1 990) located the goniatite bed

at 10 m above the base in the tower part of the formation suggesting it occurs in the

mid-Late Palmatolepis rhenana Zone. This may correlate with unit 7 (Figure 4)

where a partial goniatite was found. Other goniatite finds (unit 4 in Figure 4) indicate

that there are rnay be more than one goniatite-bearing bed in the Long Rapids

Formation type section.

The lowest part of the section exposed at low water in the southem part of the

section at Long Rapids (location "C" in Figure 2) is the top of the Williams Island

Formation type section; the Long Rapids Formation type section is defined and

recognized by the first appearance of dark shale (Nonis et al., 1992). The top of the

Williams Island Formation type section strata contains the fauna of the upper Early

Palmatolepis rhenana Zone (Ziegler and Sandberg, 1990) or the beginning of the

15

Late Palmatolepis henana Zone, as the index fossil for the latter (Palmatolepis

rhenana rhenana) appears just below the base of the Long Rapids Formation type

section (Table 2). Palmatolepis foliacea is rare at the top of the Williams Island

Formation type section, suggesting that the basal Long Rapids Formation type

section contains a conodont fauna of the early part of the Late Palmatolepis henana

Zone as it is within the latter zone that the end of the range of Palmatolepis foliacea

occurs (Ziegler and Sanderg, 1990). The disappearance of Palmatolepis foliacea

(Table 2 ) is also an index for the lowerrnost part of Zone 13 of Klapper and Foster

(1993), which would place the Long Rapids Formation type section in that zone,

approximately equivalent to the Palmatolepis linguiformis Zone of Ziegler and

Sandberg (1 990).

The FrasniadFamennian boundarv in the Lonq Rapids Formation t v ~ e section

The FrasniadFamennian boundary area is found just above units 20 and 22, two

carbonate beds, each about 0.25 metre, that pinch and swell laterally (Figure 4).

Units 20 and 22 are separated by a 16 cm calcareous green mudstone interbed (unit

21) and are succeeded by a 9 cm calcareous green mudstone (unit 23) and a 4

16

metre thick succession of thinly laminated, calcareous, pyritic black shale that lacks

bioturbation (unit 24) (Figures 4, 5). The boundary occurs in the lower part of the

black shale section (Figure 5). 21.46 metres above the base of the section (contra

Telford [1985] in Norris et al. [1992:17]), and one to two cm above the base of the

black shale.

21.44 m above the base of the Long Rapids Formation type section Palmatolepis

linguiformis, the index fossil for the uppermost Frasn ian Palmatolepis linguiformis

Zone, first appears at the base of Unit 24. About 1 to 1.5 cm above that fossil's first

appearance, the index fossil for the Famennian, Palmatolepis triangularis, appears

and only one cm higher it occurs in significant quantities (Figure 6). The lowest part

of unit 24A was further divided into sample 20 (the lowest 1-1.5 cm) and sample 21

(the rernaining 9 cms) based on the first visible appearance on shale surfaces of the

Famennian index fossil, Palmatolepis triangularis ; however, Pa. subrecta is present

in the early part of sample 21, and is not completely absent until sample 22, just 10

cm above the base of sample 20. Others have also reported the survival of Frasnian

species into the lower part of the Famennian (Schülke, 1998). and the official

Figure 5: Photo of FrasniadFamennian boundary strata, in the Long Rapids Formation type section. Apparent pinching out towards right is

caused by different planes of view and photographic angle.

unit :

unit :

unit 2

[ --"..,.- .;,, Palmatolepis rhenana Zone

21.74

21.69

21.59

21 .!3

Fff bol

21 -44

Figure 6: Detailed sampling regime in the F/F boundary interval.

19

(Subcommittee on Devonian Stratigraphy or SDS) definition of the boundary is the

"abundant or flood occurrence of Palmatolepis triangulans, to the virtual exclusion of

other species of the genus, stratigraphically above the fauna dominated by the

characteristic upper Frasnian species" (Klapper et al., 1993). Ziegler and Sandberg

(1996) recognized the boundary by the "entry of Palmatolepis triangularis," a

definition that in the Long Rapids Formation type section would place it at the base

of sample 21 ; however, the SDS definition would place it about one cm above the

base of sample 2 1 , where Pa. subrecta (= Pa. winchelli) dies out. (Figures 5, 6, 7).

The Palmatole~is linuuiformis Zone

The Palmatolepis linguiformis Zone in the Long Rapids Formation type section

consists of only 2 cm (sample 20 [one cm] and the first cm or so of sample 21), while

the Late rhenana Zone encompasses over 20 meters. Chrono- and probably

lithostratigraphically, the Palmatolepis linguifomis Zone is much shorter than the

Palmatolepis rhenana Zone; Sandberg et al. (1 988) and Ziegler and Sandberg

2 1

(1 996) assigned a duration of .3 million years to the former and .7 to the latter, and

other authors (e.g., Joachimski and Buggisch, 1993) showed the Palmatolepis

linguifonnis Zone as only a small fraction of the thickness of the Palmatolepis

rhenana Zone. The influx of icriodid species in the Palmatolepis linguiformis Zone

may suggest shallower waters at this time (Seddon and Sweet, 1971 ) which could

also result in a period of extremely limited sedimentation or even sediment starvation

and erosion. There is evidence of erosion at the base of unit 24, at the lower contact

with the underlying green mud layer. Here a discontinuity lag layer and hardground

(Miall, 1984; Allaby and Allaby, 1990) are present, replete with conodont pearls

(phosphatic microspherules associated with conodonts), topmost Frasnian

linguifonnis Zone con odonts incl uding the index fossil Palmatolepis linguiformis,

homoctenids, and pyritized worm burrows (Figure 8). This layer (unit 24) has a

carbonate content (10.25%) over twice that of the underlying strata and a

manganese content of 1057 pprn, significantly higher than the 791 ppm average of

the boundary area beds (Table 6). Baird and Brett (1 986) interpreted similar pyritic

and fossil concentrations as due to subaqueous erosion under reduced oxygen

conditions associated with a marine transgression. How much of the linguifonnis

Zone is rnissing is not known; however, it is clear that the critical boundary section is

Figure 8: Lag layer from base of unit 24 (Sample 20), Long Rapids Formation type section, showing conodont (C)

and homoctenid (ribbed cone-like fossils) accumulations.

present in the lower part of unit 24A (samples 20 and 21). as there is a smooth

transit ion between Palma tolepis subrecta and Palmatolepis triangularis.

Sedimentation rate

Ricken (1 991 :786) suggested a method of assessing the length of the hiatus

represented by a lag deposit, a method that he ternis "enrichment of relic

constituents." This procedure involved counting the number of fossils concentrated

in the lag deposit. Assuming the fossils were winnowed from the unit below. he then

calculated how much sediment would have to have been eroded to account for the

deposit. In the Palmatolepis linguiformis Zone of the Long Rapids Formation type

section the total conodont numbers exceed 5441 specimens for sample 20 (onty 1

cm) and 1053 specimens for the underlying sample 19, consisting of 9 cm or roughly

100 for each cm. Since both samples processed are approximately the same weight

(20009 for sample 19 and 18989 for sample 20), sample 20 contains over 50 times

more fossils per cm than sample 19. This could suggest that approximately 50 cm of

strata were eroded away and winnowed to produce the overlying lag layer.

containing ,5441 conodonts. Based on a sedimentation rate of 0.01 mm /year (see

24

below), this might represent only 50.000 yean of missing time, which would mean

that the majority of the Palmatolepis linguiformis Zone is represented in 2 cm of

strata. This, in fact, is possible as extreme stratigraphic condensation is a

characteristic feature of FIF boundary sections (Morrow, 2000) and different

lithologies are being compared. Unit 23 is a green mudstone whereas unit 24 is

primarily fissile shale.

Miall (1997) has pointed out that sedimentation rates Vary by an astonishing eleven

orders of magnitude. depending upon the depositional environment and subsidence

rate. Subsidence rates Vary anywhere between 0.3 and 2.5 mm per year in

sedimentary basins (Allaby and Allaby, 1990). Various authors have tried to relate

these two factors to the FIF boundary strata in order to understand the duration of

the extinction event (Sandberg et al., 1988; Geldsetzer et al., 1993; Bratton et al.,

1999). A consaivative sedimentation rate estimate for the basinaVlower slope

depositional setting in an epeiric basin might be O. 1 mm per year (Ricken, 1991 :782),

leading to an estimated duration of about 214,000 yean for the Later Palmatolepis

menana Zone in the Long Rapids Formation type section. This compares with a

700,000 year estimate by Sandberg and Ziegler (1 996) for the Late Palmatolepis

menana Zone. Using this sedimentation rate the linguiformis zone strata of only 2

crns would represent only 200 years; however, there has been significant erosion of

this section, as indicated by the discontinuity at the top of unit 23 and the base of

unit 24 and there is a further erosion surface at the top of unit 20 which has been

planed virtually flat, in the Late Palmatolepis henana Zone. Even if the postulated

sedimentation rate were reduced to 0.01 mrn/year for the Palmatolepis linguiformis

Zone strata - the approximate rate that Sandberg et al. (1 988) used in their

calculations for the Gerrnan Steinbruch Schmidt section - the timespan involved

would be only 2,000 years. The duration for the F/F "extinction layer" at Steinbruch

Schmidt was calculated to be between 1 2,500 and 47,000 years, based on that

sedimentation rate. Wang et al. (1 996) calculated a sedimentation rate of 46 m/m.y.

(0.046 rnm/year) for sections in Alberta and compared this to calculated rates of 1.3

rn/m.y. (.O01 3 mmlyear) for some European sections (data from Jaochimski and

Buggisch, 1993) and 5.9 m/m.y. (0.0059 mm/year) for Chinese sections (from Wang

et al., 1 991 ). Applying the European rates to the linguifomis zone at the Long

Rapids Formation type section suggests that the 2 cm would have taken about 15

thousand years to deposit. It is. however quite likely that much more time is

26

represented than these calculations suggest, because of sediment starvation, non-

deposition and erosional hiatus.

Conodont Taxonomv

None of the conodonts recovered from the Long Rapids Formation type section are

either unexpected or controversial except possibly for Palmatolepis praetriangularis

Ziegler and Sandberg. This species was recognized and described by Sandberg et

al. (1 988) as the direct ancestor of all Famennian palmatolepid species. The only

difference between praetriangularis and tfiangularis is the dope of the posterior

platfonn of the Pa element; that cf ppraetriangulafis is flat or downward sloping, while

that of triangularis rises. Palmatolepis praetriangularis ranges from "within the

linguiformis Zone into the Middle triangularis Zone" (Ziegler and Sandberg, 1990).

Klapper et al. (1 993) challenged the validity of the taxon and synonymized

praetnangulark with its supposed progeny; Schülke (1 995; 1998) synonymized it

with Palmatolepis hassi. This study does not support either position, as

praetriangularis appean to be a distinct species from triangularis, ranging

th roug hout the Late Palmatolepis rhenana and Palmatolepis linguiformis Zones, into

27

the bottom of the overlying Palmatolepis triangularis Zone; it is also morphologically

distinct from Palmatolepis hassi. The species has not previously been reported from

the Late rhenana zone in any numbers (e.g. Morrow, 2000, table 12; in the latter

study, one bedding plane occurrence of Pa. praetriangularis was noted in the Late

Palma tolepis rhenana Zone).

Pa. praetriangularis Pa elements are variable in the Long Rapids Formation type

section, intermediate in morphology between Palmatolepis hassi, Pa. subrecta and

Pa. rotunda, which are al1 believed to have belonged to the same gene pool (Ziegler

and Sandberg, 1990:42) (Figure 9). Many of the variants recovered from the Long

Rapids Formation type section are similar or identical to Palmatolepis

praetriangularis as illustrated by Sandberg et al. (1 988, plate 1 , figures 1 -4). Over

half of the Palmatolepis praetriangularis Pa elements are juvenile and rnost mature

specimens are small (average 0.64 mm) when compared to the related Palmatolepis

hassi, Pa. subrecta and Pa. rotunda Pa elements recovered (average 1.051.801.70

mm, respectively; Figure 10). One possibility is that Palmatolepis praetriangularis is

simply an immature form of the Palmatolepis subrecta/Pa. rotundaPa. hassi trio;

Pa. triangularis

. praetriangularis

Time

Figure 9: lnferred evolutionary relationship of five morphologically similar Palmatolepid species(after Sandberg and Ziegler, 1 990:42).

