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1996 Upper Cretaceous Calcareous Nannofossil Biostratigraphy and Paleoceanography of the Southern Ocean David K. Watkins University of Nebraska-Lincoln, [email protected]

Sherwood W. Wise Jr. Florida State University

James J. Popsichal Florida State University

Jason Crux BP Exploration

Follow this and additional works at: http://digitalcommons.unl.edu/geosciencefacpub Part of the Earth Sciences Commons

Watkins, David K.; Wise, Sherwood W. Jr.; Popsichal, James J.; and Crux, Jason, "Upper Cretaceous Calcareous Nannofossil Biostratigraphy and Paleoceanography of the Southern Ocean" (1996). Papers in the Earth and Atmospheric Sciences. 258. http://digitalcommons.unl.edu/geosciencefacpub/258

This Article is brought to you for free and open access by the Earth and Atmospheric Sciences, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Papers in the Earth and Atmospheric Sciences by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

5.4 Upper Cretaceous calcareous nannofossil biostratigraphy and paleoceanography of the Southern Ocean

David K. Watkins l , Sherwood W. Wise, Jr.2, James J. Pospichal2, Jason Crux3

1Department of Geology, University of Nebraska, Lincoln, NE 68588-0340, USA 2Department of Geology, Florida State University, Tallahassee, Florida 32306, USA 3BP Exploration, 5151 San Felipe, Houston, Texa, USA

ABSTRACT

Nannofossil data from the Naturaliste Plateau from these assemblages, but relatively few «5) (DSDP Legs 26 & 28), Falkland Plateau (DSDP high-latitude endemic species are evident. In gen­ Legs 36 & 71), Maud Rise (ODP Leg 113), North­ eral, these can be characterized as somewhat depau­ east Georgia Rise (ODP Leg 114), and Kerguelen perate low latitude assemblages with the addition of Plateau (ODP Leg 120) yield a set of consistent, a few high latitude species. Biostratigraphical sub­ reliable biohorizons that form the basis of a revised division of this interval is based only on cosmopoli­ calcareous nannofossil zonation for the Southern tan taxa used in more low latitude zonations. A Ocean Upper Cretaceous. Analysis of this zonation substantial disconformity separates the Lower and indicates significant changes in the circum-Antarc­ Upper Campanian throughout the Southern Ocean tic climatic regime during the Campanian and sites drilled to date. A disconformity of similar Maastrichtian that foreshadow the more dramatic biostratigraphical placement and hiatus has also climatic shifts ofthe Palaeogene. Calcareous nanno­ been identified on the Western Australian margin. fossils from the Turonian through the Lower Cam­ Above this disconformity, there is a significant in­ panian of the studied sections are characterized by crease in the number of austral or bipolar species in low diversity assemblages consisting largely ofcos­ the Upper Campanian and Maastrichtian. Evolu­ mopolitan species. Low-latitude taxa are absent tionary radiations within the genera Biscutum and Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

356 Upper Cretaceous calcareous nannofossils of the Southern Ocean

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"""" """'" """", .. ,/ ··iM.'.I ...\:" j::i?- ~.. ~.'....." .....' """.,... ,.,..'•....•. .... :_.. ", ,/l . : . .... """ .,,::.'::::,: .••••..•,.•.•.•.• ,.'.'.,; .,<.>,:. . .. ."::"::;;.::.?: .

Fig. 1. Location of the SOllthern high latitude sites discussed in this study.

Monomarginatus, and in the Cribrosphaerella­ This is most evident in the progressive exclusion of Psyktosphaera-Nephrolithus plexus in the austral Watznaueria bamesae during the middle to late region indicate that the Southern Ocean was Maastrichtian. A poleward migration of W. bame­ ecologically distinct from low latitude areas during sae during the last 500,000 years of the Maas­ the late Campanian and Maastrichtian. The high trichtian suggests a briefpulse ofwarming just prior degree of provinciality evident during this time to the Cretaceous-Tertiary boundary. suggests the development of a (cooler) Southern Ocean surface water mass that was oceanographi­ INTRODUCTION cally distinct from the (warmer) low latitude surface waters. Significant declines in the species richness Upper Cretaceous pelagic sediments were cored of the nannofossil assemblages throughout the first by ocean drilling during the 1970's. It quickly Maastrichtian suggest progressive climatic cooling. became clear that the Upper Cretaceous calcareous Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 357

Northeast Kerguelen Naturaliste Falkland Maud Plateau Plateau Georgia Plateau Rise Rise 747 748 750 258 264 327 511 698 700 689 690

c ctl .-...... c () -- ...... l/l ctl ctl ~

c .-ctl C ctl a. E ctl () ?

