Eocene and Oligocene radiolarian biostratigraphy from the Southern Ocean: correlation of ODP Legs 114 (Atlantic Ocean) and 120 (Indian Ocean)

ELSEVIER Marine Micropaleontology 30 (1997) 97-116

Eocene and Oligocene radiolarian biostratigraphy from the Southern Ocean: correlation of ODP Legs 114 (Atlantic Ocean)

and 120 (Indian Ocean)

Atsushi Takemura a,*, Hsin Yi Ling b

“ Geoscience Institute. Hyogo University of Teacher Education, Yashim-cho, Kato-gun, Hyogo 673-14, Japan b Department of Geology, Northern Illinois University, DeKalb, IL 60115, USA

Accepted 15 April 1996

Abstract

Eocene-Oligocene radiolarians from Ocean Drilling Program Sites 699, 702, and 703, Leg 114 of the Subantarctic Atlantic were examined in order to extend the tripartite zonation for the recovered cores based on results of similar analysis of Leg 120 submarine sediments from the Indian Ocean. Correlation of the two oceans is made by examining 23 biohorizons and the three zones, Eucyrtidium spinosum, Axoprunum irregularis, and Lychnocanoma conica, in ascending stratigraphic order. One new species, Eucyrtidium nishimurae, is described.

Keywords: biostratigraphy; radiolaria; Eocene; Oligocene; ODP; Antarctic Ocean

1. Introduction

Like other microfossils, our knowledge of radiolarians in the Antarctic Ocean has improved re- markably during the last two decades. The results of Deep Sea Drilling Project (DSDP) Legs 28, 29, 35 and 36 clearly established a Neogene biostratigraphy, but Paleogene sections remained nearly untouched. It was after the cruises of Ocean Drilling Program (ODP) Legs 113 and 114 in the South Atlantic Ocean, and Legs 119 and 120 in the Southern Indian Ocean that the Paleogene and Neogene biostratigraphic framework was added to nearly complete the entire Cenozoic (Abelmann, 1990, 1992; Lazarus, 1990, 1992; Caulet, 1991; Takemura, 1992).

Most studies on Antarctic radiolarians, however,

* Corresponding author.

have focused on the Neogene, and few researchers reported on Paleogene radiolarians. Petrushevskaya (1975) and Chen (1975) reported some Eocene and Oligocene radiolarians from DSDP Legs 29 and 28, respectively. Weaver (1983) also reported Eocene and Oligocene radiolarians from DSDP Leg 71, but the occurrence of radiolarians in these DSDP Leg studies are quite sporadic.

Abelmann (1990) proposed a Late Oligocene to Middle Miocene biostratigraphy in the Antarctic sec- tor of the Atlantic Ocean, Sites 689 and 690 of ODP Leg 113. She made the first radiolarian zonation for the Antarctic Paleogene, although her samples were restricted to the Upper Oligocene. Caulet (1991) reported well-preserved Paleogene radiolarians ranging from the Middle Eocene to Oligocene at Sites 738 and 744 of ODP Leg 119 on the Kerguelen Plateau, southern Indian Ocean.

0377-8398/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SO377-8398(96)00017-5

98 A. Takemura, H. K Ling/Marine Micropaleontology 30 (1997) 97-116

Takemura (1992) studied well-preserved radiolarians from the Middle Eocene through Oligocene at Sites 748 and 749 of ODP Leg 120, on the Ker- guelen Plateau, and proposed a radiolarian zonation for this interval. Site 748, located on the south- em Kerguelen Plateau, yields a mostly continuous section containing well-preserved Paleogene radiolarians. He proposed three new zones for the Late Eocene through Oligocene.

was excluded from the present investigation because the submarine section from the site is limited to the Upper Oligocene only (Ciesielski and Kristoffersen et al., 1988).

The radiolarian occurrences at these Atlantic sites were compared with the results of Leg 120 from the Indian Ocean in order to establish a workable Late Paleogene zonation in the Antarctic Ocean.

All the studies in the Antarctic Ocean mentioned above show that the Paleogene radiolarian fauna is different from the low latitudes, and that a separate high-latitude zonation is needed. Sanfilippo et al. (1985) have established the Cenozoic radiolarian zonation in low latitudes, but most species used in low-latitude zonation do not occur in the Antarctic Paleogene.

2. Samples and methods of study

Seeking insight in these problems, Leg 114 of the Ocean Drilling Program (ODP) in 1988 sailed to the subantarctic Atlantic as the second of two cruises in the high-latitude South Atlantic Ocean. Among seven sites (698-704) drilled during the cruise, well- preserved Eocene to Oligocene radiolarians were recovered from Sites 699,701,702 and 703. Site 701

In the present study, we discuss Eocene-Oligo- cene radiolarians recovered from Sites 699, 702 and 703 (Fig. 1). The biostratigraphy of co-occuring microfossils was reported by Nocchi et al. (1991) for foraminifers, Crux (1991) and Madile and Monechi (1991) for calcareous nannofossils, and Ciesielski (1991) for silicoflagellates. Magnetostratigraphy for the sites was documented by Hailwood and Clement (1991a,b) and Clement and Hailwood (1991). The following is a brief summary of lithology and geologic ages for the Eocene-Oligocene sites under consideration (Ciesielski and Kristoffersen et al., 1988).

3O”W 0” 30”E

60°E

6O”W

9O”W 90’E

1 20°w 120”E

15O”W 180” 150”E

Fig. 1. Index map showing the locality of ODP sites examined in this study.

A, Takemura, H.1 Ling/Marine Micropaleontology 30 (1997) 97-116 99

2.1. Hole 699A

Site 699 is located on the northeastern slope of the Northeast Georgia Rise in the western South Atlantic Ocean (51”32.537’& 30“40.619’W) at a water depth of 3705 m. The Eocene to Oligocene sequence at this site is from samples lOH-1, 110 cm to 53X, CC (85.7-487.9 mbsf). This part of the section is composed in ascending order of nannofossil chalk, siliceous nannofossil ooze, nannofossil siliceous ooze, and nannofossil diatom ooze and diatom mud. A thin gravel layer is intercalated at about 235 mbsf (Core 26X).

The Oligocene/Miocene boundary was identified within the lower part of Core 1OH (approx. 91-94 mbsf) by Ciesielski and Kristoffersen et al. (1988) and by Hailwood and Clement (1991a), while Crux (1991) using nannofossils placed the boundary between Samples 1 lH-5,8-9 cm and 1 lH, CC (approx. 101-102 mbsf). The Early/Late Oligocene boundary was placed within Section 699A-21H-1 (approx. 189-191 mbsf) by Ciesielski and Kristoffersen et al. (1988).

The Eocene/Oligocene boundary also slightly dif- fers among the microfossil groups. Using nannofossils, Ciesielski and Kristoffersen et al. (1988) placed this boundary between Samples 32X, CC and 34X, CC (approx. 297-316 mbsf), whereas Crux (1991) used nannofossils to define it between Samples 32X-1, 83-84 cm and 33X-5,60-61 cm (288.43-303.71 mbsf). Data from foraminifers and paleomagnetism are too incomplete to delin- eate this boundary. The underlying sediments examined during the present study, Cores 35X to 37X (316.1-344.6 mbsf), are probably Late Eocene.