N = 50 Y

Average size 1.05 48

Pa. hasa Pa element

N = 162

Average size 0.70

Pa. rotunoh Pa element

N=286

Average size 0.80

Pa. subrecta Pa element

Pa. praetriangularis Pa element

Figure 10: Cornparison of average element size in the four related Palmatolepid species recovered

30

however, the 51 3 mature specimens (Table 3) make this unlikely. A more plausible

hypothesis is that Palmatolepis praetriangulariç is a valid species that has evolved in

response to the Late Devonian environmental fluctuations. This interval of time was

a period of great environmental stress, stress that started much earlier than the

Frasnian-Famennian event (Schindler, 1993; Racki, 1 998a). Faunal extinctions

began in the Late rhenana Zone and are recorded in the Lower Kellwasser

Limestone in Germany and France. The reefal ecosystems throughout Europe were

decimated (McGhee, 1996). although the extinctions recorded in the Upper

Kellwasser Limestone were much more severe. Evidence for earlier extinction

events has not been located in the Long Rapids Formation type section; however.

the black shale lithology and general paucity of megafossils demonstrate that the

habitat was likely hypoxic and under stress.

The Moose River Basin's only connection to the main epicontinental ocean that

covered most of the eastern United States and southem Ontario in the Devonian

was via a narrow seaway (Sanford, 1987; Johnson et al., 1992); during the

Phanerozoic this connection was periodically severed because of epeirogenic uplift

of the Frontenac and Fraserdale arches. and marine regressions. An end-Frasnian

3 1

marine regression recorded in the Long Rapids Formation type section (see below)

may well have geographically isolated the Moose River Basin. providing a fertile

'breeding ground' for the development of allopatric species (Mayr, 1988). In stressful

environments, species adopt 'proportioned dwarfism' as a strategy to adapt to a

radically changing environment (Gould, 1977). This would explain the smaller size of

Palmatolepis praetriangularis; examples of this adaptation during the

FrasnianIFamennian were previously documented by Schülke (1 998) for

palmatolepid species and Renaud and Girard (1 999) for palmatolepid and icriodid

species. Smaller body size, together with progenesis. early sexual maturity. and

high fecundity are a natural survival response to times of environmental stress.

Speedy maturation and the production of abundant offspring, with lots of genetic

variation and mutation potential, are typical of r-selection (Abercrombie et al., 1992),

which favours organisms that increase more rapidly (r=intrinsic rate of increase), can

colonire quickly and can make use of short-lived resources. A mutant Palmatolepis

sp. Pa element found in the Long Rapids Formation type section (PI. 2 fig. 18) would

support this hypothesis, although Sandberg et al. (1 997) preferred to attribute the

various mutations obsewed around the F/F boundary to cosmic radiation.

32

It should be noted that the data of Renaud and Girard (1999) disagree somewhat

with that of this study. These authors reported that Palmatolepis praetriangularis has

"approximately the sarne size" as Palmatolepis rotunda and Palmatolepis subrecta

and that al1 three species decrease in size at, or just above the Upper Kellwasser

Limestone in the FIF type section at the Coumiac quariy in southem France. This

study shows no significant change in platfom size through time for any of these

species (Table 3), but does show consistent size difference between

praetriangularis and its progenitor group thoughout the Long Rapids Formation type

section. The difference in the number of elements avaitable for measurement is

perhaps significant, with the Long Rapids Formation type section database almost

eight times larger than that of Renaud and Girard for Palmatolepis praetriangularis

(51 1 :65), over three times larger for Palmatolepis hassi (50:16) and Palmatolepis

rotunda (1 6252) and twice as large for Palmatolepis subrecta (286: 143). Also,

whereas this study used the length of Pa elements as a size index, Renaud and

Girard did a Fourier transform of the entire Pa platfom, calculating a circle diameter

with the sarne area as the platform, and used that as a measure of size. Although

this is more accurate, with palmatolepids the length of the Pa element is proportional

to surface area, and is an adequate proxy for overall size.

Conodont 'Pearls'

Calcium phosphate spheres occur intemittently throughout the Long Rapids

Formation type section but are particularly abundant around the

FrasniadFamennian boundary beds. More than 2000 specimens were recovered

from samples 20 and 21 in the boundary shale. almost two orders of magnitude

more than the numbers found elsewhere (a maximum of 40 found in sample 18) in

the Long Rapids Formation type section. Above sample 21 (unit 24A) they drop off

sharply to single digit counts and then disappear in the Famennian (Table 2.

samples 23-28)

The largest number of 'pearls' was found in sarnple 20 which contains the lag

concentrate from the Palmatolepis linguifomis Zone. The FIF boundary is found in

sample 21 and although it contained 254 'pearls', it is almost an order of magnitude

lower than the subjacent unit, but almost an order of magnitude higher than any

other unit in the Long Rapids Formation type section. Nor does the incidence of

pearls appear to be related to lithology, as they are present in both shale and

carbonate beds (e.g., sample 18). and absent in both as well (e.g., samples 26-28).

34

That there is a concentration of these fossils at the latest Frasnian and at the actual

boundary is undeniable, but their significance is unknown, as we do not understand

what part of the organism they represent, or even if they are part of the conodont

animal. They have never been repoited in the literature without conodonts also

being present.

Glenister et al. (1 976) hypothesized that the 'pearls' were secretions by the

conodont animal in response to an organic or particulate irritant. They thought that

this might be a parasite, as they are the most common stimulus for similar

fomiations in bivalves. The 'pearls' when tested, showed the same calcium,

phosphatic composition as conodonts. Although most of the 'pearls' occurred in

black shale, there appears to be no lithological correlation as other black shale

samples (e.g., samples 22, 24) yielded very few of the 'pearls'. The proximity of the

large number of pearls to the F/F boundary might lead one to hypothesize a bloom

of infesting organisms as a kill mechanism. perhaps caused by a eutrophic

environment (Algeo et ab, 1995; Racki, 1998a). but aside from the 'pearl' spike,

there is no other data to support this theory (PI. 3, figs. 15-1 9).

Biofacies

Continuing the work of Seddon and Sweet (1971), Sandberg (1976) recognized

Devonian conodont biofacies in five biofacies belts; subsequently, Sandberg and

Dreesen (1 984) broadened it furtber to include nine biofacies. Their biofacies model

is useful for understanding water depths and distinguishing between pelagic and

nearshore environrnents. The palmatolepid-polygnathid biofacies is the second most

offshore biofacies that Sandberg and Dreesen (1 984) interpreted to represent a

middle to upper slope environment. The two genera must constitute at least 70 per

cent of the fauna to qualify as a biofacies under this interpretation (Sandberg et al.,

1988). The only biofacies present in the Long Rapids Formation type section is the

palrnatolepid/polygnathid biofacies, although numbers of icriodids are present in the

Williams Island Formation type section (samples 1-7 in Table 2) and in the boundary

shale (al1 the samples from unit 24, Le., samples 20-26 in Table 2).

Figure 1 1 shows the changing percentages of ancyrodellid/ancyrognathid.

palmatolepid, polygnathid and icriodid species throughout the Long Rapids

Formation type section, based on Pa elements. Note the icriodids in the upper

Sample 28 Sample 27 Sample 26 Sample 25 Sample 24 Sample 23 Sample 22 Sam le 1

~aund)ar~f?k Sample 20 Sample 19 Sample 18 Sample 17

Sample 16 Sample 15 Sampie 14

Sample 13 Sample 12 Sample 11 Sample 10 Sample 09 Sample 08 Sample 07 Sample 06 Sample 05

Sample 04 Sample 03 Sample 02 Sample 01

m icriodid Pa elements

Palmatolepid Pa elements

Figure 1 1 : Percentage of conodont Pa elements by Genus

Fff boundary occurs at me base of Sample 21 a AncyrodeNidl

Ancyrognat hid Sarnple 26 contained only 7 Pa eiements Pa elements

a7] Poiygmthid Pa elements

37

Williams Island Formation type section and increase in icriodid numbers just below

and above the FIF boundary. In al1 samples but one (sample 26 which had only 7 Pa

elements recovered) palmatolepid and polygnathid Pa elements combined represent

over 80 per cent of the platform genera. The icriodid increase at the FIF is indicative

of changing environments in the upper Frasnian and lower part of the Famennian.

Global Correlations

The changing icriodid percentages and the discontinuity surfaces at the top of unit

20 (Late Palmatolepis rhenana Zone) and the base of unit 24 (Palmatolepis

linguifomis Zone) suggest a short, sharp regressive pulse or shallowing upward

trend just before the boundary. This trend has been identified elsewhere (Sandberg

et al., 1988) and has been interpreted to be synchronous with a global anoxic event

causing the F/F extinction (Goodfellow et al., 1988; Morrow, 2000). The Upper

Kellwasser Limestone, widely distributed in Germany, Belgium and France, is

associated with this extinction horizon (Schindler, 1990b, 1993). The Upper

Kellwasser rocks consist of dark mudstones and wackestones intercalated with dark

marly shales (Schindler and Konigshof, 1997; Schindler et al., 1998) and the top of

38

the Upper Kellwasser Limestone has been identified as the FrasnianIFamennian

boundary by many researchers (Sandberg et al., 1988: Joachimski and Buggisch,

1993). Lithologically, the uppermost Long Rapids Formation type section carbonate

beds (units 20 and 22 in Figures 4 and 5) containing Frasnian conodonts are similar

to some of the European and North American sections of the Upper Kellwasser

Limestone. Three sections, Steinbruch Schmidt in Gemany and Hony and Sinsin in

Belgium show many similarities with the Long Rapids Formation type section, in

termç of altemating carbonate and marly shale lithologies (Figure 12) and increasing

icriodid presence, indicating sea-level and environmental changes. A microtektite

layer was also reported at the Hony section (Claeys et al.. 1996); there is, however,

no conodont control at Hony and the layer cannot be definitely placed at the

boundary. No similar microtektite layers were found elsewhere in European locales

nor in the Long Rapids Formation type section, despite their geographic proximity to

each other during Late Devonian times (Figure 13). The global stratotype for the FIF

boundary at Coumiac, France shows a possible hiatuddiscontinuity surface similar

to that in the Long Rapids Formation type section, a surface that has been

interpreted (Ziegler and Sandberg, 1996; Schindler and Konigshof, 1997) to indicate

the erosion of part of the Earîy Palmatolepis triangularis Zone, probably

microtekt layer

Unit 24 -

Unit 23 -

F/F Boundary œ œ

Long Rapids Fm.

Hony

Steinbruch Schmidt

i"" '" I

Carbonate

Figure 12: Lithostratigraphic comparison of Long Rapids Fm. type section and Hony (Belgium), Sinsin (Belgium). and Steinbruch Schmidt (Germany) F/F boundary

sections. Hony. Sinsin and Steinbruch Schmidt columns modified from Sandberg et al., (1988)

Hony Sinsin

\

Figure 13: Map of the Late Devonian (Famennian) palaeogeography and location of selected F/F sections. (after Scotese and McKerrow, 1990). Used with permission.

41

as a result of submarine scour or subaerial exposure caused by regressive seas

(however, see Girard et al. Il9971 for a differing opinion). Hypotheses on immediate

and ultimate causes for the FIF extinction will be discussed in more detail below.

Upperrnost Frasnian carbonate beds from the Sessacker trench near Oberscheld,

Gemany are similar to those of the Long Rapids Formation type section. Both

sections show a chaotic wackestone texture with dark organic staining and fossil

fragments, capped by a layer of thinly laminated mudstone (Schindler at al., 1998).

(Figure 14).

The Sessacker trench section is the only section in Europe where the FIF boundary

does not coincide with the top of Upper Kellwasser Limestone. This is similar to the

situation in the Long Rapids Formation type section. where the boundary occurs

within the first few cm of the black shale unit 24, about 10-12 cm above the top of

the upper Kellwasser-like carbonate unit 22 (Figs. 4, 5 and 6). It should be noted,

however, that many boundary sections (e.g. Figure 12) contain shale and mud

layers within and above the uppermost Frasnian carbonate beds, beds that

Upper Kellwasser strata from Ihe Sessacker trench qheinisches Schiefergebirge, Germany) Schindler et al., 1998, PI. 3, fig. 8).

Long Rapids Formation type section, Unit 20.

Figure 14: Cornparison of Long Rapids Formation type section and Sessacker trench carbonate strata just below the FIF boundary, showing similarities in organic staining & thinly laminated micritic caps

43

apparently have not been sampled for conodonts (Steinbruch Schmidt in Gennany,

Hony and Sinsin in Belgium, Devil's Gate in Nevada; see Sandberg et ai., 1988).

Since, as this study shows, shale/mud lithologies often produce significant conodont

yields, it is puuling why these units were not tested. Although Sandberg et al.