.. ~ ....~...... c ~ ctl (f) ?Ps:l ~ Con. .I ...... ~.. =:=~ ~ Tu r. G- b =~=~-G c G­ I ----I .-ctl ---G -- b c fij----I ctl E 0 ? c Q) () ~ .. ..

_-- G z p III 111-- debris chalk biogenic chalk and claystone flows limestone dark marl chert glauconite zeolite pyrite

Fig. 2. Stratigraphic record of the Upper Cretaceous from the SOllthern high-latitude sites considered in this ."itudy. Interval,,, denoted with the symhol "b" to their right are barren of nannofossils. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

(,H (II Q(l

! !.~~. • • i .~ •i. .~ .~ . ~ •• ~ i ~ ~ i '~i ~ l" ~." •• ~ ~ .! ~. ..x ! • 1: I II I" iI i d IliJIIJI~lllltlllijli~llfil,iIIIIIIJIIIIIII~lillllk~~I~III~ljllllljli~III!lli '1:l ~ jj ~~~~~~~~UUOUOOO~~w~~~~ti~~~~~~~~~~~~~~~~O~~~~~~~~~O~~~~~~~~~~~~~~~~~~~SSS~~~NNNN ZonoI...... '1:l 258·5·1 (89-90) A G F R FAFC F F F R RC F F F R A R F R F F F C F R C RR F R F RC F F A R F (ll "'l 1-1. tr,abeculdtus ~8·5-2 (39-otO) A G eRR CAe c F F RFFFRF R F A C R C R F RR F F F FAFCR F R F C C F R • F F ~8-5-2 (j (139-140) A M F F F C F C F F C F F R F CC F R F R F F R C F CRFF F RR F F F R • F C 258-5-3 (89-90) C F F F F RFFR C F C F RRFRFR R F F RR FCRFARA F R F F F C F F • F F R • GC ~ 258-6·1 (139-140) eRR C F F F F RCFFRF F • C R CR C F R F F AR FAR R F RRR C F • R F • F C • G ~ 258-6-2 (89-90) A M C C F F F F RFFFRC F CC F C F RC R F AFFF A R F FFFCF F • F F n 258-6-3 (39-Ml) eM C F R F RFFFRC F • C R F F RR F F FAA A R R F F RFAC R • -(ll C F F •• 258-6-3 (139-1.40) C F F F F RFFRFC F CC F A F F RC F FFFC RRRRC R R • CC o • M C =: 258-6-4 (89·90) C C F F F FRRFF F C F CC RCRC CRR FCFFRFA R R F F F C F • F CR 'JJ T. ecclesiastic 258-6-5 (39-40) eM C F F F F F RFFRFC F CC R F F F F FFFFFFC RRR F F R • CC n 258-6-5 (139-140) CAR C F R F F F F F C F CC R F F C F F FFFFRFA R RR F RC F • CC • M C !. 