2.2. Holes 702A and 702B

Site 702 is located on the central part of the Islas Orcadas Rise in the western South Atlantic Ocean (50”56.786’S, 26”22.117’W) at a water depth of 3083 m. Lying directly below Middle Miocene sediments, Eocene nannofossil chalk and ooze were recovered from Hole 702, Core 4H and Hole 702B, Cores 4X through 26X (25.3-243.8 mbsf), but radiolarians below Core 14X (129.8 mbsf) are mostly poorly preserved and their occurrence is low.

Ciesielski and Kristoffersen et al. (1988) (nanno-

fossils and foraminifers) and Crux (1991) (nannofossils) placed the Middle/Late Eocene boundary between Samples 702B-5X, CC and 702B-6X-2,69-70 cm (44.3-46.5 mbsf). Nocchi et al. (1991), however, used foraminifers to identify this boundary between Samples 702B-6X-2, 25-27 cm to 702B-6X, CC (46.05-53.8 mbsf).

2.3. Hole 703A

Site 703 is located on the Meteor Rise in the Indo- Atlantic Basin (47”03.042’& 07”53.679’E) at a water depth of 1796 m. Although the subsurface section is composed of calcareous ooze and chalk of Quater- nary through Middle Eocene age throughout the Hole before porphyritic basalt or basaltic andesite was penetrated at the bottom (40X and 41X, 361.9-377.4 mbsf), Paleogene radiolarians were recovered only from the Upper Eocene to Upper Oligocene interval (Cores 5H to 18X, 33.4-162.4 mbsf).

The Miocene/Oligocene boundary was placed between Samples 703A-4H, CC and 703A-5H, CC (33.4-42.9 mbsf) by Ciesielski and Kristoffersen et al. (1988) (nannofossils), and between Samples 703A-5H-2,20-21 cm and 703A-5H, CC (35.1-42.9 mbsf) by Crux (1991) using nannofossils. While the Early/Late Oligocene boundary was drawn at between 703A-7H-3, 120 cm and 703A-7H-4, 130 cm (55.6-57.2 mbsf) by Ciesielski and Kristoffersen et al. (1988), Nocchi et al. (1991) using foraminifers placed the boundary around Sample 703A-7H-3, 124-126 cm (around 55.65 mbsf).

The Eocene/Oligocene boundary was placed between Samples 703A-12H, CC and 703A-13H, CC (109.4-l 18.9 mbsf) by Ciesielski and Kristoffersen et al. (1988). However, Nocchi et al. (1991), by recognizing the last continuous occurrence of Glo- bigerinatheka index from Sample 703A-14H, CC, placed the boundary between Samples 703A-13H, CC and 703A-14H, CC (118.9-128.4 mbsf), and this was supported by the calcareous nannofossil data of Madile and Monechi (1991).

The Middle/Late Eocene boundary lies within the interval between Samples 703A-18H, CC and 703A-19H, CC (162.4-171.9 mbsf; Ciesielski and Kristoffersen et al., 1988).

100 A. Takemura, H.E Ling/Marine Micropaleontology 30 (1997) 97-116

2.4. Methods of preparation

The methods for treatment of the samples for extracting radiolarians have already been described (Takemura, 1992). Briefly, the samples were pro- cessed with HCl (about 3%), followed by Hz02 and sodium pyrophosphate (or Calgon). Residues were sieved through 250-mesh (63 pm) sieves, dried and kept in vials. Both slides for transmitted light microscope and specimens for SEM (scanning electron microscope) were prepared from these residues.

The methods for preparing microslides were the same as those described previously by Sakai (1980) and Takemura (1992). Dried residues were scattered on slides which were coated with thin gum tra- gacanth. Radiolarians which did not adhere to the slides were allowed to fall off and removed with a brush. Canada balsam was used as a mounting medium.

In the present study, we identified and counted about 500 radiolarians in each sample, at a sample spacing of approximate one sample per core (Tables l-3). The remaining portion of the slide was also examined to ascertain the occurrence of key taxa.

3. Radiolarian occurrences from the Southern Atlantic

The radiolarian fauna of the Middle Eocene through Oligocene from the Southern Atlantic contains numerous species of nassellarians and spumellarians (Tables l-3). Because we cannot describe all the species in this paper, the following descriptions of radiolarian fauna from each site are based mostly on biostratigraphically useful taxa.

Among the unreported taxa there are numerous nassellarian forms, mostly of Theoperids and Plag- oniids, which have not been described yet. The occurrences of these forms, however, are usually rare or few and sporadic. Moreover, the classification of many forms, e.g. Acanthodesmiids, Plagoniids and most spumellarian groups, is difficult at present.

3.1. Hole 699A (Table 1)

Oligocene and Eocene radiolarians from 699A- lOH-2, 50-52 cm through 699A-37X-2, 4143 cm (86.60-337.01 mbsf) were examined in this study.

We counted radiolarian shells in one sample per core (9.5 m long), but sometimes this sample interval was interrupted because of poor recovery.

Samples from 699A-lOH-2, 50-52 cm to 699A- 18H-2,50-52 cm (86.60-162.60 mbsf; Upper Oligo- cene) contains abundant Lychnocanoma conica and Cyrtocapsella robusta, and common Calocyclas sp. A and Cycladophora conica. Vellicucullus alms is rare in the upper part of this horizon. Eucyrtid- ium antiquum sporadically occurs within this interval. As to spumellarians, Stylosphaera spp. occurs abundantly in Samples 699A-16H-2, 24-26 cm and 699A-17H-2,50-52 cm (143.34-153.10 mbsf).

Radiolarian faunas from Samples 699A- 19H-2, 50-52 cm through 699A-24X-3, 49-51 cm (172.10-218.09 mbsf), which is upper Lower Oligo- cene, usually include Lychnocanoma conica and Ax- opt-unum irregularis. Cyrtocapsella robusta rarely occurs and few Eucyrtidium antiquum occur at the lower part ofthis horizon. Calocyclas cf. semipolita has not been observed within this interval.

Calocyclas cf. semipolita (including its large forms) occurs abundantly in Samples 699A-27X-4, 133-135 cm through 699A-33X-3, 50-52 cm (248.93-300.60 mbsf; lower Lower Oligocene). Eucyrtidium antiquum, Lithomelissa sphaerocephalis and Lophocyrtis spp. (including L.(?) longiventer) occur commonly, while few Axoprunum irregularis and Eucyrtidium spinosum were identified in this interval. Periphaena spp., which includes both r( decora and p heliasteriscus, is contained in all samples from this interval.

Samples from 699A-35X-4, 50-52 cm to 699A- 37X-2, 4143 cm (321.10-337.01 mbsf; Upper Eocene) contain common Lophocyrtis spp., Calocy- clas cf. semipolita, Axoprunum pierinae and Eucyr- tidium spinosum. Oligocene species such as E. antiquum (s.s.) or A. irregularis have not been observed.

3.2. Site 702 (Table 2)

Radiolarians from Holes 702A and 702B (Sam- ples 702A-4H-2, 50-52 cm to 702B-14X-2, 5&52 cm; 25.60-122.30 mbsf) were examined from this site. One sample was observed and counted from each core.