(1 988) called the 5 cm dark carbonaceous shale between the top of the Frasnian

Iimestone and the overlying Famennian strata in Steinbruch Schmidt the "extinction

layef, no biofogical or geochemical evidence was provided. Over (1 997) sarnpled

some shales in his analysis of the F/F boundary in western New York; however, he

collected mainly from shale surfaces, so yields were limited and possibly unreliable.

Geochemistry

Extensive geochemical testing was done on a cm to decimeter basis in the boundary

strata, from the mud unit (sample 19) below unit 24 (samples 20-26) into the

Famennian. Seven parameten were investigated in detail: whole rock and trace

element composition, iridium content and isotpe ratios for carbon, oxygen, nitrogen

and sulphur.

Trace elements

A general preliminary analysis was done of the carbonate beds in the whole section

to gel an overview of the whole rock and trace element composition of the Long

Rapids Formation type section (Table 1). Later, more detailed whole rock and trace

element samples were taken of the F/F boundary area on a much more detailed

scale (Tables 4-6), testing for any geochemical anomalies in the boundary beds

which might enhance our understanding of what caused the biological extinctions.

lnductively coupled plasma emission spectometry was carried out by Activation

Laboratories of Ancaster, Ontario. Most of the results were as expected: the major

carbonate lithology is a dolomitic limestone with a high clay content. Elevated levels

of V, Zr and Ba were found in the carbonates below the F/F boundary but this is not

surprising since these elements concentrate preferentially in shales over carbonates

(Turekian and Wedepohl, 1961) and the Long Rapids Formation type section

carbonates are quite argillaceous (between 15% and 37% Si02 content, see Table

1). Some of these elements, however, are thought to be indicative of anoxia.

lncreased levels of vanadium, for example, have been interpreted as an indicator of

anoxic sediments at three FIF boundary sections in Utah (Bratton et ai., 1999)

45

where, as in the Long Rapids Formation type section, the increase precedes the

boundary interval. Boundary strata shale beds also show uranium content that is two

to three times richer than a "normal" shale (Turekian and Wedepohl, 196 1) and

thought to be an indicator of anoxic sediments (Calvert, 1976). The chalcophile

elements sulphur, antimony and arsenic, which in their sulphide forrn are indicative

of a reducing environment (Krauskopf, 1979), increase sharply at the lag layer (base

of unit 24, sample 20, where pyrite is observable) and remain high throughout

(Tables 5, 6). As will be discussed in some detail below, anoxic conditions are also

demonstrated by carbon isotope ratios. Other anomalies present include increased

levels of Ba which have been interpreted as an indicator of hydrothermal activity

caused by increased island arc vulcanism and subduction at the end of the Frasnian

(Racki, 1998a); however, the increased levels of Ba in the Long Rapids Formation

type section are present only in the carbonate strata and may be due to their high

clay content, as outlined above. lncreased Ni, about Nice the shale average, is also

present (Table 6) , but the significance, if any, is unknown.

Iridium

Using Neutron Activation Analysis (NAA), Iridium (Ir) was also tested for, as an

indicator of a bolide impact (Alvarez et al., 1980). NAA bombards the sample with

neutrons in a nuclear reactor to form new radionuclides that decay and produce

gamma particles with characteristic energies indicative of their source elements,

measurable with a scintillation counter.

No significant Ir anomaly was found at the boundary; these findings are consistent

with other F/F sections world wide (Goodfellow et al., 1988; Claeys et al., 1996; Over

et al., 1997; Hallam & Wignalt, 1997). The only Ir anomaly ever reported for the

FrasnianIFamennian boundary is in Australia where the anomaly is probably of

biogenic origin, and in any case, was later found not to correspond with the

boundary (McGhee, 1996; Girard et al., 1997) (Table 7). For cornparison purposes

the Danish Mesozoic section at Stevns Klint sampled by Alvarez et al. (1 980)

showed an iridium anomaly of 41.6 ppb for the CretaceoudTertiary boundary;

another Cretaceouflertiary boundary section in the Red Deer Valley, Alberta

contains iridium concentration of 3.36 ppb (Lerbekmo and St. Louis. 1985). Most

47

results from the Long Rapids Formation type section are well under 1 ppb, aithough

a green mud layer (sample 15) -90 cm below the boundary measured 4 ppb. This is

a significant amount. 3-12 times background, and 4 times crustal average of 1 ppb

(Klein and Hurlbut, 1977); however in the absence of additional data indicative of an

impact event, e.g., microtektites, one cannot demonstrate an extraterrestrial origin

for the iridium. Ir anomalies may also be the result of volcanic/hydrotherma1. low

temperature depositional processes (that are enhanced by anoxic conditions and

accumulations of organic matter), biological and post depositional causes

(Sawlowics, 1993; Sharpton and Ward, 1990).

Carbon occurs in three isotopes, 12C (98.89% of natural carbon), '3C (1.1 1%) and 14C

(decays with a 5570 year half-life and because of decay is not present in Palaeozoic

rocks). Photoautotrophic organisms prefer the lighter isotope in photosynthesis as it

is easier to assimilate. Thus an enrichment in 13C might indicate the increased

activity of phytoplankton actively removing the lighter isotope. 13C enrichment can

also be interpreted to indicate mass mortality where large amounts of organic matter

48

are deposited in an anoxic sedirnentary environment and the organically fixed

carbon is not released back into the environment, because there is no oxidization

(McGhee, 1996). If the 6% is negative and the amount of 13C decreases, one might

Say that it is the result of a temporary reduction of surface water productivity and

biomass associated with an extinction (Wang et al., 1996). There are also two tests

for 13C, one for the organic component of the rock and one for the inorganic

carbonate component of the rock. Most researchers choose one or the other (but

see Joachirnski, 1997 for a comparison of the two). In some sections there is a

positive excursion (e.g., Steinbruch Schmidt, Gennany; Coumiac, France;

Laojiangchong, south China; Medicine Lake, Alberta) aild in some areas there is a

negative change (Cinquefoil Mountain, Alberta; Luoxiu, south China) (Wang et al.,

1991 ; Joachimski and Buggisch, 1993; 1996; Zheng et al., 1993; Hou et al., 1996).

Each researcher has interpreted the increase or decrease in I3C according to hisher

own preferences.

Both organic and inorganic '2C/13C ratios were measured at the University of

Waterloor's Environmental Isotope Laboratory using mass spectometry. a process

that separates the different isotopes by vaporization, accelerating them through a

strong magnetic field, and then measuring their different electrical potentials by

elect rometry.

The results are shown in Figure 15. In the lag layer underlying the FIF boundary

there is a significant increase of organic and carbonate 13C of between 2 per mille

(organic) and 5 per mille (carbonate) that is maintained (organic) or increases

(carbonate) through the boundary and drops afteiwards, in most of the remaining

samples. This compares with similar increases in three German sections reported by

Joachimski and Buggisch (1 993): Steinbruch Schmidt in the Rheinische

Schiefergebrige, +3.0 per mille; Steinbruch Benner in the Rheinische

Schiefergebrige.. +3.3 per mille and Vogelsberg in Thuringia, +3.9 per mille.

The total organic carbon (TOC), increases sharply at the basal lag layer (sample

20), and reaches a peak of over 10 per cent in the FIF boundary area (sample 20-

6). Compare this to results of Bezys and Risk (1990) for the Long Rapids Formation

type section that show TOC ranging between 0.75 per cent and 6.27 per cent, with a

mean value for the black shales of 4.6 per cent. The correlative Kettle Point

Formation of southem Ontario ranges between approx. 2-15 per cent TOC over the

G r o w n Mudslone Ootoetono

Figure 15: Percentage composition carbon and carbon isotope ratios in the FIF boundary strata, Long Rapids Fm. type section.

5 1

entire range of the formation with an average around 7 per cent (Armstrong et al.,

1988; Russell, 1985). Clearly the TOC and carbon isotope spikes indicates a

sudden removal and burial of a great deal of organic matter into an anoxic basin,

that preserved the organic matter and the 12C within it, thus elevating I3C

propoitions. Whether the positive 13C excursion is due to a phytoplankton bloorn or a

mass dying, or both, is unknown. A causal Iink between the former and latter

phenornena has been explained (Murphy et al., 2000) by eutrophication leading to

high surface-water productivity, loss of water clarity and the development of benthic

anoxia, as respiratory demands exceed 4 supply.

Nit roaen

Along with '2C/13C ratios 14NPN ratios were also measured as part of the

Environmental Isotope Laboratory's analytical package. This is the f irst time nitrogen

isotope ratios have been tested for at the F/F boundary, although they have been

studied at the Cretaceousflertiary boundary (e.g. Gilmour et al., 1990) and in other

parts of the Phanerozoic.

52

Since plankton also contains nitrogen in the fom of proteins and as in carbon the

lighter isotope is preferentially utilized by the organism, one would have expected to

witness a positive alSN change at the F/F boundary. This is in fact what is reported at

the K/T boundary in Woodside Creek, New Zealand (Gilmour et al., 1990). However,

results at the Long Rapids Formation type section show a positive 14N/15N ratio only

until the start of the hardgroundAag layer surface (base of unit 24, sample 20), where

the ratio suddenly becomes negative (Figure 16). This puzzle may be explained by

the hypothesis of Wang et al. (1 996) that surface water productivity and biomass

decline during an extinction event. If 14N is not being taken up by organisms, 15N

quantities decrease proportionately, thus driving the ratio negative. This scenario

would assume of course that 14N is not locked up in an anoxic sedimentary basin,

that is in fact the case as denitrification takes place in stratified anaerobic water

bodies (Hoefs, 1997:43), whereas decarbonization does not.

O x y m

Figure 16 also displays the results of oxygen isotope testing: a major positive

excursion in d''O of over 3.0 per mille occurred at the boundary, followed by a large

negative move in the other direction, starting at sample 23 of over 10 per mille. The

Black shcrle Green Mudslone DoIoetone

Figure 16: Oxygen and nitrogen isotope ratios in the F/F boundary strata, Long Rapids Fm. type section.

54

ratio of the stable oxygen isotopes, 1 8 0 and 160 is used as a method for estimating

past ocean temperatures, as the proportion of 1 8 0 increases as temperature falls.

When water freezes the lighter 160 is preferentially frozen out in the ice, leaving

behind increased amounts of the heavier isotope in manne waters (McGhee, 1996).

Because of very small amounts of Ca0 in al1 the shale and mud samples at the Long

Rapids Formation type section, results must be treated with some caution, although

they are not inconsistent with reports from other F/F sections. j 8 0 values from strata

at Steinbruch Schmidt shows a positive a180 shift at the boundary although there is

only a small negative shift afterwards (McGhee, 1996); F/F strata of the Canning

Basin in Western Australia show a similar positive shift, followed by a steady

negative decline, perhaps indicating a sudden temperature drop followed by a

waming trend (Goodfellow et al., 1988); at Coumiac the dT8C values are high until 10

cm above the boundary and remain low until60 cm above, where they return to

normal (Goodfellow et al., 1988) - researchen believe this indicates a warming

trend after the mass extinction - although there is no indication of a temperature

drop at the boundary. In Luoxiu, south China researchers report a sudden +at80 shift

that suggests a short lived decrease in temperature (Yan-Zheng et ab, 1993). The

overall isotopic data, including the results from the Long Rapids Formation type

55

section, supporl the hypothesis that there was a sharp drop in temperature at the

boundary, followed by a longer warrning trend thereafter. The temperature drop was

probably caused by the enhanced burial of organic carbon that had a significant

effect on CO, and 4 concentrations in the atmosphere; lower CO2 causes global

cooling and may even lead to a worldwide regression if there is a buildup of the polar

ice caps (Joachimski and Buggisch, 1993).

Suiphur

Sulphur 8% data can be used to provide evidence for reducing water conditions at

the F/F boundary (Wang et al., 1996). Sulphate reducing bacteria, that thrive in

anoxic waters, prefer lighter isotopes, producing lighter isotope sulphides and

leaving residual heavy isotope sulphates. High sulphide production andor high

pyrite buriat (also a light sulphide) enrich sea water in the heavier isotope. "S. so

that sedimentary sulphide that was formed later through bacterial reduction would

exhibit higher 2% values (Wang et al., 1996; McGhee, 1996).

Sulphur 3% values at the Long Rapids Formation type section are ambiguous.

There is a very significant (almost 10 per mille) negative spike in the green mud level

just below the boundary that peaks at the basal lag layer, where the percentage of

sulphur also jumps to over 5 per cent. There is then a small, approximately 2 per

mille positive spike at the boundary and the figures stay in this range for the

remaining samples, except for two positive excursions at the green mud layers

(samples 22 and 24) that may be lithologically dependent (i.e., increased

oxygenation resulting in increased sulphates) (Figure 17).