258-7-1 (89-90) A GCR FRFF F F FFAFC RCCC F CR F F C F FCFFRFA R F R F FFFCFF A AFC F n ~ 258-7-2 (39-40) CAAC C F F F F RC F C R CR F F F R FF FeR RR F RRC F F C F • F C • GC • R "'l 258-7-2 (139-140) F F CC R F CRC F • R C F F RR FFCCRFAR R F R F ? CR F • C F (ll • GC 258-7-3 (89-90) F F F C F R F F RCR F CC F F F F C FFFFRFAR F R F F F C R A. R F C R • GC o 258-9-1 (39--<40) F F F RR FFRFCR F C R R C F F F RR CFCFRFCR RR F F C R F • CC =: • M C 'JJ 258-9-1 (139-140) eM C F R F F F F F F R F C F F CR F F FFFC R F F C F • CC F :: 258-10-1 (89-90) C M C FRFF F R RFRFC F RRCR F F F F F C F C F F CC F R F • F F F F ~ Z. kerguelotnens 258-10-2 (39"'0) eM C C F R F FFFFFRRFR F RR F F FFFF • R F R F RFFCR F • CC F F • R :: 258-10-2 (139-140) F M F F F R F R F F C F R F F F • F R F F R A. RRR F R F RC F • F C F :: 258-11-1 (89-90) eM C F F RRFFRFCRFRFF R F R F F FFFF F R R F F • RCR 258-11-2(39"'0) F P F F R F R F F C F C F FFFC F RR C • F F ~ 258-11-2 (13IH40) CPC F RR R F F CC F F F F RR F F C F R C • C F 258-11-3 (139-140) eM C F R F F R RF FCC C R F R R F FFRFR R CC • F C [!.l. K. Iflagnlr1cTJs 258-12-1 (39"'0) eM R F RR F RR F F C F RCCR F F R F F FCFF F F F C R • F F R t;;' 258-12-1 (139-140) F P F F F FFFFFR RC F R F FFRFR R RR C • CC o ~8-12-2 ...., (89-901 eMF F R CRFFFFFC F R R F F RFFCRFR R F C • F F F ~8-12-3 (39"'0) eM C F F R F F RFFFCC RCR CR F C F F FFRR RRR R F C F • C F ~ 258-12-3 (139-140) eMF F R R FFCFRRC F C RC FFFF RR RR F C • F CR (ll ~8-12-4(89-90) eM C F R F FFCF F CRC RR F R F C R R F R F F F R • F CR ~8-12-5 rFJ (39-.40) eM C CR F F R C CCRCCR • R CFFR F R RRR F F C • C F F o 258-12-5 (139-140) FPC C R R CCR F F C F R F FCFF R RR F C • C F =: 258-12-6 (89-90) F PR F RRRRRRFRCF F F R F F R FCFF F C A. RCF R