Eucyrtidium spinosum has been observed in Sam-

A. Takemura, H. I: Ling /Marine Micropaleontology 30 (1997) 97-l 16 101

ples 702A-4H-2, 50-52 cm and 702B-5X-2, 50-52 cm (25.60-36.80 mbsf). Culocyclus cf. semipolita and Lophocyrtis spp. are abundant, and Calocyclas sp. B, Eucyrtidium nishimurae n. sp., Axoprunum pierinae and Periphaena spp. are common within this interval.

Within the interval between Samples 702B- 6X-2, 48-50 cm and 702B-14X-2, 50-52 cm (46.28-122.30 mbsf), species vary in abundance through the column. Lychnocanoma amphitrite, Lophocyrtis biaurita and Lophoconus titanoth- ericeraos are sometimes abundant. Lophocyrtis spp. (including L. dumitricai and L.(?) longiventer; San- filippo, 1990) are few to abundant. Lophocyrtis dumitricai consistently occurs within this interval, while this species has not been observed in the upper sequences. Calocyclas sp. C occurs only in two samples in the upper part of this interval.

3.3. Hole 703A (Table 3)

Samples 703A-5H-6, 55-57 cm through 703A- 18X-3, 50-52 cm (41.45-156.40 mbsf) were observed and counted. The age of this interval ranges from Late Eocene to earliest Miocene.

Samples 703A-5H-6, 55-57 cm through 703A- 7H-1, 50-52 cm (41.45-52.90 mbsf) contain common Lychnocanoma conica, and sporadically Calo- cyclas sp. A, Cyrtocapsella robusta and Cyclado- phora conica. Axoprunum irregularis has not been observed in this interval. The occurrence of Cyrto- capsella tetrapera in Sample 703A-5H-6, 55-57 cm (41.45 mbsf) shows that this horizon should fall in the Lower Miocene.

Radiolarians from Samples 703A-8H-2, 70-72 cm to 703A-llH-4, 40+2 cm (64.10-95.30 mbsf) commonly include Axoprunum irregularis and Gory- thospyris aff. jubutu. The lowest occurrence of Ly- chnocunoma conica (s.s.) is at Sample 703A-9H-2, 36-38 cm (73.26 mbsf). Calocyclas cf. semipolita rarely occurs in this interval. Eucyrtidium antiquum was observed consistently from Samples 703A-9H-2, 36-38 cm to 703A-13H-3, 60-62 cm (73.26-l 13.00 mbsf).

Samples 703A-12H-2, 60-62 cm and 703A- 13H-3,60-62 cm (102.00 and 113.00 mbsf) contain abundant Calocyclas cf. semipolita. Lophocyrtis spp. is also common to abundant. The first occurrence

of Axoprunum irregularis (s.s.) is at 703A-12H-2, 60-62 cm (102.00 mbsf).

Lophocyrtis spp., Calocyclas cf. semipolita and Axoprunum pierinae are common to abundant in the interval between Samples 703A-15H-2, 55-57 cm and 703A-18X-3, 50-52 cm (130.45-156.40 mbsf). Eucyrtidium spinosum consistently occurs within this interval. The last occurrence of Calocyclas sp. B (s.s.) is in Sample 703A-16X-1, 50-52 cm (138.40 mbsf).

Theocyrtis tuberosa occurs only in Sample 703A- 17X-1, 40-42 cm (143.80 mbsf). The adjacent two samples, 703A-16X-1, 50-52 cm (138.40 mbsf) and 703A-17X-3, 4a2 cm (146.80 mbsf) do not contain this species. This occurrence is the same as in Hole 748B of ODP Leg 120, in the Southern Indian Ocean, where the occurrence of T tuberosu is also restricted to only one sample, 748B-16H-2, 45-47 cm.

4. Eocene-Oligocene radiolarian biostratigraphy

4.1. Review

Petrushevskaya (1975) and Chen (1975) were the first to report the occurrence of Eocene and Oligocene radiolarians from DSDP Legs 29 and 28, respectively. Later, Weaver (1983) also reported Eocene and Oligocene radiolarians from DSDP Leg 7 1, but only the occurrences of radiolarians are mentioned and neither taxonomy nor a zonation were presented.

During the ODP Leg 113 cruise in the Weddell Sea, Sites 689 and 690 penetrated into Upper Oligo- cene sediments, and Abelmann (1990) proposed the Cyrtocapsella robusta Zone in the Upper Oligo- cene and Stylosphaera radiosa Zone for the Upper Oligocene to Lower Miocene. Ling (in Ciesielski and Kristoffersen et al., 1988) briefly mentioned the occurrence of Eocene and Oligocene radiolarians from all seven sites drilled during Leg 114 from the subantarctic Atlantic. From the submarine section of Sites 738 and 744 of Leg 119 at the Kerguelen Plateau (Southern Indian Ocean) Caulet (1991) reported well-preserved radiolarians and recognized radiolarian events, but did not propose any zonation. Based on samples Sites 748 and 749 of ODP Leg 120 from the southern Kerguelen Plateau,

102

Table 1

A. Takemura, H. K Ling / Marine Micropaleontology 30 ( 1997) 97-l 16

Eocene to Oligocene radiolarian occurrences in Hole 699A

Takemura (1992) proposed the Eucyrtidium spinosum, Axoprunum(?) irregularis, and Lychnocanoma conica zones (in ascending order) for the interval.

All the above analyses from the Antarctic Ocean reveal that the Paleogene radiolarian faunas are different from those of the low latitudes (e.g. Sanfilippo et al., 1985). Consequently a separate zonal scheme is needed for the area.

4.2. Zonation in the Atlantic and Indian Ocean

One of the main objectives of our present paper is to establish a workable biostratigraphic framework for the entire high-latitude southern oceans, south of the Subantarctic Convergence. We applied a zonal scheme proposed by Takemura (1992) from Leg 120 of the Indian Ocean as a basis for comparing the radiolarian occurrences within the submarine sections

from three sites of Leg 114 from the Atlantic: 699, 702 and 703. It soon became evident during our study that some emendations to the zonation were neces- sary, and they are discussed in ascending order below. Biohorizons recognized and used for the correlation between the two oceans are listed in Table 4, showing paleomagnetic calibration of each horizon. Table 5 shows estimated ages of biohorizons using these paleomagnetic results. The correlation between the Southern Indian Ocean and the South Atlantic via these biohorizons is illustrated in Fig. 2, and the ranges of some selected species are also shown in Fig. 3.

In the zonation which follows, we begin with Late Eocene. Middle Eocene radiolarians have been observed in Sites 748 and 702. Takemura (1992) reported some probably useful biohorizons within the Middle Eocene of Site 748. At Site 702, the usefulness

A. Takemura, H.Y. Ling/Marine Micropaleontology 30 (1997) 97-116 103

Table 1 (continued)

1 E p + i-_.; b.y r___.j i__ _i 1 .-.j

I.- ..t

;.._.._~

i _-_..j

-+ L.. _.._ /__ _..j

.----T

L.._._;

___..+

.-..A

._?..j 1 i

‘- ‘-7 -...... 1 , /

. . . ..-i Oi _ _..+ 0’

__....+

i

-..._.+

.-..$

i

Occurrence number 0 shows that some specimens had been observed but only scanning the remainder at the slide after counting. ‘?’ means a questionable identification of the species. Abundance: A, abundant; C, common; F, few. Preservation: G, good M, medium; P, poor. Radiolarian taxa are listed by families of Riedel (1967) as Nassellaria, which are bounded by longitudinal solid black lines. Horizontal solid lines show the boundary of radiolarian biozones

of these biohorizons for correlation, however, could not be examined sufficiently because of the scarcity of samples in this study. The first appearance of &lo- cycZus sp. B, and the last appearances of Sethocyrtis sp. and Culocyclas sp. C are observed in the interval between Samples 702B-6X-2, 48-50 cm and 8X-2, 20-22 cm (462865.00 mbsf), where the core recovery was low because of drilling disturbance.