In two sections in Alberta measured for % P2S ratios, a positive spike was observed

at the F/F boundary (Wang et al., 1996). There was atso a large negative spike that

occurs just below the boundary (which also occurs at the Long Rapids Formation

type section) and probably represents the initial sulphide production at the onset of

anoxia, where sulphides would be enriched in the lighter isotope until the lighter

isotope was depleted and the heavier isotope preferentially utilized. The large

amount of sulphur present at the F/F boundary is probably the result of volcano-

hydrothermal activity, which may or may not have been caused by a bolide impact

(Racki, 1 998a).

Black s h a l w Green M u d s t o n w Dolostone

Duration of the F/F Event

The timing of the carbon, oxygen, nitrogen and sulphur isotopic ratio changes show

a pattern which sheds some light on the duration of the FrasniadFamennian

extinction event. Changes begin in the mudstone horizon below the boundary

(sample 19) which corresponds to the topmost part of the Late Palmatolepis rhenana

Zone and continue through the discontinuity surface (sample 20-1) and other

Palmatolepis linguiformis Zone samples (20-2 through 20-6). Maximum 6 values

occur either in samples 20-2 (+6 13c organic), sample 20-4 (+6 ' 3~ carbonate,

+ 6 %, and - 6 %) or in sample 21 -1 (-6 '=N), the base or first cm of which (see

page 13) corresponds with the FrasniadFramennian boundary and beginning of the

Early Palmatolepis triangularis Zone. After the maximum is reached 6 values remain

relatively high, ignoring positive spikes in the suphur and nitrogen isotope ratios in

samples 22 and 24 which may correlate with the change of lithology from shale to

mudstone. Negative 6 "0 values peak in sample 23 which, as stated above, is

consistent with a warming trend after the F/F boundary. Although the extent of the

discontinuity between sample 19 and 20 is unknown, there appears to be a relatively

continuous change in isotopic ratios between the Late Palmatolepis rhenana Zone,

the Palmatolepis linguiformis Zone and Early Palmatolepis triangularis Zone,

suggesting that the F/F extinction took place gradually over the course of some tens

of thousands of years or more (see page 23). The greatest change seerns to have

taken place in the latter part of the Palmatolepis linguiformis Zone.

Discussion

Geology is al1 about time and "we derive time frorn boundaries" (McLaren, 1970).

Since McLaren's presidential address we have leamed a lot about the

FrasniadFamennian extinction that took place 364 million years ago (Sandberg and

Ziegler, 1996). There is now general agreement that the immediate cause of the

extinction was oceanic oxygen depletion, exacerbated by oceanic overtum, flooding

shallow epicontinental seas and killing benthic organisms (Goodfellow et al., 1988;

Sandberg et al., 1988; Schindler, 1990; Geldsetzer et al., 1993; Racki, 1998a;

Schulke, 1998; inter alia). The results from the Long Rapids Formation type section

are consistent with this hypothesis. There is also strong sedimentological and biotic

evidence for a sharp marine regression at. or just before, the boundary (Sandberg et

al., 1 988; Geldsetzer et al., 1 993; Muchez et al., 1 996; this study). lncreased

60

icnodids and the presence of disconformity surfaces (Trout River, N.W.T; possibly

Coumiac, France; the top of unit 20 (sample 16) and the base of unit 24 (sample 20)

at the Long Rapids Formation type section) suggest that a regression exposed the

carbonate strata to subaerial or subaqueous erosion and was immediately followed

by a marine transgression just before the F/F boundary. At the Long Rapids

Formation type section the transgression is recorded in the erosion surface at the

base of unit 24, which may represent a ravinement or maximum flooding surface:

this is then followed by an extensive -25 metre black shale sequence, -1 Sm of

which is exposed in the type section on the Abitibi River and an additional -1 0m

logged in the Onakawana 6 core (Bezys and Risk, 1990). Increasing palmatolepid

vs. polygnathid generic percentages after the boundary (Figure 11) are another

indicator of deepending waters (Sandberg, 1976). While the entire Long Rapids

Formation was deposited in relatively deep waters. consistent with a mainly pelagic

palmatolepid/potygnathid biofacies, below the F/F boundary the strata of mainly

mudstone altemating with dolomitic carbonate appear to represent shallower water

conditions (Brett and Baird, 1985) than the shale beds at and above the boundary,

which may represent the beginning of a late Frasnian, early Famennian

transgression after the shallowing just before the F E

6 1

While the F/F boundary extinctions are traditionally associated with a regression

which penisted into the early Famennian (Sandberg et al., 1988; Joachirnski and

Buggisch, 1993; Muchez et al, 1996; Morrow, 2000) data from this study suggests

that the regression took place just before the boundary and the boundary itself

marks the beginning of a transgressive episode, recorded in the anoxic black shales.

The continued presence of icriodids in the beginning of the black shale sequence at

the Long Rapids Formation type section (samples 21 -26) suggests that the

transgression began initially in a shallower water setting. The link between

transgressions, the spread of anoxic bottorn waters and marine extinctions has been

particulariy well documented throughout the Phanerozoic by Hallam and Wignall

(1 999) who questioned whether the WF extinction was caused by a regression. as

has been traditionally assurned since the time of Newell (1 967). Over (1 997) also

located the F/F boundary in New York within a black shale transgressive sequence;

had the black shale strata in sorne the classic European sections been examined for

conodonts (page 29, above), the F/F boundary location might have shifted from the

limestone to the shale. potentially altering sequence stratigraphie interpretations.

The ultimate cause of the anoxia is controversial. One group of geologists

(Sandberg et ab, 1988; Geldsetzer et al., 1996) have maintained that a bolide impact

at the F/F boundary initiated "drastic sedimentary events, including major storms,

dumping, debris flows and the formation of tsunami deposits" (Geldsetzer et al.,

1996: 190). Sandberg et al. (1 988) hypothesized that the event was caused by a

"variety of interrelated factors" including "rapid rise and fall of sea-level, causing

corresponding changes in the oxygen-minimum level, stratification and de-

stratification of the water column and reversal of current directions producing

oceanic turnover", al1 associated with the "theorized" (Sandberg et al., 1988:296)

impact of a large bolide. Tsunamis are also interpreted to have resulted from the

collapse of carbonate platforms at the lowest point of the regression, represented in

the stratigraphical record by a debris flow limestone congolomerate in Devils Gate,

Nevada (Sandberg et ai., 1988:288).

The bolide impact theory is appealing as it provides a simple 'instant' answer to a

veiy complex problern; however, an iridium anomaly expected with a bolide impact is

not present in the Long Rapids Formation type section. The only F/F section with an

Ir anomaly occurs in south China (Wang et al., 1991) and is very slight (.23 ppb),

63

over two orders of magnitude less than the Stevns Klint, Denmark, Ir high. The Long

Rapids Formation type section shows a significant anomaly of 4 ppb in unit 19

(sample 1 S), well below the boundary that, as was discussed, may or rnay not be

attributable to an impact. The stratotype section at Coumiac was investigated for Ir

anomalies by Girard et al. (1 997), as was the Hony section in Belgium (Ciaeys et al..

1996); both iacked iridium anomalies; however, at Hony a microtektite layer was

found at, or close to an uncertain F/F boundary. Nickel-silicate spherules have also

been reported close to the FIF boundary from south China (Wang and Bai, 1988; Bai

et al., 1994), suggesting that cometary impacts may have been involved in the

overall FIF perturbations.

The sedimentological evidence presented by Sandberg et al. (1 988) of storm

deposits in Steinbruch Schmidt, Hony and Sinsin and tsunami breccia at Devils

Gate, just above the boundary, are equivocal. Others have suggested that the

phenomeoon is due to in-situ brecciation caused by earthquakes, i.e. a seismite

(Schindler. 1990b; Pans et al., 1996; Schindler et al., 1998). Brecciation was not

observed in the Long Rapids Formation type section and sedimentation was

apparently continous and srnooth across the F/F boundary. There is, however,

64

ample evidence of tectonic activity (extensive faulting and folding) within the section;

this cannot unfortunately be tied to boundary events as sorne researchers have

done (Racki, 1998a). Ultramafic intrusives have been found at Sextant and Coral

Rapids on the Abitibi River south of the Long Rapids Formation type section, but

their relationship to the surrounding sedimentary rocks only indicates that the

perturbations were post-Eifelian (Sanford and Norris, 197581 ).

In two recent studies, Racki (1998a, b) suggested that while bolide events near but

not at the F/F boundary likely participated in the F/F destabilization, the ultimate

cause was a tangled combination of nutrient poisoning and mostly related anoxia,

rapid tectonic subsidence, and profound sea-level and climatic variations" resulting

from a major rifting event related to superplume activity. A similar conclusion was

reached earlier by Schindler (1 WOa, b) who concluded that multicausal, largely

earth-born processes were responsible for the extinction. Schindler hypothesized

that tectonic rnovements. like narrowing of the Palaeotethys Ocean, caused eustatic

changes and altered prevailing currents. This together with the onset of southem

hemisphere glaciation, lowered temperatures, changed the water chemistry and

stratified the water column, eventually leading to oceanic inversion where anoxic

65

bottorn waters suddenly invade the photic zone. In al1 these scenarios, the precise

triggering mechanism for the oceanic overtum, whether bolide impact, increased

rifting and plate subsidence, or hydrothennal or volcanic activity, is unclear. Another

possibility is that there was no oceanic overturn at ait, simply an upward movement

of the pycnocline as proposed by Russell (1 993) for the Kettle Point Formation of

southwestern Ontario. Hallam and Wignall (1999) link the anoxia to high amplitude

regressive-transgressive couplets. Another group of geologists (Algeo et al., 1995;

Algeo and Scheckfer, 1998) posit a direct connection between arborescence (tree

stature) and the rise of the seed bearing land plants, development of soils,

increased nutrient discharge, and eutrophication causing phytoplanktonic blooms,

muddying surface waters and creating anoxia due to the respiration of sinking

organic material. While the results are generally clear, the causes are less so, even

though they are al1 probably closely interrelated, interdependent and cornplex.

Summarv

It has often been obsewed that the geological "record" is more gap than record

(Ager. 1 993; Miall, 1 997). Even though precise biostratigraphic and geochemical

control allows us to identify the Frasnian-Famennian boundary in the Long Rapids

Formation type section (northem Ontario. Canada), there are gaps present. Parts of

the Late Palmatolepis rhenana Zone and the Palmatolepis linguiformis Zone are

missing. but fottunately, the critical F/F interval is present in a continuous black

shale sequence. Although there is an indium anomaly -90 cm below the boundary,

there is no evidence there, or at the F/F boundary for a sudden extraterrestrial

impact. The change across the boundary, frorn the basal discontinuity surface of unit

24 (sample 20) to the beginning of the Lower triangolaris Zone is smooth and

continuous. Although there was mass mortality at this horizon there is no single

bedding plane where the Frasnian conodonts die out and the Famennian appear -

the dying was gradua1 and continual, although over a relatively tiny 'instant' of

geological time - thousands to tens of thousands of years in duration.

Since the original discovery of iridium anomalies by Alvarez et al. (1 980),

catastrophe theory has had a major renaissance. In the public's mind, dinosaurs

67

were killed by asteroid impact that precipitated a 'nuclear winter'. Although there is

little, if any, evidence for this in the fossil record - see, for example, the Geological

Association of Canada's 1999 Symposium on Global Mass Extinctions and Impacts,

where not a single paper presented gave evidence of a sudden impact causing any

of the Phanerozoic extinction events - some geologists still contend that the

immediate and ultimate cause of the extinction at the end of the Cretaceous was

"virtually proven" (Gould. 1994) to be an asteroid impact. Clearly there are bedding

planes that contains significant iridium anomalies and there was an asteroid impact,

but the fossil record shows that dinosaurs and a host of other organisms began to

die out out millions of years before the impact event in a series of stepwise

extinctions (Keller and Barrera. 1990; Tassy, 1993). If the impact event had an

effect. it was to accelerate the extinctions that were already taking place.

People prefer simple answers and to assert that life is contingent on random events

has a certain appeal in a time in human history when teleological thinking is in

disrepute. But while the Cretaceous-Tertiaty boundary events are capable of diverse

interpretation, those of the FrasniadFamennian are much less so. Although there

may have been an impact(s) near the boundary, the extinction was not caused by

68

an extraterrestrial impact, but by a complex web of uniformitarian, earth-born factors.