Q_ gartnerll ~8-13-1 (119-120) eM C F FRFF RRFRCFR F F F F R CFCFF F F F F CC F • =­ttl 258-13-2 (69-70) RAFFRR F CC F F F F F CCCFFR R R R C C F - • M C • • 258-13-3 (19-20) eMF F F FFRAA CCC R F F F FFRF RR F F A. RFF F 3 ~8-t3-3 (119-120) AM C F C CR FFFC F RR F F F F F F R F C F • C F o 258-13-4 (69-70) eMF C F RR R R C F F F C F R F FFFFR R RRC C • F CRR n 258-14-1 (19·20) B ttl ~ E. turriselrrel 258-14-1 (119-120) F G RC F RR CRFC R F R F F F R F F FRAFRC F RC RR • A R ::

Table 1. Calcareolls nannofossil distribution in the (jpper Cretaceolls of Site 258, Naturaliste Plateau. Only formal (described) taxa arc reported in Table 1. Preservation and abundance designations follow those of Watkins (] 992). Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 359 nannofossils from the Southern Ocean region were without any apparent silification. This lies discon­ distinctly different than those observed at lower formably on Lower Turonian chalk. The base of the latitudes. Many of the taxa encountered had never Upper Cretaceous section consists of Cenomanian been observed at low latitudes, as is evident by the interbedded zeolitic claystone and zeolitic, nanno­ more than twenty new Upper Cretaceous taxa docu­ fossil chalk. mented by Wise & Wind (1977) from Leg 36 on the Drilling at Site 264 recovered 1.7m ofnannofossil Falkland Plateau. Conversely, several of the key chalk from an 8m drilled interval. Bukry (1975) taxa used to subdivide biostratigraphically the Up­ placed this chalk in the Santonian or Lower Cam­ per Cretaceous of low latitudes (e.g., Ceratoli­ panian (his Gartnerago obliquum Zone). Re-exami­ thoides aeuleus, Quadrum trifidum, Quadrum nation of this sequence (Table 2) indicates that sissinghii. and Mieula murus) were absent from Section 264-11-1 contains Upper Campanian chalk. these high latitude assemblages. Wise & Wind This section appears to overlie disconformably Sec­ (1977) applied a low latitude zonation to the Upper tion 264-11-2 ofearly late Campanian age, although Cretaceous of Leg 36 with indifferent success, the absence of one subzone (the R. levis Subzone of yielding only a crude biostratigraphic subdivision. this paper) may be a drilling artifact. It was clear that more data was needed before a coherent zonation could be proposed for the South­ Falkland Plateau: The Upper Cretaceous record ern Ocean Upper Cretaceous. from the Falkland Plateau consists ofsediment from two sites: Site 327 (Leg 36) and Site 511 (Leg 71). Recent drilling by the Ocean Drilling Program Drilling at Site 327 penetrated a 50m section of (ODP) has provided a significant increase in the Upper Campanian through Lower Maastrichtian number and quality of Upper Cretaceous pelagic chalk with beautifully preserved nannofossils. Un­ sediment sections from the Southern Ocean. Com­ fortunately, drilling was discontinuous through this pilation of this new data, coupled with re-examina­ interval. Wise & Wind (1977) named and docu­ tion of Deep Sea Drilling Project (DSDP) material, mented many of the austral species which charac­ allows a re-evaluation of the several tentative zona­ terize this interval. Wind (I979a, b) used this tion schemes that have been proposed for the Upper sequence, in combination with piston cores, to pro­ Cretaceous of the Southern Ocean. Data from five pose the first austral zonation for the late Campanian areas was used in this compilation: Falkland Pla­ and Maastrichtian. The Santonian at Site 327 con­ teau, Maud Rise, Northeast Georgia Rise, Natural­ sists of a thin (6m) unit of zeolitic claystone with iste Plateau, and Kerguelen Plateau (Fig. I). The poorly preserved (dissolved) nannofossil assem­ distribution of Upper Cretaceous sediment in time blages. Two metres of questionably Cenomanian for these areas is illustrated in Fig. 2. claystone lies below the Santonian at this site. The Naturaliste Plateau: Two DSDP holes penetrated assemblages in this Cenomanian(?) sediment are Upper Cretaceous sediment on the Naturaliste Pla­ sparse and poorly preserved. Mixed assemblages teau: Site 258 (Leg 26) and Site 264 (Leg 28). were recovered in a soupy mixture ofsediment from Drilling at Site 258 penetrated approximately 149m Site 330. The Site 330 material is not considered of Cenomanian through Upper Santonian sediment herein because of its inherent lack of stratigraphic (Davies, eta!., 1974). Calcareous nannofossil bios­ integrity. The Upper Cretaceous record at Site 51 I tratigraphy from this section was described briefly is more complete than that at Site 327, although it by Bukry (1974) and in greater detail by Thierstein contains at least four significant breaks in sedimen­ (1974). The nannofossil assemblages from this se­ tation. The upper part of the sequence consists of quence have been re-examined and are presented in approximately 14m of nannofossil chalk overlying Table I. Sections 258-5-1 and 258-5-2 consist of 10m of zeolitic claystone. Wind & Wise (1983) upper Santonian nannofossil chalk with thin inter­ assigned the chalk sequence to the late Campanian beds of silicified chalk. This lies disconformably on to early Maastrichtian, noting that Core 51 1-23 was an Upper Coniacian through Lower Santonian se­ from the lower Reinhardtites levis Zone (early quence (Sections 258-5-3 to 258-11-1) of chalk Maastrichtian) while Core 511-24 was placed in the Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