These three bioevents are within the upper part of Middle Eocene section at both sites, 748 and 702. In Hole 748B, the LAD of Sethocyrtis sp. is situated between two planktic foraminifer datums, the LAD of Subbotina Einaptera S.S. and the LAD of Acarin- ina primitiva and within calcareous nannoplankton Zones NP15 to 17 (Berggren, 1992; Aubry, 1992).

The FAD of CuZocyclas sp. B nearly coincides with the LAD of A. primitiva and the LAD of CuZocyclas sp. C is below this foraminifer bioevent, while both datums are included within nannoplankton Zones NP15 or 16.

At Site 702, these three radiolarian datums are situated near or below LAD of Acurinina primitiva (between Samples 702B-6X-2,25-27 cm and 702B-6X, CC, 46.05-47.3 mbsf; Nocchi et al., 1991). They also lie within calcareous nannoplankton Zones NP16 or 17 (Crux, 1991).

Eucyrtidium spinosum Zone (Takemura, 1992) Top: first appearance of Eucyrtidium antiquum. Bottom: first appearance of Eucyrtidium spinosum.

104 A. Takemura, H. K Ling /Marine Micropaleontology 30 (1997) 97-116

Table 2 Middle to late Eocene radiolarian occurrences in Holes 702A and 702B (abbreviations as in Table I)

! / igl ; jo1 ; 10; ; j i ._.,,,,.. .,_..._; _ ,,.. _.f..__...)_ .,... _~-.__.+._..._+ .._,., _t___i_____i__,..t.......-’ .,., _+......

i :13i i ;I; : i j i i ,........ j._.._.+ ..,,,.,.. I_ i”““““‘._ ++..._~__.._~_.._ 18 .._... ; ; j , /

_ .,.. .-T”“_‘.‘~_ 1 ;

: / i i / j 1 : : : 139

.._ T*! _..._ _+.m.,,~__.t___i ._.“. _‘p‘_._.._ *_._.~ ___._ +.._. i : 14; ; ; 12: ;3!12!57

_._.._. _...... _f....._...~_..~...~” . . . . . _ ._.. _~_._l..___i.._._...~.._._i__.._f-___~.”_.._. i , ; ‘01 ; $ i ; i391 1 ..., _ ,.., ._ 4 ,.,_.. _.,; py...._...~~_ +.._‘_‘r”_.._l’_ ,.,.,. .p__.__f...__,.i_.._ p_.._.

,._.,..._ _ ,.,. . ..!. ,,,.,.. i ,,.. ; i _ .,,, I..p...i ,,,..,, .i. ..,. ..i _LL.....i.. .,,, _1....._1.521..._.... / : ;jI i’ 1 ; ; i i ilf5 / I x

. 1X-2.50-52 1 122.30[1 j i 156i , jl!Oi j i i j 1 i ; 3 j 95 i ; 39 ,,

Reference section. Site 748: 748B-17H-1, 45-47 cm to 17H-2, 45-47 cm (143.05-144.55 mbsf). Site 702: 702B-5X-2, 50-52 cm to 6X-2, 48-50 cm (36.80-46.28 mbsf).

Correlation: The base of the zone nearly coincides with the LAD of Subbotina linaperta S.S. (foraminifer), which is used to determine the Mid-

die/Late Eocene boundary at Site 748 (17H- 1,80-84 cm to 17H-2, 80-84 cm, 143.40-144.90 mbsf; Berggren, 1992). The probable normal polarity of paleomagnetism around this horizon is correlated to Subchron C17N. It is also situated just above the bottom of the calcareous nannoplankton NP18 Zone (17H-3, 70 cm to 17H-4, 70 cm, 146.30-147.80 mbsf; Aubry, 1992).

A. Takemura, H.E Ling/Marine Micropaleontology 30 (1997) 97-116 105

Table 3 Eocene to Oligocene radiolarian occurrences in Hole 703A (abbreviations as in Table 1)

(cm)

At Site 702, the base of this zone nearly coin- tides with Middle/Late Eocene boundary (between Samples 702B-5X, CC and 702B-6X-2, 69-70 cm; 44.3-46.5 mbsf) of Ciesielski and Kristoffersen et al. (1988) and Crux (1991), but it is probably above the Middle/Late Eocene boundary as defined by the last occurrence of a foraminifer species, Acarinina

primitiva (6X-2, 25-27 cm to 6X, CC, 46.05-53.8 mbsf; Nocchi et al., 199 1). However, Berggren (1992) placed the LAD of A. primitiva in the interval from 748B- 18H- 1,40-44 cm to 18H-2, 80-84 cm (152.50-154.40 mbsf), which is below the bottom of this zone and is within the Middle Eocene. The base of this zone is also correlated to calcareous

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A. Takemura, H.Z Ling/Marine Micropaleontology 30 (1997) 97-116

699 Radiolarian Zones

INDIAN OCEAN

SOUTH ATLANTIC

Fig. 2. Correlation of ODP Paleogene sequences in the South Atlantic and Southern Indian Ocean by radiolarian b&vents. below each ODP site show core numbers. Numbers of each correlation line are bioevents shown in Table 4.

nannofossil zones NP18 or 17 at Site 702 (Ciesielski and Kristoffersen et al., 1988; Crux, 1991).

Other biohorizons: The FAD of Theocyrtis diabloensis is found just below (Hole 748B) or at the same horizon (Hole 699A) as the top of this zone. This species, however, rarely occurs in Hole 703A.

The LAD of Zygocircus biitschlii is also observed just below the top of this zone in Holes 748B and 699A, but in Hole 703A, the datum occurs within the overlying A. irregular-is Zone.

The correlation of the LAD of Calocyclas sp. B and the occurrence of Theocyrtis tuberosa with magnetostratigraphy is somewhat difficult because of the scarcity of the latter data. In Hole 748B, the LAD of CalocycEas sp. B could be within Subchron C16N, but the magnetostratigraphic horizon of the occurrence of T. tuberosa is unknown. No magnetozone interpretation is available for the equivalent depth intervals in Holes 699A and 703A.

The LAD of Calocyclas sp. B is included within

Numbers

Fig. 3. Ranges of selected Paleogene radiolarians used for correlation in this study.

calcareous nannofossil Zone NP18 in Holes 748B and 703A, and NP19/20 or NP18 in Hole 699A (Aubry, 1992; Crux, 1991; Madile and Monechi, 1991).

108 A. Taknura, H.k: Ling/Marine Micropaleontology 30 (1997) 97-116

Theocyrtis tuberosa occurred only within this Zone, in Samples 748B-16H-2, 45-47 cm (134.85 mbsf) and 703A-17X-1 (143.80 mbsf), 40-42 cm, both were placed within nannofossil Zone NP18. The morphology of this species in the southern high latitudes resembles that of the earlier forms of 7: tuberosa in the low latitudes, which has indistinct longitudinal ribs (Sanfilippo et al., 1985).