The Long Rapids Formation type section records these events faithfully - an anoxic

epicontinental basin under severe stress from sea Jevel changes, change in water

chemistry and climate, and a struggling biota; some species died out and some

survived. This is the very kind of environment that accelerates evolution and creates

new species better adapted to survive these rapidly changing conditions (Eldredge

and Gould, 1 972). In the Late Devonian , Palmatolepis praetriangularis evolved out

of the common gene pool shared by Palmatolepis hassi/Pa. subrectaPa. rotunda

(al1 of which were under stress and subsequently died out), to survive as the sole

ancestor of al1 palmatolepids in the Famennian.

What particular adaptations gave Palmatolepis praetriangularis an evolutionary

edge? Abundant mature specimens of reduced size suggest that one important

advantage the species rnay have had is reproductive prolificacy and progenesis, the

ability to mature faster and reach sexual maturity at a smaller size. Palmatolepis

praetriangularis also had a generalized morphology sharing different features of its

ancestor stock, Palmatolepis hassüPa. subrectaPa. rotunda that may have made it

more adaptable to changing conditions. If lack of oxygen was the cause of the mass

69

dying, another possibility is that Palmatolepis praetriangularis may have developed a

respiratory system that absorbed and utilized what little oxygen there was available

more eff ectivel y. Palmatolepis praet~angularis evolved in to Palmatolepis

triangularis, one of the most prolific and successful species of the Early Famennian.

The only difference between the two species is the inflection of the upper side of the

Pa element posterior platforni; in Palmatolepis praetriangularis it is level or

downbent, in Palrnatolepis triangularis it rises. Was this a selective advantage in

feeding, providing a better fit between opposing Pa elements, for more efficient

crushing (Briggs et al., 1983; Pumell and von Bitter, 1992; Purnell, 1995) and

utilization of what little food there was available, after the mass mortality of phyto-

and zoopfankton? Or was this just an incidental by-product of some more important

evolutionary change in the soft tissue of the conodont animal? Until we find

Devonian soft bodied conodont remains, we cannot know.

The mean survival time of conodont genera from the Cambrian to Triassic is about

30 million years (Sweet, 1988). Palmatolepis survived for only -14 million years,

from the lower Frasnian Palmatolepis transitans Zone into the lower part of the

Siphonodella sulcata Zone in the Dinantian (Ziegler and Sandberg, 1984; Sandberg

70

and Ziegler, 1996). The Long Rapids Formation type section records a major crisis

in this generic history where some 18 palmatolepid species died out, to be replaced

by only one descendant species, a dramatic snapshot of the evolutionary process

during one of the most important extinction events in earth's history. Palmatolepis

praetrfangularis flourished and became the progenitor of dozens of Famennian

species, before the genus becarne extinct just above the Devonian/Carboniferous

boundary (Sandberg et al., 1 978).

Svstematic Palaeontoloay

Order Ozarkodinida Dzi k, 1 976

Family Palmatolepidae Sweet, 1988

Genus Palmatolepis Ufrich and Bassler, 1926

Palmatolepis delica tula delica tula B ranson and Mehl , 1 934

PI. 1, figs. 1, 2

Palmatolepis delicatula delicatula Branson and Mehl, 1934, p. 237. pl. 18, figs. 4,

1 O.

Palmatolepis delicatula delicatula, Ziegler and Sandberg, 1990, p. 67, pl. 17, figs. 1 -

3.

Palmatolepis delicatula delicatula, Morrow, 2000, p. 53, pl. 3, fig. 3

Diagnosis: A very wide triangular Pa element outer lobe, with the posterior and

anterior parts more or less equal. Similar to Palmatolepis jamieae, but with a

straighter outline. This Pb element, recovered from sample 24, is sufficiently different

from the Palmatolepis triangularis Pb element to belong to its related, descendant

species, Palmatolepis delicatula delicatula. Much less flexure in the main bar and

72

larger, subequal anterior teeth distinguish this Pb element from Palmatolepis

trkngula ris.

Material: 976 Pa elements. 1 Pb element

Distribution: Samples 21 -25 in the Long Rapids Formation type section.

Palmatolepis ederi Ziegler and Sandberg, 1 990

PI. 1 Fig. 3

Palmatolepis ederi Ziegler and Sandberg, IWO, pp. 62-63, pl. 9, figs. 1-7; p. 101 , pl.

10, figs. 6-1 0.

Palmatolepis ederi, Morrow, 2000, p. 49, pl. 1 , fig . 1 0.

Diagnosis: Ve ry sim ilar to Palmatolepis linguiformis, Palmatolepis ederi is

distinguishable from the former species by a posterior carina of the Pa element that

does not reach the posterior tip of the platfonn, with smaller posterior carina nodes

than anterior carina nodes and a longer range. Also the parapet area is less

expanded and does not bulge outward, and the platform is less sigmoidal in shape

than Palmatolepis linguiformis.

73

Remarks: The only mature specimens of this species found were in the lower part of

unit 24A (sample 20), Le. the linguiformis Zone.

Material: 13 Pa elements, but only 7 mature specimens.

Distribution: Restricted to sample 20 of the Long Rapids Formation type section,

although some juvenile specimens may have occurred below.

Palmatolepis foliacea Youngquist. 1945

PI. 1, figs. 4, 5

Palmatolepis foliaceus Youngquist, 1 945, pp. 364-365, pl. 56, figs. 1 1 -1 2.

Palmatolepis foliacea, Ziegler and Sandberg. 1990, pp. 49-50, pl. 5, figs. 1-8,11-12.

Palmatolepis foliacea, Norris et ab, 1 992, p. 74, pl. 1 3, fig. 1 3.

Palmatolepis foliacea, Klapper and Foster, 1993, p. 8, fig. 6.1-6.9.

Diagnosis: a species with a non-lobed, ovoid, nodose platfom and a wrinkly ovoid

border.

Remarks: a well established, non-controversial species that became extinct at the

top of the Late rhenana Zone.

74

Material: 193 mature Pa elements, al1 from the Williams Island Formation type

section type section. The specirnen illlustrated by Noms et al. (1 992) was from the

Long Rapids Formation type section. This study found no specimens of Palmatolepis

foliacea in the Long Rapids Formation type section.

Distribution: Williams lsland Formation type section samples 1-6.

Palmatolepis gigas Miller and Youngquist, 1947

PI. 1, fig. 6

Palmatolepis gigas Miller and Youngquist, 1947 p. 51 2-51 3, pl. 75, fig. 1.

Palmatolepis gigas gigas, Ziegler and Sandberg, 1990, p. 54. pl. 7, figs. 1-6; p. 97,

pl. 8, figs. 5-7.

Palmatolepis gigas gigas, Monow, 2000, p. 49, pl. 1, fig. 6.

Diagnosis: a straight canna, a long, pointed outer lobe, and a long rostrum

characterize this species.

Remarks: this species extends into the late linguiformis Zone (Ziegler and

Sandberg. 1990). but at the Long Rapids Formation type section, does not go

beyond unit 21 (sample 17).

Material: 6 Pa elements.

Distribution: Samples 2, 5, 6, Williams Island Formation type section and samples

10, 17, Long Rapids Formation type section.

Palmatolepis hassi Müller and Müller, 1957

PI. 1, figs. 7, 8, 9

Palmatolepis (Mantico/epis) hassi Miiller and Müller, 1957, pp. 1102-1 103, pl. 139,

fig. 2; pl. 140, figs. 2-4.

Palmatolepis hassi, Ziegler and Sandberg, 1 990, pp. 55-56, pl. 2. figs. 2-9; p. 1 05,

pl. 12, figs. 10-1 1

Palmatolepis hassi, Klapper and Lane, 1 993, p. 22, figs. 1 5.1 - 1 5.9 (Pa element); p.

27, figs. 18.12; 19.1 6-1 9.18 (Pb elernent).

Palmatolepis hassi, Schindfer etal., 1998. p. 260, pl. 5, fig. 31.

Diagnosis: The Pa element of Palmatolepis hassi has a general rotund shape, but

with a conspicuous upward and outward bulge of the outer anterior platform and a

strongly convex outer posterior lobe. The Pb element has a moderately arched

platform with higher anterior denticles than posterior, and a wide inner platform up to

two-thirds the overall length and narrow outer platform.

76

Remarks: a non-controversial species that ranges from close to the base of the Long

Rapids Formation type section into the Palmatolepis linguifomis Zone.

Material: 62 Pa elements. 48 Pb elements

Distribution: Samples 8, 9, 12-20 in the Long Rapids Formation type section.

Palmatolepis jamieae Ziegler and Sandberg, 1 990

PI. 1 fig. 10

Palmatolepis jamieae Ziegler and Sandberg, 1 990, pp. 50-5 1 , pl. 6, figs. 1 - 1 0; p.

103, pl. 1 1, figs. 4-6.

Diagnosis: A species with a large, trapezoid shaped very broad outer platform,

similar in shape to Palmatolepis delicatï.'a, but more irregular in outline.

Remarks: This is only the second reported occurrence of this species.

Material: 5 Pa elements.

Distribution: Samptes 19 and 20, Long Rapids Formation type section.

Palmatolepis juntianensis Han, 1 987

PI. 1, fig. 11

Palmatolepis juntianensis Han, 1 987, p. 1 86, pl. 1 , figs. 1 5- 1 6.

Palmatolepis juntianensis, Ziegler and Sandberg, 1990, p. 52, pl. 14, figs. 16-1 7.

Palmatolepis juntianensis, Morrow, 2000, p. 49, pl. 1. fig. 8.

Diagnosis: The Pa element platfonn of this species is reduced and the posterior part

bulges out close to the posterior tip, giving it a distinctive clublike appearance.

Remarùs: Pa. juntianensis has a range very similar to Palmatolepis linguifomis,

basically restricted to the area of the immediate boundary.

Material: 74 Pa elements.

Distribution: Samples 17, 19-21 of the Long Rapids Formation type section.

Palmatolepis linguiformis Müller , 1 956

PI. 1 fig. 12

Palmatolepis linguiformis Müller, 1956 pp. 24-25, pl. 7, figs. 1-7.

Palmatolepis linguiformis, Ziegler and Sandberg, 1 990, pp. 59-60. pl. 1 4, figs. 8-1 0.

Palmatolepis linguiformis, Schindler et al., 1998, p. 261, pl. 5, fig. 30.

Palmatolepis linguifomis, Morrow, 2000, p. 51, pl. 2, figs. 4-5.

78

Diagnosis: Very similar to Palmatolepis ederi, except the canna of the Pa element

extends al1 the way to the posterior tip and the curvature of the canna and the

platfonn is more pronounced.

Remarks: in contrast to most F/F boundaries, a significant number of the nominate

species (64) was found at the Long Rapids Formation type section.

Material: 64 Pa elements.

Distribution: Samples 20 and 21, Long Rapids Formation type section.

Palmatolepis minuta minuta Branson and Mehl, 1934

PI. 1. fig. 13

Palmatolepis minuta minuta Branson and Mehl, 1934, p. 236, plate 18, figs. 1,6,7.

Palmatolepis minuta minuta, Ziegler, 1977, p. 387, pl. 9, figs. 1-5.

Palamatolepis minuta minuta, Morrow, 2000, p. 51, pl. 2, fig. 8.

Diagnosis: similar to Palmatolepis protorhomboidea but with a much reduced outer

platforrn, though still trïangular in shape.

Remarks: Sandberg and Ziegler (1 990) reported that this species represents the

boundary between the Middle and Upper Palmatolepis triangularis Zone.

Material: 39 Pa elernents.

79

Distribution: Samples 23-25, 27, 28 of the Long Rapids Formation type section.

Palmatolepis plana Ziegler and Sandberg, 1990

PI. 1, fig. 15-1 9

Palmatolepis plana Ziegler and Sandberg, 1 990, p. 46, pl. 3, figs. 1 - 1 0.

Palmatolepis domanicensis, Klapper, 1 989, pl. 1 , figs. 1 , 2.

Palmatolepis plana, Morrow, 2000, p. 49, pl. 1, fig. 1.

Diagnosis: A species similar to Palmatolepis foliacea with the same stratigraphie

range, but possessing more of a developed outer lobe on the Pa element.

Material: 7 Pa element specimens.

Distribution: Williams Island Formation type section, samples 1, 4.

Palmatolepis praetriangularis Ziegler and Sandberg in Sandberg et al., 1988

PI. 1, figs. 15-1 9

Palmatolepis triangularis O element, v.d. Boogaard and Kuhry, 1979, p. 34, fig. 5.

Palmatolepis praetriangularis Ziegler and Sandberg in Sandberg et al., 1 988. pp.

298-299, pl. 1, figs. 1-4.