Axoprunum irregularis Zone (Takemura, 1992) Top: the last appearance of Axoprunum irregu-

laris. Bottom: the first appearance of Eucyrtidium an-

tiquum. Reference section. Site 748: 748B-14H-2, 4547

cm to 14H-3, 45-47 cm (116.05-l 17.55 mbsf). Site 699: 699A-33X-3, 50-52 cm to 35X-4, 50-52 cm (300.60-321.10 mbsf). Site 703: 703A-13H-3, 60- 62 cm to 15H-2,55-57 cm (113.00-130.45 mbsf).

CorreZation: Although the bottom of this zone is observed in Holes 748B, 699A and 703A, magnetostratigraphic interpretations and/or sample intervals treated in this study are not sufficient to determine the horizon in all these sites. At Hole 748B, Wei et al. (1992) proposed the reinterpretation of magnetostratigraphy above the Eocene/Oligocene boundary. According to his study, the base of this zone may be placed within Subchron C 13R, in which the Eocene/Oligocene boundary is also included. Following the magnetostratigraphy by Hailwood and Clement (1991b) at Site 703, the base of this zone is correlated with the interval from Sub&on C12R to C13R.

The base of this zone is situated slightly above or is nearly same as the horizon of the last appearance of the foraminifer Globigerinatheka index. In Hole 748B, where a continuous sequence was recovered, the base of this zone is placed about 3 to 6 m above the latter horizon (Berggren, 1992). It also lies within the range of calcareous nannofossil species Reticulofenestra oamaruensis (Crux, 1991; Madile and Monechi, 1991; Wei et al., 1992). According to Wei et al. (1992), an abrupt increase of cool-water calcareous nannofossil taxa, a large positive shift of al80 values of planktic foraminifers and occurrences of ice-rafted debris are reported just above the base of this A. irregularis Zone at Site 748.

Remarks: In the lower part of this zone, various forms of Calocyclas cf. semipolita occur abundantly. Although Takemura (1992) has not mentioned this biostratigraphic event, the last abundant occurrence of this species can be easily placed at Sample 748B- 13H-1,45-47 cm (105.05 mbsf).

Other biohorizons: The FAD of Calocyclas sp. A seems to slightly vary in age among four sites (748, 749, 699 and 703; Tables 4 and 5). At Indian Ocean Sites 748 and 749, it is included in the Early Oligo- cene, but in the Atlantic Ocean, this datum is close to the Early/Late Oligocene boundary. This species occurs less frequently in the Southern Atlantic than in the Southern Indian Ocean.

The FAD of Lychnocanoma conica falls within Subchron CllN or CllR in Hole 748B, Subchrons ClOR to CllR in Hole 699A, and ClOR or CllN in Hole 703A. This datum is thus approximately equivalent to Subchron Cl 1N.

The last abundant occurrence of Calocyclas cf. semipolita is within Subchron C12N or C12R in Hole 748B, CllR to C13N in Hole 699A, and C12N or C12R in Hole 703A. Both the paleontological and paleomagnetic data are rather poor at this horizon in Hole 699A, because a gravel layer is intercalated. This datum is approximately equivalent to C12N or C12R.

The identifications of magnetozones at lower hori- zons in the Lower Oligocene are not sufficiently clear in these holes to precisely correlate with the radiolarian biohorizons. The LAD of Eucyrtidium spinosum may be within C12R in Holes 748B, CllR to C13N in 699A, and around C12R or C13N in Hole 703A, but these Subchrons were not identified by paleomagnetic studies (Hailwood and Clement, 1991a,b; Inokuchi and Heider, 1992).

At Hole 703A, some datums are concentrated within the interval between 703A-12H-2, 60-62 cm and 13H-3, 60-62 cm (102.00-113.00 mbsf). This concentration is influenced by the existence of a hiatus. Hailwood and Clement (1991b) show a mi- nor hiatus just above the horizon of the LAD of Reticulofenestra umbilicus (nannofossil), which was placed between 703A-12H-2, 22-23 cm and 12H-4, 24-25 cm (101.62-104.64 mbsf; Crux, 1991).

The LAD of Amphistylus(?) sp. and FAD of Axo- prunum irregularis are situated just above the bottom

Table 5


Ages of radiolarian datums calibrated by paleomagnetic data (timescales of Berggren et al., 1985, and Cande and Kent, 1992)

NO. Species name 7460 699A 703A 7468 699A 703A

timescale by Berggren et al. (1965) timescale by Cande and Kent (1992)

of A. irregularis Zone in Hole 748B, and these hori- zons are probably included within C12R by Inokuchi and Heider (1992) or within C13N to C13R by Wei et al. (1992). At Hole 699A, the magnetostratigraphic data are too poor to make precise correlation with these radiolarian events.

Lychnocanoma conica Zone (Takemura, 1992) Top: the first appearance of Cyrtocupsellu tetru-

Peru. Reference section. Site 748: 748B-8H-2, 45-47

cm to 8H-3, 45-47 cm (59.05-60.55 mbsf). Site 703: 703A-5H-6, 55-57 cm to 703A-6H-4, 60-62 cm (4 1.45-48.00 mbsf).

Base: the last appearance of Axoprunum irregu- lurk

Reference section. Site 748: 748B-lOH-5, 45-47 cm to lOH-6, 4547 cm (82.55-84.05 mbsf). Site 699: 699A-18H-2, 50-52 cm to 19H-2, 50-52 cm (162.60-172.10 mbsf). Site 703: 703A-7H-1, 50-52 cm to 8H-2,70-72 cm (52.90-64.10 mbsf).

Takemura (1992) defined the top of this zone at the first appearance of Cyrtocapsella tetruperu. At Site 748, C. tetruperu appears in the earliest Miocene just above the Miocene/Oligocene boundary and the base of this species is almost the same as the boundary at Site 703. However, at Site 699, we have not observed this species in earliest Miocene sediments. In this paper, we tentatively define the

top of this zone following the definition of Takemura (1992).

Abelmann (1990,1992) defined the Early Miocene Cycludophoru untiquu Zone of which the base is the first appearance of C. untiquu. At Hole 748B, the base of the C. untiquu Zone is between Samples 748B- lOH-5,45-47 cm and lOH-6,45-47 cm (82.55-84.05 mbsf), which coincides with the FAD of C. tetraperu. Therefore, the top of Lychnocunomu conicu Zone coincides the base of the C. untiquu Zone of Abelmann (1990).

Correlation: The top of this zone is tentatively placed in an interval ranging from the top of paleomagnetic Subchron C6B to the reversed interval between the normal events of Subchron C6AA (A- belmann, 1992). She had calibrated the age of the base of the Cycludophoru untiquu Zone as around 22.6 to 22.2 Ma.

The base of this zone is located within Subchron C9N to ClON at Hole 748B and Subchron C8R or C9N at Hole 699A (Hailwood and Clement, 1991a; Inokuchi and Heider, 1992). At Site 703A, magnetostratigraphic data could not be interpreted at the interval from Sub&on C7N to ClON (approx. 53-66 mbsf) because of the stratigraphic hiatuses within this interval (Hailwood and Clement, 1991b). In this paper, we place the top of this zone in Sub- chron C9N (28.15-29.21 Ma, Berggren et al., 1985) based on the data from Hole 748B.

110 A. Takemura, H.I: Ling/Marine Micropaleontology 30 (1997) 97-116

Remarks: Abelmann ( 1990, 1992) proposed a Late Oligocene to Middle Miocene radiolarian zonation for Antarctic sediments obtained from ODP Legs 113 and 120. Takemura (1992) stated that Abel- mann’s Late Oligocene zonation (Abelmann, 1990) is based on poorly preserved radiolarian faunas. More- over, Abelmann’s species adopted in the Upper Oligo- cene zonation (Abelmann, 1990) show longer ranges. Therefore, we follow Takemura’s zonation for the Up- per Oligocene (Takemura, 1992) in this paper.

55 cm and 119-744A-14H-3, 53-55 cm (118-121 mbsf) at Site 744. This interval was correlated with paleomagnetic Chrons Cl 1 to C12.

5. Southern high-latitude radiolarian distribution

Other biohorizons: The FAD of Cyrtocapsella tetrapera (748B-8H-2, 45-47 cm to 8H-3, 45-47 cm, 59.05-60.55 mbsf; Schlich et al., 1989; Abel- mann, 1992) is situated slightly above the Oligo- cene/Miocene boundary (748B-8H, CC to 9H-1, 40-44 cm, 66.6-67.00 mbsf; Berggren, 1992), and coincides with the top of this zone in Hole 748B. At Hole 703A, however, we could not determine whether the horizon of this datum lay within the Oligocene or Miocene. This datum is also close to the Oligocene/Miocene boundary in Hole 703A.

Lazarus and Caulet (1992) proposed the recon- struction of the geographic extent and circulation of the Southern Ocean throughout the Cenozoic based on proxy indicators such as radiolarian and other microfossil paleobiogeography and sediment distri- butions. They showed that an endemic polar radiolarian fauna had developed during the interval from the Middle Eocene through Oligocene. Combining above proxy indicators, they concluded that the Southern Ocean first appeared in the Late Eocene or Early Oligocene, and that the Polar Front was present for much of the time between the Early Oligocene and the Recent. Less well developed fronts sepa- rating warm and cool waters were proposed in the Late Eocene South Atlantic and Southern Indian Ocean.

The FAD of Vellicucullus altus is included within paleomagnetic Subchron C7R or C7AN in Hole 748B, C6CR or C7N in Hole 699A, and C6CR in Hole 703A (Hailwood and Clement, 1991a,b; Inokuchi and Heider, 1992).

Caulet (1991) recognized many Paleogene radiolarian events from Sites 738 and 744. Although we did not identify all the species he reported, the following two of Caulet’s events (Caulet, 1991) can be correlated with our zonation.

The first appearance of Eucyrtidium antiquum was placed between Samples 119-738B-4H-6, 53-55 cm and 119-738B-4H-7, 53-55 cm (31 to 32.5 mbsf) at Site 738. This horizon is just above the last appearance of the foraminifer Globigerinatheka index which defines the Eocene/Oligocene boundary (between 119-738B-5H-2, 90-95 cm and 119-738B- 5H-3, 90-95 cm, 34.90-36.40 mbsf; Huber, 1991). This horizon is also included within the calcareous nannofossil Reticulofenestra oamaruensis Zone (Wei and Thierstein, 1991). Paleomagnetism, however, was not recorded near the Eocene/Oligocene boundary at Hole 738B (Barron and Larsen et al., 1989; Sakai and Keating, 1991).

Although our observation was focused on biostratigraphically useful species, we attempt here some discussion on the distribution of Paleogene radiolarians in the Antarctic Ocean. The Paleogene radiolarian fauna from the South Atlantic Ocean is quite similar to those from the Kerguelen Plateau, South- em Indian Ocean (Takemura, 1992). Almost all the species described by Takemura (1992) have been observed among the fauna in the southern South At- lantic. Most of zone marker species recognized in the low latitudes (Sanfilippo et al., 1985) have not been seen in the fauna from either the Kerguelen Plateau or southern South Atlantic. On the other hand, most species described by Takemura (1992) occur in these three sites in the southern South Atlantic. The results of the correlation are shown in Fig. 2.

Moreover, the transitions of radiolarian faunas in the Middle Eocene through Oligocene are quite similar between the southern South Atlantic and South- em Indian Ocean. In Leg 120 (Takemura, 1992, Sites 748 and 749), Lychnocanoma conica, Calocyclas sp. A and Cyrtocapsella robusta are few to abundant during the Late Oligocene. The appearance of Vel- licucullus altus is included in this sequence.

The first appearance of Lychnocanoma conica In the Early Oligocene, both Axoprunum irreg- was placed between Samples 119-744A-14H-1, 53- ularis and Eucyrtidium antiquum almost continu-

A. Takemura, H.Y. Ling/Marine Micropaleontology 30 (1997) 97-l 16 111

ously occur. Lychnocanoma conica appears within this sequence and Calocyclas cf. semipolita, including large forms, abundantly occurs in the early Early Oligocene. Eucyrtidium spinosum occurs in the Late Eocene, and Lophocyrtis spp. occurs commonly or abundantly at this time as well. The occurrence of Calocyclas sp. B ranges from late Middle Eocene to Late Eocene. As mentioned above, Theocyrtis tuberosa occurs in the Late Eocene.

Lychnocanoma amphitrite occurs abundantly in the Middle Eocene. Calocyclas sp. C and Sethocyrtis sp. are common to abundant in the lower part of this sequence at Site 748. As mentioned in the previous sections, the biohorizons of most of these species could be correlated between the two oceans.

These facts indicate that the Southern Indian Ocean and the southern South Atlantic surrounding the Antarctic continent were under the influence of the same ocean current from Middle Eocene through Oligocene time. This ocean current was separated from the circulation in the low latitudes as stated by Lazarus and Caulet (1992), and presumably was somewhat cold, or at least cooler than in the low latitudes.

Acknowledgements

We express our sincere thanks to Mr. Amadou of the Department of Geology, Northern Illinois University and Ms. Akiko Nishimura for their help on reading Russian literature. We thank Professors Akira Tokuyama, Toshiharu Nishimura and Yasuhiro Shibue for their kind assistance in this study. We also thank Drs. Jean Pierre Caulet, Brian Huber and David Lazarus for their critical reviews on our manu- script to improve it. This study was supported in part by Grant-in-Aid for Encouragement of Young Scien- tists (A, No. 05740325/‘Iakemura) and Grant-in-Aid for Co-operative Research (A, No. 04304009/Yao) by the Ministry of Education, Science and Culture of Japan.

Appendix A. Species list

Acanthodesmiidae, gen. et sp. indet. (Plate I, 5) Actinomma aff. golownini Petrushevskaya - aff. Actinomma

golownini Petrushevskaya, 1975, pp. 569, plate 2, fig. 16. Amphistylus angelinus (Clark and Campbell) - Chen, 1975,

pp. 453, plate 21, figs. 3-4.

Amphistylus(?) sp. - Takemura, 1992, pp. 741, plate 5, figs. 9-10 (Plate I, 3)

Artostrobus(?) cf. pmtabulatus Petrushevskaya-Takemura, 1992, pp. 745, plate 5, fig. 12; cf. Artostmbus(?) pretabulatus Petrushevskaya, 1975, pp. 580, plate 10, figs. 2-3.