Palmatolepis praetriangularis, Qiang, 1989, p. 295, pl. 3, figs. 1 1 to 18.

Palmatolepis praetriangularis, Schindler, 1 990a, pl. 5, figs. 6A, B.

Palmatolepis praetriangularis, Ziegler and Sandberg, 1 990, p. 42, text-fig. 1 0.

Palmatolepis sp. A Noms et al., 1992, p. 75, pl. 12, figs. 5, 6.

Palmatolepis triangularis, Wang and Geldsetzer, 1995, p. 1830, pl. 1, figs. 8, 9.

Palmatolepispraetriangularis, Girard etal., 1997, p. 394, figs. 3.1, 3.2.

Palmatolepis praetriangularis, Schindler et al., 1998, p. 259, pl. 4, fig. 16.

Palmatolepis praetria~gularis, Renaud and Girard, 1 999, p. 20, fig. 1 . b.

Palmatolepis praetriangularis, Morrow, 2000, p. 51 , pl. 2, figs. 6, 7.

Diagnosis: A species with a distinctive triangular shaped Pa element similar to

Palmatolepis triangularis, but with a platform that is flat or descends gently

posteriorward from the central node. The Pb element of Palmatolepis

praetriangularis is indistinguishable from Palmatolepis triangularis, an arched

nothognathellid platform with the anterior denticles gradually increasing in size to the

flexure points. It differs from subrecta in having no platfom development on the

outer side and in the graduai increase in denticle sire.

8 1

Remarks: Palmatolepis praetnangularis has a wide range of morphological variation

consistent with its derivation from the Palmatolepis hassi/rotunda/subrecta gene

pool. Some samples are intermediate in rnorphology and close to a 'late form' of

Palmatolepis subrecta (Ziegler and Sandberg, 1990, pl. 16, figs. 1-6) except for a

more triangular, pointed outer lobe, a tip always more anterior that the central node

and a more sigrnoidal carina. Norris et al. (1 992) illustrated one of these elements

from the lower part of the Long Rapids Formation type section as "Palmatolepis sp.

A . The species has been controversial, with Klapper et al. (1 993) synonymizing

Palmatolepis praetriangularis wit h Palmatolepis triangularis; th is st udy , howeve r,

supports the existence of Palmatolepis praetriangularis as a separate and distinct

species. See text for full discussion.

Material: 1238 Pa elements (51 3 and 725 mature and juvenile specimens,

respect ively) .

Distribution: Williams Island Formation type section, samples 1-6; Long Rapids

Formation type section, samples 7-2 1.

82

Palmatolepis protorhomboidea Sand berg and Ziegler , 1 973

PI. 2, fig. 1

Palmatolepis delicatula protohomboidea Sandberg and Ziegler, 1 973. p. 1 03, pl. 1 ,

figs. 14-1 9.

Palmatolepis protorhomboidea, Ziegler and Sandberg, 1 990, p. 68, pl. 1 7, figs. 8-

11.

Diagnosis: Similar in shape to Palmatolepis delicatula delicatula but smaller and

with an anterior outer lobe which meets the platforni considerably below the anterior

tip.

Remarks: a species characteristic of the Early triangularis Zone.

Material: 163 Pa elements.

Distribution: Samples 22, 24. 25, 27 in the Long Rapids Formation type section.

Palmatolepis rhenana nasuta Müller , 1 956

PI. 2 fig. 2

Palrnatolepis (Manticolepis) nasuta Müller, 1 956, pp. 23-24, pl. 6, figs. 3 1 -35.

Palamtolepis rhenana Bischoff, 1 956, p. 1 29, pl. 8, figs. 26-28, 30; pl. 10, fig. 7

Palmatolepis rhenana, Orchard, 1988, p. 43, pl. 1, fig. 16.

Palmatolepis rhenana nasuta, Ziegler and Sandberg , 1 990. p. 57, pl. 1 2, f igs. 4-9; p.

1 1 1, pl. 15, figs. 2,4,5.

Palmatolepis rhenana nasuta, Wang and Geldsetzer, 1 995, p. 1 83 1, pl. 2, fig. 5.

Diagnosis: A species with a sigrnoidal carina and a long, thin outer lobe on its Pa

element.

Remarùs: More common than rhenana rhenana, Palmatolepis rhenana nasuta is

present from the Williams Island Formation type section to the Palmatolepis

linguifonnis Zone boundary shale of the Long Rapids Formation type section.

Material: 62 Pa elements.

Distribution: Williams Island Formation type section, samples 1, 2 4-6; Long Rapids

Formation type section, samples 13, 20.

Palmtolepis rhenana rhenana Bischoff, 1 956

PI. 2, fig. 3

Palamtolepis rhenana Bischoff, 1956, p. 129. pl. 8, figs. 26-28, 30; pl. 10. fig. 7.

Palamtolepis rhenana, Klapper, 1 989, p. 458, pl. 2, figs. 1 , 1 3

84

Palamtolepis rhenana thenana Ziegler and Sandberg, 1990, pp. 57-58, pl. 12, figs.

1 -3; p. 1 1 1, pl. 1 5, figs, 1,3, 6-7.

Palamtolepis rhenana, Klapper and Lane, 1 993, p. 24, fig. 16.1 ; figs. 17.3-1 0.

Palamtokpis rhenana rhenana, Morrow, 2000, p. 49, pl. 1, figs. 4-5

Diagnosis: an easily recognizable species, because of a long, thin, pointed outer

lobe on its Pa element- thinner and more pointed than Palmatolepis rhenana

nasuta.

Remarks: This is the index fossil for the start of the Late Palmatolepis rhenana Zone.

Some workers (e.g. Klapper and Lane, 1993) do not recognize this subspecies, only

naming it to the specific level.

Material: 3 Pa elements.

Distribution: Williams Island Formation type section, sample 4.

Palmatolepis rotunda, Ziegler and Sandberg, 1 990

PI. 2, figs. 4,5, 6

Palmatolepis canadensis Orchard, 1988, p. 44, pl. 2, figs. 15, 16, 23.

Palmatolepis bogartensis Klapper, 1989, p. 458, pl. 2, figs. 7-8.

Palmatolepis rotunda Ziegler and Sandberg, 1 990, p. 62, pl. 1 0, figs. 1 -5.

Palamatolepis bogartensis, Klapper and Foster, 1 993, pp. 1 8-1 9, fig. 13.4-1 6 (Pa

element), p. 28, fig. 19.1 -5 (Pb element).

Palmatolepis rotunda, Wang and Geldsetzer, 1995, p. 1831, pl. 2, figs. 1-3.

Palmatolepis rotunda. Morrow, 2000, p. 51, pl. 2, fig. 1 .

Diagnosis: a round circular platform shape with a round outer posterior lobe. The Pb

element is refatively flat (non-arched) with the cusp not much higher than the

anterior denticles and low posterior denticles. A wide inner platform.

Remarks: Although the specific name of this species may be a junior synonym of

Nothognathella bogartensis Stauffer, 1 938, plate 48, figure 30 (Klapper, 1 989), the

latter Pb element may be vicarious in a number of similar apparatuses.

Material: 334 Pa elements (1 61 mature specimens and 1 73 juveniles); 6 Pb

specimens

Distribution: Palmatolepis rotunda is a widespread species in the Long Rapids

Formation type section extending from the underlying Williams Island Formation type

section up to the F/F boundary (sample 1 to sample 20, except units 8 and 15 where

the species is absent).

Palmatolepis cf. Pa. semicha tovae

PI. 2, fig. 7

Rernarks: The strongly developed outer lobe is reminiscent of Palmatolepis

semichatovae; however this latter species does not range out of the Frasnian.

Material: one Pa element recovered from the Long Rapids Formation type section

sarnple 25, which is about 30 cm above the F/F boundary.

Palmatolepis subrecta Miller and Y oungquist, 1 947

PI. 2, figs. 8-10

Bryantodus winchelli Stauffer, 1938, p. 423, pl. 48, fig. 33

Palmatolepis subrecta Miller and Youngquist, 1947, p. 51 3. pl. 75, figs. 7-1 1

Palmatolepis subrecta, v. d. Boogaard and Khury, 1979, p. 31, fig. 1.

Palmatolepis subrecta, Orchard, 1 988, p. 43, pl. 1 , figs. 20,21,24.

Palmatolepis winchelli, Klapper, 1989, p. 458, pl. 2, fig. 5.

Palmatolepis subrecta, Ziegler and Sandberg, 1990, pp. 60-61, pl. 1 1, figs. 3, 7-1 2;

pl. 15, figs. 8-9; pl. 16, figs. 1-6.

Palmatolepis winchelli, Norris et al., 1992, p. 75, pl. 13, figs. 1, 4, 5 (Pa elements).

87

Palamatolepis winchelli, Pb element, Klapper and Foster. 1993, pp. 24,26,31, figs.

19.6-1 9.12.

Palmatolepis winchelli, Over, 1997, p. 172, figs. 6.6, 6.7.

Palmatolepis subrecta, Schindler et al., 1998, p. 259, pl. 5. figs. 27-29.

Palmatolepis subrecta, Morrow, 2000, p. 51, pl. 2, figs. 2-3.

Diagnosis: A species with an ovate to elongate Pa element with a relatively straight

carina and a pointed outer lobe whose tip is in line with the central node. The Pb

element has a moderate to strongly arched platfonn (30 - 70 degrees) with a high

cusp and anterior denticles higher than posterior. It has a well-developed platforni on

the inner side with a platform on the outer side confined generally to the posterior

part or just the centre. The denticles are fused and those of the anterior subequal.

Remarks: A well established species whose specific name is contentious. Although

the specific name of Bryantodus winchelli Stauffer, 1938, a Pb element, may have

priority, numerous authors (Ziegler and Sandberg, 1990; Schindler et al., 1998;

Morrow, 2000) have considered this and similar Pb elements to be vicarious, and

have continued to use the species name subrecta for this species. Pa subrecta

88

occurs throughout the Long Rapids Formation type section and survives until just

past the F/F boundary.

Material: 480 Pa elements (366 mature + 114 juvenile specimens) and 352 Pb

elements.

Distribution: Williams Island Formation type section, samples 1, 2,4; Long Rapids

Formation type section, samples 1 1, 15, 17-21.

Palma tolepis triangula ris San nem ann , 1 955

PI. 2, figs. 1 1-1 7

Palmatolepis triangularis Sannemann, 1955, pp. 327-328, pl. 24, fig. 3.

Palmatolepis triangularis O element, v.d. Boogaard and Kuhry, 1979, p. 34, fig. 5.

Palmatolepis triangularis, Orchard, 1988, p. 47, pl. 3, figs. 6, 10.

Palmatolepis canadensis, Orchard. 1988, p. 47, pl. 3, fig. 9.

Palmatolepis triangularis, Ziegler and Sandberg, 1990, pp. 64-65, pl. 14, figs. 1-5.

Palmatolepis triangularis, Over, 1997, p. 171, figs. 10.1-10.5.

Palmatolepis triangularis, Morrow, 2000, p. 51, pl. 2, fig. 9.

Diagnosis: The platform shape has quite a bit of variation to it, but al1 specimens

have a general triangular shape with the tip of the outer lobe higher than the central

89

node. The posterior platforni bends upwards, a feature characteristic of Famennian

species. The Pb element of Palmatolepis triangulans consists of an arched

nothognathellid platfom with the anterior denticles gradually increasing in size to the

flexure points. It differs from subrecta in having no platforni development on the

outer side and in the gradua1 increase in denticle size.

Rernarks: The F/F boundary is defined by the first "flood occurrence" (Klapper et al.,

1993) of Palmatolepis triangularis, which starts at sample 21. There are thousands

of specimens and they are easily distinguishable from Pa. praetriangularis, in that

the posterior tip clearly rises. and their fonn is more cornpletely triangulated.

Material: 2895 Pa elements. 202 Pb elements.

Distribution: sample 21 -25, 27, Long Rapids Formation type section.

Family Polygnathidae Bassler, 1925

Genus Ancyrodella Ulrich and Bassler, 1926

Ancyrodella bucûeyensis Stauff er, 1 938

PI. 3, fig. 1

Ancyrodella buckeyensis Stauffer, 1938, p. 41 8, pl. 52, figs. 17. 18, 23, 24.

Ancyrodella buckeyensis, Over, 1 997, p. 1 72, fig. 1 1 .1- 1 1 -9.

90

Diagnosis: A distinctive 'arrowhead' shape with straight to slightly cuived carina

extending well above the platform.

Remarks: Although most ancyrodellids were casualties of the F/F extinction event,

this species survived as far as unit 24E in the Famennian, about 30 cm above the

F/F boundary.