Axoprunum bispiculum (Popofsky) - Takemura, 1992, pp. 741-742, plate 1, figs. l-2.

Axoprunum irregularis Kozlova, 1983 ,pp. 88-89, plate 1, fig. 4; Axoprunum(?) irregularis Takemura, 1992, pp. 742, plate 3, figs. 8-l 1 (Plate I, 2)

Remarks: Although Kozlova’s forms (Kozlova, 1983) have somewhat longer polar spines and are older in geologic age (Paleocene), they resemble earlier Antarctic forms which occur close to the Eocene/Oligocene boundary. We therefore tentatively use A. irregularis in this paper.

Axoprunum pierinae (Clark and Campbell) - Takemura, 1992, pp. 742, plate 6, figs. 3-6 (Plate I, 1)

Botryopyle dictyocephalus Haeckel group - Riedel and San- filippo, 1971, pp. 1602, plate lJ, figs. 21-26, plate 27, figs. 16- 18, plate 3F, figs. 9-12.

Calocyclas cf. semipolha Clark and Campbell-Abelmann, 1990, pp. 697, plate 7, fig. 4 (Plate I, 16)

Calocyclas spp. A - Takemura, 1992, pp. 745, plate 1, figs. 3-4 (Plate I, 15)

Calocyclas sp. B - Takemura, 1992, pp. 745, plate 5, fig. 13 (Plate I, 14)

Calocyclas sp. C - Takemura, 1992, pp. 745, plate 7, fig. 3-4 (Plate. I, 17)

Cyrtocapsella robusta Abelmann, 1990, pp. 696, plate 5, fig. 11 (not 10) (Plate I, 18)

Carpocanistrum spp. - Riedel and Sanfilippo, 1971, pp. 1596, plate lG, figs. l-6 and 8-13, plate 2F. figs. 5-16, plate 3D, figs. 1, 2, 6, 7 and 9.

Ceratocyrtis spp. Clarhrocyclas universa Clark and Campbell, 1942, pp. 86,

plate 7, figs. 8-12, 14-21 and 25. Comutella spp. Corythomelissa horrida Petrushevskaya, 1975, pp. 590, plate

11, figs. 14-15, plate 21, fig. 9. Corythomelissa(?) sp. - Takcmura, 1992, pp. 744, plate 2,

figs. 3-4. Coryrhospyris aff. jubata Gall-Takemura, 1992, pp. 743, plate

3, figs. 3-4 - aff. Corythospyris jubata Gall, 1978, pp. 177- 178, plate 4, figs. 1, 2.4, 5, and 7-17.

Cycladophora bicomis (Popofsky) - Lombari and Lazarus, 1988, pp. 106-114, plate 4, figs. 1-12, plate 5, figs. 1-12.

CycZadophora conica Lombari and Lazarus, 1988, pp. 105- 106, plate 3, figs. t-16.

Cyrtocapsella tetrapera Haeckel, 1887 - Sanfilippo and Riedel, 1970, pp. 453, plate 1, figs. 16-l 8.

Dendrospyris stabilis Goll, 1968, pp. 1422-1423, plate 173, figs. 16-18 and 20.

Dicolocapsa microcephala Haeckel, 1887, pp. 1312, plate 57, fig. 1.

Dictyoprvra mongolfieri (Ehrenberg) - Nigrini, 1977, pp. 250-251, plate 4, fig. 7.

Dictyoprora pirum (Ehrenberg) - Nigrini, 1977, pp. 251, plate 4, fig. 8.

112 A. Takemura, H.Y: Ling/Marine Micropaleontology 30 (1997) 97-116

3 100 pm I


Diplocyclas sp. - Diplocyclas sp. A, Petrushevskaya and Kozlova, 1972, pp. 541, plate 33, figs. 14-16.

Eucyrtidium antiquum Caulet, 1991, pp. 535-536, plate 4, figs. l-2.; Eucyrtidium cheni Takemura, 1992, pp. 746, plate 4, figs. l-4 (Plate I, 9)

Eucyrtidium nishimurae, Takemura and Ling, n. sp. (Plate II, l-6)

Description: Shell cylindrical to spindle-shaped with 4 segments. Cephalis small and subspherical, poreless or with some relict pores. Apical horn conical and usually bladed. The length of the apical horn nearly the same as the height of the cephalis or longer, but not longer than twice that height. Thorax tnm- cate-conical usually with irregularly arranged, subcircular pores. Collar stricture visible. Abdomen barrel-shaped and inflated with distinct lumber stricture. Abdominal pores subcircular and simi- larly sized with hexagonal and longitudinal arrangement or irregular. In some specimens, a spongy meshwork extends from the 4th segment covering the surface of the lower part of abdomen. The 4th segment cylindrical with a thick spongy meshwork of various length. Usually a indistinct partition of the segment is visible in the 4th segment. The height of the 4th segment above this partition nearly the same as that of the abdomen. Stric- ture commonly visible between abdomen and the 4th segment. Aperture open and large at the base of the 4th segment.

Measurements: Length of apical horn, 16-33 pm. Height of primary three segments (cephalis, thorax and abdomen), 88- 115 Km. Length of the 4th segment, 90-192 pm. Width of shell, 88-123 pm. Measured in 24 specimens from Samples 114-702B-5X-2, 50-52 cm and 114-703A-18X-3, 50-52 cm. Type specimens are deposited at the Geoscience Institute, Hyogo University of Teacher Education.

Remarks: This new species is characterized by the possession

of spongy shell at its 4th segment. Although the shape of the primary three segments of this species resembles that of Eucyr- tidium antiquum Caulet and Eucyrtidium spinosum Takemura, the shell structure of the post-abdominal segment is completely different. Although we described this species as Eucyrtidium with four segments, the generic assignment is tentative, and the indistinct partition within the 4th segment may be that between the 4th and the 5th segments.

The species name is given after Miss Akiko Nishimura for her contributions on Mesozoic and Cenozoic radiolarians.

Eucyrtidium spinosum Takemura, 1992, pp. 746, plate 5, figs. 5-8 (Plate I, 10)

Eucyrtidium spp. Eusyriingium jistuligerum (Ehrenberg) - Riedel and Sanfil-

ippo, 1970, pp. 527, plate 8, figs. 8-9. Lamprocyclas matukohe O’Connor, 1994, pp. 334-336, plate

2, figs. 9, 10, 14, 15, plate 4, figs. 6-l 1. Lithomelissa challengerae Chen, 1975, pp. 457, plate 8, fig. 3. Lithomelissa sp. - Takemura, 1992, pp. 744, plate 2, figs.

11-12. Lithomelissa sphaerocephalis Chen, 1975, pp. 458, plate 8,

figs. l-2. Lithomelissa spp. Lithomelissa tricornis Chen, 1975, pp. 458, plate 8, figs. 6-7. Lophoconus titunothericeraos Clark and Campbell, 1942, pp.