Material: 108 Pa elements.

Distribution: Samples 13-1 5, 17, 18, 20, 21, 23, 25 in the Long Rapids Formation

type section.

Ancyrodella curvata Branson and Mehl, 1934

PI. 3, fig.2

Ancyrodella cuwata Branson and Mehl, 1934, p. 241, pl. 19, figs. 6, 11.

Ancyrodella cuwata, Klapper, 1989, p. 457, pl. 3, figs. 18-20.

Ancyrodella curva ta, Over , p. 1 74, f ig . 1 1 -1 0- 1 1 .14.

Diagnosis: Ancyrodella curvata has a distinctive four lobed structure which makes it

easy to identify.

Material: 13 Pa elements.

Distribution: Sample 20 in the Long Rapids Formation type section.

Ancyrodella nodosa Ulrich and Bassler 1 926

Pl. 3, fig. 3

Ancyrodella nodosa Ulrich and Bassler, 1926, p. 48, pl. 1, figs. 10-1 3.

Ancyrodella nodosa, Klapper and Lane, 1985, p. 925, figs. 14.6, 14.7, 14.10, 14.1 1.

Ancyrodella nodosa, Norris etal., p. 72, 1992 pl. 16, figs. 1-6.

Ancyrodella nodosa, Morrow, 2000, p. 55, pl. 4, fig. 1.

Diagnosis: Ancyrodella nodosa is simi lar to Ancyrodella buckeyensis -but

distinguished by more pronounced surface nodes and a distinct constriction in the

posterior part of the platfom margin which gives the overall platfom shape two

different angles.

Remarks: The most plentiful of the ancyrodellids.

Material: 267 Pa elements

Distribution: Williams Island Formation type section, samples 1-6; Long Rapids

Formation type section, samples 7, 8, 1 0, 1 2-21 .

Genus Ancyrognathus Branson and Mehl, 1 934

Ancyrognathus asymmetricus Ulrich and Bassler, 1926

PI. 3, fig. 4

Ancyrognathus asymmetricus Ulrich and Bassler, 1926, p. 50, pl. 7, fig. 8.

Ancyroides asymmetrica, Müller and Müller, 1957, p. 1098, pl. 138, figs. 8,9.

Ancyrognathus asymmetrkus, Ziegler, 1973, p. 41, pl. 2, figs. 4,5.

Ancyrognathus asymmetricus, Klapper, 1989, p. 458, pl. 4, figs. 8, 12.

Diagnosis: Also a trilobate species, but outer and inner margins of the platfon are

straighter than Ancyrognathus calvini, and ends of the lobes are pointed. Lobes are

also distinctly asymmetrical.

Rernarks: This is the most plentiful of the Ancyrognathus species. They all die out at

the F/F boundary with the exception of Ancyrognathus ubiquitus which survives (but

not in the Long Rapids Fm.) briefly into the Famennian (Sandberg et al., 1988).

Material: 79 Pa elements.

Distribution: Samples 11, 14-21 of the Long Rapids Formation type section.

Ancyrognathus calvini Miller and Youngquist, 1947

PI. 3, fig. 5

Ancyroides calvini Miller and Youngquist, 1947, p. 504, pl. 75, fig. 4.

Ancyroides calvini, Müller and Müller, 1957, p. 1098. pl. 138, fig. 6

Ancyrognathus calvini, Ziegler, 1981, pl. 4, figs. 3-6.

Diagnosis: a subsymmetrical species with a rounded lobe, trilobate platform and a

short median blade.

Material: 4 Pa elernents.

Distribution: Samples 17. 19, 20 in the Long Rapids Formation type section.

Ancyrognathus triangularis Y ou ngq u ist , 1 945

PI. 3, fig. 6

Ancyrognathus triangularis Youngquist, 1945, p. 356. pl. 54, fig. 7.

Ancyrognathus triangularis, Ziegler, 1981, pl. 5, figs. 1-10.

Ancyrognathus tnangulans, Klapper, 1989, p. 458, pl. 4, figs. 6, 7.

Ancyrognathus tnangulans, Noms et al., 1992, p. 73, pl. 17, figs. 5, 6, 8, 9.

Ancyrognathus triangularis, Morrow, 2000, p. 53, pl. 3, fig. 8.

Diagnosis: A more or less triangular species with outer and inner rnargins relatively

straight and the angle between the main and secondary canna 90 degrees or more.

Remarks: This is the widest ranging of the ancyrognathids, found in the Williams

Island Formation type section up to the uppermost Frasnian (Kellwasser-like)

limestone bed (unit 22, or sample 18) in the Long Rapids Formation type section.

Material: 26 Pa elements.

Distribution: Williams Island Formation type section, samples 1-6; Long Rapids

Formation type section, samples 8, 9, 13, 17, 18.

Ancyrognathus ubiquitus Sandberg, Ziegler and Dreesen, 1 988

PI. 3, fig. 7

Ancyrognathus ubiquitus Sandberg , Ziegler and Dreesen, 1 988, pp. 297-298, pl. 1 ,

figs. 5, 6; pl 2, figs. 1-7.

Ancyrognathus ubiquitus, Schindler, 1 WOa, pl. 5, fig. 7.

95

Diagnosis: This species is recognized by its long, thin outer lobe (which is broken in

the single specimen recovered) and ovate inner platform. The free blade is also

absent in this specimen.

Remarks: All ancyrognathids died out at the boundary, except for

Ancyrognathus ubiquitus that suivived for a short time; however, at the Long Rapids,

only one (partially broken) specimen of ubiquitus was found.

Material: 1 Pa element.

Distribution: Sample 20, Long Rapids Formation type section.

Family Icriodontidae Müller and Müller, 1957

Genus lcriodus Branson and Mehl, 1938

lcriodus alternatus alternatus Branson and Mehl, 1934

PI. 3, fig. 8

lcriodus alternatus alternatus Branson and Mehl, 1934, pp. 225-6, pl. 13, figs. 4-6.

lcnodus alternatus alternatus, Wang and Geldsetzer, 1995, p. 1832, pl. 3, figs. 1 6-

19.

lcriodus altematus alternatus, Over, 1997, p. 168, fig. 10.14.

lcrbdus alternatus altematus, Morrow, 2000, p. 55. pl. 4, fig. 7.

Diagnosis: Central denticles altemate with side denticles in this common species.

Remarks: the icriodids survived the FIF extinction and are a shallow water species;

their significant increase in numbers around the boundary is interpreted to indicate a

marine regression (Sandberg et al., 1988).

Material: 160 Pa elements.

Distribution: Long Rapids Formation type section, samples 20-26.

lcriodus symmetricus Branson and Mehl. 1 934

Pl. 3, fig. 9

lcriodus symmetricus Branson and Mehl, 1934. p. 226. pl. 1 3, figs. 1-3.

Icriodus symmetricus, Ziegler. 1 973, pl. 3, figs. 7, 8.

lcriodus symmetricus, Norris et al., 1 992, p. 71, pl. 16. figs. 7-1 6.

lcriodus symmetricus, Morrow, 2000, p. 55, pl. 4. fig. 3.

Diagnosis: The three rows of denticles are more or less in line, distinguishing this

species frorn the previous one.

97

Remarks: lcriodus symmetricus is most prevalent in the Williams Island Formation

type section. whereas lcriodus altematus alternatus, which is also found in the

Williams Island Formation type section, doesn't proliferate until the highest Frasnian

and early Famennian.

Material: 99 Pa elements.

Distribution: Williams Island Formation type section, sarnples 1-6; Long Rapids

Formation type section, sampies 7, 10, 18, 20, 25.

Genus Polygnathus Hinde, 1 879

Polygnathus brevilaminus Branson and Mehl 1934

PI. 3, fig. 10

Polygnathus brevilamina Branson and Mehl, 1934. p. 246, pl. 21 , figs. 3-6.

Polygnathus brevilaminus, Orchard, 1988. p. 49, pl. 4, figs. 12, 18.

Polygnathus brevilaminus, Morrow, 2000, p. 57, pl. 5, fig. 11.

Diagnosis: A distinctive species where the platforni is only about one third the length

of the overall unit and the carina extends well below and above the platform.

Material: 12 Pa elements.

Distribution: Long Rapids Formation type section, samples 23, 25.

Polygnathus decorosus Stauffer, 1938

PI. 3, fig. 11

Polygnathus decorosus Stauffer, 1938, p. 438, pl. 53, figs. 5,6, 10, 15, 16.

Polygnathus decorosus, Klapper and Lane, 1985, p. 935, fig. 18.7.

Polygnathus decorosus, Norris et al., 1 992, p. 77, pl. 1 4, figs. 9- 1 7.

Polygnathus decorosus, Over, 1997, p. 174, fig. 10.1 1.

Diagnosis: A long, narrow species with a pointed posterior tip. free blade up to half

the unit length, and strong transverse ridges on the upper surface of the platform.

Remarks: The most long ranging of the polygnathid species in the Long Rapids

Formation type section.

Material: 4185 Pa elements

Distribution: Williams Island Formation type section, samples 1-6; Long Rapids

Formation type section, samples 7-20, 22, 24, 25.

Polygnathus elegantulus Klapper and Lane 1985

PI. 3, fig. 12

Polygnathus elegantulus Klapper and Lane, 1 985, p. 935, figs. 1 8.8-1 8.1 4, 2 1.8.

Diagnosis: A species of narrow to moderate width and symrnetrical overall shape

with the platforni and the free blade each about half the unit length.

Remarks: This species is present in the Palmatolepis linguiformis Zone and Early

Palmatolepis triangularis Zone.

Material: 5 18 Pa elernents.

Distribution: Long Rapids Formation type section. samples 20-25, 27.

Polygnathus evidens Klapper and Lane, 1985

PI. 3, fig. 13

Polygnathus evidens Klapper and Lane, 1985. p. 935, figs. 20.1 -20.8.

Polygnathus evidens, Norris et al., 1992, p. 78, pl. 14, figs. 18. 22-29.

Diagnosis: A very short free blade with large ascending denticles and a deep

adcarinal trough characterke this species.

1 0 0

Remarks: All specimens of Polygnathus evidens were found in the Williams Island

Formation type section.

Material: 12 Pa elements.

Distribution: Williams Island Formation type section, samples 2, 4-6.

Polygnathus webbi Stauffer, 1938

PI. 3, fig. 14

Polygnathus webbi Stauffer, 1938, p. 439, pl. 53. figs. 25, 26, 28, 29.

Polygnathus webbi, Klapper and Lane, 1985, p. 944, fig. 16.1 8.

Polygnathus webbi, Over, 1997, p. 174, fig. 10.13.

Diagnosis: A curved platform shape with subequal sides and a carina that continues

to the posterior tip characterize this species.

Remarks: although Polygnathus webbi was not supposed to have survived the F/F

extinction (Klapper et al., 1993) this is not the only section where this species ranges

into the Early Palmatolepis triangularis Zone (see Schindler et al., 1998, table 1 ).

Material: 17 Pa elements.

Distribution: Williams Island Formation type section, sample 4; Long Rapids

Formation type section, samples 9, 14. 15, 20, 22, 24.

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Plate 1 Al1 upper views except fig. 16 which is a lateral view. All Pa eiements except figs. 2, 9, 19 which are Pb elements

1.2. Palmatolepis delicatula delicatula, Long Rapids Formation type section, Sample 25, ROM #54107,54108, x100.

3. Palmatolepis ederi, Long Rapids Formation type section, Sample 20, ROM #54109, x70

4. Palmatolepis foliacea, Williams Island Formation type section, Sample 2, ROM #541 10, x6O

5. Palmatolepis foliacea, Williams Island Formation type section,Sample 1, ROM #54111, x80

6. Palmatolepis gigas gigas, Williams Island Formation type section, Sample 5, ROM #54112, x 70

7. Palmatolepis hassi, Long Rapids Formation type section, Sample 17, ROM #54113, x80

8. Palmatolepis hassi, Long Rapids Formation type section, Sample 20, ROM #54114, x60

9. Palmatolepis hassi, Long Rapids Formation type section, Sample 20, ROM #54115, x130

10. Palmatolepis jamieae, Long Rapids Formation type section, Sample 20, ROM #54116, x 80

1 1. Palmatolepis juntianensis, Long Rapids Formation type section, Sample 20, ROM #54 1 1 7, x120

12. Palmatolepis linguiformis, Long Rapids Formation type section, Sample 20, ROM #54118, x60

13. Palmatalepis minuta minuta, Long Rapids Formation type section, Sample 25, ROM #54119, x170

14. Palmatolepis plana, Williams Island Formation type section, Sample 1, ROM #5412O, x60

15, 1 6. Palmatolepis praetriangularis, Long Rapids Formation type section,Sample 20, ROM #54121, #15 x100; #16 x i 10.

17,18. Palrnatolepis praetriangularis, Long Rapids Formation type section, Sample 20, ROM #54122,54123, x100

19. Palmatolepis praetriangularis, Williams Island Formation type section, Sample 5, ROM #Wl24, x110

Plate 2 All upper views except fig. 4 which is a lower view and figs. 12, 14, 16 which are lateral views. All Pa elements except figs. 6, 10, 17 which are Pb elements.

1. Palmatolepis protohomboidea, Long Rapids Formation type section, Sample 25, ROM #54125, x170

2. Palmatolepis rhenana nasuta, Williams Island Formation type section, Sample 4 ROM #54126, x60

3. Palmatolepis rhenana rhenana, Williams Island Formation type section, Sample 4 ROM #54127, x80

4,s. Palrnatolepis rotunda, Long Rapids Formation type section, Sarnple 20 ROM #54128,54129, #4 x80; # 5 x100

6. Palmatolepis rotunda, Long Rapids Formation type section, Sample 20 ROM #Ml 30, x120

7. Palmatolepis cf. Pa. semichatovae, Long Rapids Formation type section, Sample 25, ROM #54131. x110

8, 9. Palmatolepis subrecta, Long Rapids Formation type section, Sarnple 20 ROM #Ml 32,54133, #8 x70, #9 x80

10. Palmatolepis subrecta, Long Rapids Formation type section, Sample 20 ROM #54134, x70.

1 1, 12. Palmatolepis triangularis, Long Rapids Formation type section, Sample 25, ROM #54135, #11 x100, #12 x100

13, 14. Palmatolepis triangularis, Long Rapids Formation type section, Sample 25, ROM #!XI 36, #13 x80, #14 x80

1 5, 16. Palrnatolepis triangularis, Long Rapids Formation type section, Sample 25, ROM #54137, #15 x60, #16 x60

17. Palmatolepis triangular~s, Long Rapids Formation type section, Sample 25, ROM #54138, x110

18. Palmatolepis ? Mutant element, Long Rapids Formation type section, Sample 20, ROM #54139, x120

Plate 3 All upper views except figs. 15-1 9 which have no standard orientation

1. Ancyrodella buckeyensis, Long Rapids Formation type section, Sample 20 ROM #54140, x8O

2. Ancyrodella curvata, Long Rapids Formation type section, Sample 20 ROM #54141, x100

3. Ancyrodella nodosa, Long Rapids Formation type section, Sample 20 ROM #54142, x100

4. Ancyrognathus asymmetricus, Long Rapids Formation type section, Sample 17 ROM #54143, x60.

5. Ancyrognathus calvini, Long Rapids Formation type section, Sample 20 ROM #54144, x80

6.Ancyrognathus triangularis, Long Rapids Formation type section, Sample 8 ROM #54145, x130.

7. Ancyrognathus ubiquitus, Long Rapids Formation type section, Sample 20 ROM #54146, x100

8. Icriodus alternatus alternatus, Long Rapids Formation type section, Sampling 20 ROM #54147, x100

9. lcriodus syrnmetricus, Williams Island Formation type section, Sample 3 ROM #54148, xl00.

10. Polygnathus brevalaminus, Long Rapids Formation type section, Sample 25 ROM #54149, x110

1 1. Polygnathus decorosus, Long Rapids Formation type section, Sample 20 ROM #54150, x70

12. Polygnathus elegantulus, Long Rapids Formation type section, Sample 22 ROM #54151, x110

13. Polygnathus evidens, Williams Island Formation type section, Sample 5 ROM #54152, x60

14. Polygnathus webbi, Long Rapids Formation type section, Sample 22 ROM #S4l53, x100

15, 16. Conodont pearls, Long Rapids Formation type section, Sample 20 ROM #54154,54155, #15 x300 #16 x220

17, 18, 19. Conodont pearls, Long Rapids Formation type section, Sample 20 ROM #54156, 541 57, #17 x220, #18 x200, #19 x500

Table 1 Selective Geochemical Sampling

of Long Rapids Formation type section

CaO Si02 Mgû , A1203 Fe203 Mn0 K20 Ti02 , Na20 P205 LOI TOTAL Ba , Sr Y Sc Zr Be V , , . . .

Sample 28

Sample 27

Sample 26

Sample 18

Sample 16

Sample 14

Sample 13

Sample 12

Sample 11 21.71, 16.98 14.29 4.53 3.82 0.18 1.14 0.24 0.1 0.07 33.82 96.86 113 43 34 5 58 -1 35 . . . , . .

Sample 10 22.41, 16.63 14.72, 4.66 3.63 0.19 1.21 0.24 0.09 0.06 34.67 98.51 118 45 35 6 54 -1 36 , , . , , ,

Sample 9 , 22.62, 16.93 14.84, 4.62 2.91 0.18 1.24 0.24 0.08 0.13, 34.98 98.77 120, 48 . 34 . 6 . 63 - 1 . 32

Sample 8 22.16, 18.03 14.48 4.49 3,05 0.17 1.32 0.26 0.08 0.14 34.37 98.56 124 .48 . , . 30 6 68 -1 30 . .

Sample 7 , 20.58, 21.72 13.42, 5.46 2.47 0.14. 1.56 0.3 0.08 0.04 32.76 98.53 147, 50 , 28 , 6 , 78 -1, 36

Sample 4 21.88 14.41 11.96 4.48 8.44 0.17 1.17 0.22 0.09 0.04 26.73 89.59 130 67 34 7 48 -1 33

Activation Laboratories minus sign (-) = less than (<)

-" t -" I - . L.. , - . -1

d -- . -Lir( . -.L.

air.-.. i i -ci.

I i -.-" ' 0 L I

. a , I -Li. 0 , u n 0 b W....

I I Li.,

. b - L m O , -.. i 1 r...,

I I -ci. I I - L W

., -6.. S I .-

., .CW

41 CC" I 1 -Li.

C D b 1 1 I i 1 r r 1 E I L o r ~ m r l r c i ~ L L I L C L U H ~ J 1 1 c 1 i m i O e r mc oc 1 cm 1 cm 1 o r 1 I O II I --- I I I 1 1 ~ l d l . , U ~

'III Il .- - -- I I I G nw1iu.w

el<, il I -- 1 I l II II

<I il II 1 I i # k l 1 # I L 1 # l - ,- a, **I,l,.,-~

l II C l --- ,- 1 " C I V i V I (, OI'1UI.W

'l'Il -- I I l I 1 1 I l I

- tiiuiurl: U I i O 1 1 1 " I I ; '7; 1 1 e s(<si- 011 <J I I I 1 1 1 8 cl V I I o r l a u i m ~ 1 <1 < l 1: 1; 2. -- ,-, I>L I~lllll'.Li

W I II 1; r. ' 3 / II I L 1 l O(LIIIIY~

- - -- l ' 1: 9 -T

l - - - . . . - - - - - - - . - . .

e i u l a u i ~ G

Il/ U 1 - 6 C l ~ l < l l I l W H

I O II 1 1 t I . L "I<1iiWti

r i 1: 1 , " 1 I i ( i IU i .~

UR2 - N 1

Table 4 Whole Rock Analysis of Boundary Strata

302 , A1203

?O, O10

Sampfe 25-3 52.23 13.01

Sarnple 25-2 52.19, 13.53

Sample 25-1 , 51.19 13.10

Sample 24 57.41. 14.79

Sample 23-6 52.20, 12.98

Sample 23-5 51.13, 13.43

Sample 23-4 51.68 13.39

Sample 23-3 53.02, 13.43

Sample 23-2 51 .91 13.16

Sample 23- 1 50.92. 12.74

Sample 22 38.67, 9.64

Sample 2 1-4 46.49, 11.87

Sample 21-3 44.75, 11.30

Sample 2 1 -2 45.82 10.82

Sample 21-1 44.66, 10.71

Sample 20-6 43.02, 10.52

Sample 20-5 , 44.19, 10.71

Sample 20-4 43.47, 10.74

Sample 20-3 43.44, 10.78

Sample 20-2 . 41.11, 10.47

Sample 20- t 37.69, 9.86

Sample 19 58.07, 14.27

Sample 18 29.42, 7.39

Sample 17 56.90, 13.69

Sample 16 30.68, 7.75

Sample 15 55.86 13.8;

N e g a l ~ e values indicaie los8 lhan the <leleclion Iimil LOI values lese than OOl?'. repiesenl a Gain on Igniiioii

P205, LOI,

O10 , % ,

0.08, 14.37 ,

0.10 17.21.

0.17, 16.91,

0.06, 10.86,

0.09, 17.00,

0.09, 17.89,

0.08 17.72,

0.09, 17.59,

0.09 17.51

0.09 17.89,

0.06, 22.35.

0.08, 20.44,

0.10. 22.47,

0.10. 20.94.

0.12, 21.33,

0.35, 22.70,

0.23, 22.18,

0.27, 21.90,

0.31, 21.81,

0.31, 22.83,

0.37, 22.48.

0.09, 11.12,

0.07, 27.58,

0.10, 12,lO.

0.08, 26.85,

TOTAL ,

?'O,

98.09,

98.68,

99.29,

100.24,

98.90.

98.67,

99.25,

100.85,

98.77,

100.1 1 ,

98.55,

99.74,

99.89,

99.58

98.77,

98.61 ,

98.83,

98.61,

98.92,

98.79.

98.7 1.

100.72,

98.92,

99.75,

98.87,

4.36 0.07 4.38 4.17 0.20 3.77 0.838 0.19 12.33 99.98 395 70 37 14 232 2 1141

C

Activalion Laboralories W b\

Table 5 Trace Element Analysis of

Boundary Strata

Snmple 25.3

Snmple 25.2

Ssmpls 25.1

hmpls 24

Srrnple 23.6

Sampla 234

Çample 23.4

Sarnpla 23 3

Sampls 23.2

Sainpla 23.1

Sampk 22

Ssmpls 21-4

Simple 21,3

Sampla 21.2

Sampls 21.1

Sampla 20.6

Simple 20 5

Sampls 20,4

S~mpla 10.3

Sirnpla 20.2

Simple 20.1

Sarnpk 19

s m p b re

Samplr 17

Sunple 16

S m d e 15

3

NI, AO. AS, R1i, B R , CA CO, C11, CS, FE , IIF 110, 111, MO, NA, NI, AB, SB, SC S E , SN, Sn, H, ni, U , W , ZN, L A , CE, NO, SM, EU, 10, YB, LU,Msu

PPO, PPM, PPM, PI%, PPM, .. , PI'M PPM, PPM, a. t'PM l'PM, PPO, P m , h , PFM, PFM, t'PM, PPM PPM, .. *. , PPM f3PM, PPM, PPM, PIW, PPM, ['PM. Pm, PPM, PPM. PPM, PPM PI'M, 9

16. 12, 145.

15, 123. 161,

22, 133, 164,

.05, 1 1 1 , 106,

05, 118, 14,

0 5 , 123 138

11, 122, 127,

13, 1 1 1 , 1 1 8.

-05, 112 132

OS, 1 1 1, 129,

05, 98, 8,

10 107, 1 1 1 ,

05. U2. 89.

15, 9 2 , 88.

15, 8 8 R B ,

13 , 00, 8 7 ,

.O!+, 10 1 , 86,

05, 04, 7 1

05. 97, 91,

0 6 . 104. 85,

05. 10 12,

-05, 1 1 3, 08,

0 5 , 81, 43,

17, 1 1 4, 5 2 ,

05, 6 5 . 3,

8, 18, 30, 05, 8646

4, 1 , 35, 046, 9

2, 12, 38, 048, 9262

3, OB, 38, 045, 8757

5 1 , 3, 0 % . 8778

Activation Laboratories minus (-) = less han (<)

Table 7 Iridium Content

Sample 25-3

Sample 25-2

Sample 25-1

Sample 24

3ample 23-6

;ample 23-5

:ample 23-4

:ample 23-3

:ample 23-2

$ample 23-1

$ample 22

;ample 21-4

;ample 21-3

;ample 21-2

iample 21-1

;ample 20-6

;ample 20-5

;ample 20-4

;ample 20-3

;ample 20-2

;ample 20-1

;ample 19

;ample 18

;ample 17

,ample 16

IR

PPB

0.9

O .2

0.2

0.1

0.2

0.3

1.3

1.1

0.2

0.2

0.2

0.3

0.2

0.2

0.2

0.3

0.3

0.3

0.3

0.3

0.3

0.2

0.4

0.7

0.6

4

Activation Laboratories