89, plate 8, figs. 24-26, 28 and 30-37. Lophocyrtis biaurita (Ehrenberg) - Chen, 1975, pp. 461,

plate 3, fig. 2. Lophocyrtis (Paralampterium) dumitricai Sanfilippo, 1990,

pp. 308, plate III, figs. 7-13 (Plate I, 13) Lophocyrtis (Puralampterium)? longiventer (Chen) - Sanfil-

ippo, 1990, pp. 309-310, plate III, figs. l-5 (Plate I, 12)

Plate I 1. Axoprunum pierinae (Clark and Campbell). Sample 114-703A-17X- 1,40-42 cm. Q25/1 (England Finder Location). 2. Axoprunum irregularis Kozlova. Sample 114-699A-22H-2.49-51 cm. 03112. 3. Amphistylus(?) sp. Sample 114-703A-17X-1,40-42 cm. M19/0. 4. Zygocircus biitschli Haeckel. Sample 114-699A-35X-4, 50-52 cm. K45/0. 5. Acanthodesmiidae, gen. et sp. indet. Sample 114-702B-10X-3, 50-52 cm. K50/0. 6. Vellicucullus altus Abelmann. Sample 114-699A-lOH-2,50-52 cm. N37/3. 7. Lamprocyclas matakohe O’Connor. Sample 114-699A-12H-2,50-52 cm. 018/2. 8. Theocyrtis tuberosa Riedel. Sample 114-703A-17X- 1,40-42 cm. 04712. 9. Eucyrtidium antiquum Caulet. Sample 114-699A-28X-1, 90-92 cm. Q20/0.

10. Eucyrtidium spinosum Takemura. Sample 114-703A-18X-3, 50-52 cm. F25/3. 11. Sethocyrtis sp. Sample 114-702B-10X-3, 50-52 cm. U34/1. 12. Lophocyrtis (Paralampterium)? longiventer (Chen). Sample 114-702B-5X-2, 50-52 cm. F26l3. 13. Lophocyrtis (Parulampterium) dumitricai Sanfilippo. Sample 114702B-9X-2, 50-52 cm. J49/0. 14. Calocyclas sp. B. Sample 114-703A-18X-3, 50-52 cm. L37/0. 15. Calocyclas sp. A. Sample 114-699A-IOH-2, 50-52 cm. L2010. 16. Culocyclus cf. semipolita Clark and Campbell. Sample 114699A-28X-1, 90-92 cm. G38/0. 17. Calocyclas sp. C. Sample 114-702B-9X-2, 50-52 cm. X27/1. 18. Cyrtocapsella robusta Abelmann. Sample 114-699A-12H-2,50-52 cm. L20/0. 19. Theocyrtis diabloensis Clark and Campbell. Sample 114-699A-28X-1,90-92 cm. M46/0. 20. Lychnocanoma conica (Clark and Campbell). Sample 114-699A-12H-2,50-52 cm. N26/2. 21. Lychnocanoma amphitrite Foreman. Sample 114-702B-10X-3, 50-52 cm. U55/0.

A. Takemura, H. E Ling /Marine Micropaleontology 30 (1997) 97-l 16

Plate II 1, 2. Eucyrtidium nishimurae, n. sp. Holotype. HUTE-R-402 1. Sample 114-702B-5X-2, 50-52 cm. K32/1. 3, 4. Eucyrtidium nishimurae, n. sp. Paratype. HUTE-R-4022. Sample 114-702B-5X-2,50-52 cm. N44/0. 5, 6. Eucyrtidium nishimurue, n. sp. Paratype. HUTE-R-4023. Sample 114-702B-5X-2, 50-52 cm. N49/4.

Lophocyrtis (Paralampterium) spp. Remarks: Commonly Lophocyrtis species described by San-

filippo (1990) are broken and difficult to identify. We have counted broken and intermediate forms between L. dumitricai and I?.(?) Iongiventer as L. spp.

Lychnocunoma amphitrife Foreman, 1973, pp. 437, plate 11, fig. 10 (Plate I, 21)

Lychnocunoma cf. babylonis (Clark and Campbell) - Take- mura, 1992, pp. 747, plate 7, fig. 13; cf. Lychnocunoma babylonis (Clark and Campbell) group, Foreman, 1973, pp. 437, plate 1, fig. 17, plate 11, fig. 9.

Lychnocanoma conicu (Clark and Campbell) - Abelmann, 1990, pp. 697, plate 6, fig. 8, plate 7, figs. IA-1B (Plate I. 20)

Lychnocanoma spp. Periphaena decoru Ehrenberg, 1873, pp. 246; Sanfilippo and

Riedel, 1973, pp. 523, plate 8, figs. 8-10, plate 27, figs. 2-5. Periphaena heliasteriscus (Clark and Campbell) - Santil-

ippo and Riedel, 1973, pp. 523, plate 9, figs. l-6, plate 27, figs. 8-9.

Peripyramis spp. Plagoniid, gen. et sp. indet. - Takemura, 1992, pp. 744,

plate 1, fig. 10. Prunopyle haysi Chen, 1975, pp. 454, plate 10, figs. l-3. Prunopyle spp. Prunopyle tetrapila Hays, 1965, pp. 172, plate II, fig. 5. Pterocunium(?) sp. - Chen, 1975, plate 13, fig. 9. Saturn& circularis Haeckel, 1887, pp. 13 1. Sethocyrtis sp. Chen, 1975, pp. 459, plate 1, figs. 4-5:

Takemura, 1992, pp. 747, plate 7, figs. 14-15 (Plate I, 11) Siphocumpe acephala (Ehrenberg) - Nigrini, 1977, pp.

254-255, plate 3, fig. 5. Siphocumpe nodosaria (Haeckel) - Nigrini, 1977, pp. 256-

257, plate 3, fig. 11. Siphocumpe(?) quadrata (Petrushevskaya and Kozlova) -

Nigrini, 1977, pp. 257, plate 3, fig. 12. Spongodiscus spp,

Spongoplegma aff. antarcticurn Haeckel - Takemura, 1992, pp. 742, plate 2, figs. 9-10; aff. Spongoplegma antarcticum Haeckel. 1887, pp. 90-Hays, 1965, pp. 165-167, plate I, fig. 1.

Stylosphaera spp. Theocyrtis diubloensis Clark and Campbell - Caulet, 1991,

pp. 539, plate 4, fig. 13; Theoperid, gen. et spp. indet. - Takemura, 1992, pp. 747, plate 4, fig. 10 (Plate I, 19)

Theocyrtis sp. - Riedel and Sanfilippo, 1978, plate 1, fig. 12.

Theocyrtis tuberosu Riedel, 1959, pp. 298, plate 2, figs. lo- 11; Sanhlippo et al., 1985, pp. 701-702, fig. 32 (Plate I, 8)

Whcucullus altus Abelmann, 1990, pp. 698, plate 8, fig. 6. - Wlicucullus cf. oddgumeri Bjorklund - Takemura, 1992, pp. 744, plate 2, figs. 7-8 (Plate I, 6)

Remarks: Takemura (1992) described this species as kllicu- cullus cf. oa’dgumeri sensu Abelmann (1990). However, these Oligocene forms should be identified as V altus Abelmann judg- ing from the shape of the thorax.

Xiphospira spp. Zygocircus biitschli Haeckel, 1887, pp. 948; Petrushevskaya

and Kozlova, 1972, pp. 534, plate 41, figs. 8-l 1 (Plate I, 4)

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Documents

Eocene and Oligocene radiolarian biostratigraphy from the Southern Ocean: correlation of ODP Legs 114 (Atlantic Ocean) and 120 (Indian Ocean)