360 Upper Cretaceous calcareous nannofossils of the Southern Ocean

T. phacelosus Zone (which was assigned to the late 88SfJWBq 'M u.. u (,) c..> !!J8UpBJJS i1 a: LL u.. Campanian, although it is more probably from the BWJed '1\ u. a: early Maastrichtian as well), The nannofossils ofthe 8113!4~BJq!P 1\ a: a: BU6t/:JBB '.., LL LL a: u. underlying sequence (Cenomanian to Upper? Cam­ snsOf8:J8qd"1 LL U LL panian) are discussed in detail in Wise (1983), Wise fJlf1lnu8~'S a: u. LL a: snoJB!q 'S a: (1983) found that the underlying zeolitic claystone (SiBJ 8) 'ds snql!loupnli a: a: a: was barren of nannofossils, but assigned it to the snJOqdol/iUB 'Ii 'JIB 'ds "Ii < U < U SfABf 'I:J LL Biscutum coronum Zone based on stratigraphical SnJOI[dOlfjUB 'Ii U LL LL considerations, This sequence is separated from the WnpY,UI '0 a: a: WnOII/l06 '0 a: a: underlying strata by a significant disconformity !!J8NJ1S 'd a: which includes most of the Upper Campanian, The BSOUpS 'd a: u.. LL. BSpJ81U! 'd 1.1. LL u.. u.. association of this disconformity with the zeolitic 88:JBl8r.J '0 () u.. U u. claystone facies above and below suggests that it is SfIP,/OWlJis 'd a: LL the result of a shallowing of the CCD (Wise, 1983; s~XVynqY'd LL LL a: !!SU,¥J8M 'N u. u.. u. Basov et ai., 1983; Wise, 1988). Underlying the BIBSSn:J8p'W U U U U eltf1:Juoo'W a: disconformity is an extraordinary thickness (137m) SfJlBJOO9p'W a: a: of Lower Campanian zeolitic and/or nannofossil sno!6/8tJ 'W LL !!Xn8,(~ claystone, This sequence continues downwards into '1 U U U S!Su9/O!wrn '1 a: a relatively thinner (33m) Santonian to Upper 1!/Iu6 '1 a: a: Coniacian claystone, A thin (10m) unit of Upper sn:J!J!u6lJW)/ U u.. u. U sn:Jf/US:JS8J:)!q '9 u u.. u u. Turonian claystone is separated from the overlying wnnb!/qo '9 u.. u.. u.. u. sequence by a disconformity, Approximately 11m !!f/BJJ!8S!.JJflJ"3 a: LL a: u. eB¥J06 '3 a: a: of claystone underlies the Turonian, Wise (1983) Sn,IW!X8 "3 LL a: LL found it to be barren of nannofossils, It is dated as snSSIUj ':J a: LL a: !!/8J86Jf1W ':J u. Upper Cenomanian based on its foraminiferal con­ !!6J8qU8JlI8 ':J a: a: a: tent (Basov et ai., 1983), sn:J!uo:J ':J a: a: a: sye611doxJ '::> a: a: Maud Rise: ODP Leg 113 drilled two sites (689 and sn.uBJ6IJf/ ':J a: LL 690) on Maud Rise which recovered Cretaceous !!lJOs,UJf16 ':;) u.. u.. LL snJn:Jsqo ':J LL LL sediment. The sequence at both sites consists of B/B/U9P '8 LL a: a: foraminiferal-nannofossil chalk with intercalated wnuo)oo '8 U LL u.. u.. SUB1SUO:)"B u.. u.. u.. u.. chert. Pospichal & Wise (1990), who analyzed the sn:mM sn:)Jed "V LL LL calcareous nannofossil assemblages from these snsuedx8 sn:JJBd "V LL LL LL snP.U1SUO:J sn:JJed 'v a: sites, noted that preservation was significantly bet­ BIBl/peds'V' u u.. U u.. ter at Site 690, Both sections appear to be continuous sw..JJJO!lqwio 'V a: B1 B.1p8JO/:JO·V' a: (,) u.. u.. sequences, spanning most ofthe Maastrichtian (Fig, Sn}O:JS 'V LL 2), Both sections have good palaeomagnetic records uO!le1lJ9S9Jd ::IE ::IE ::IE ::IE 90uepunqv u u u u which were correlated with the nannofossil succes­ sion by Pospichal & Wise (1990), Northeast Georgia Rise: ODP Leg I 14 drilled two sites (698 and 700) on Northeast Georgia Rise and its lower t1ank (respectively) which recovered Cre­ taceous sediment. The Upper Cretaceous at Site 698 consists of approximately 66m ofMaastrichtian pe­ lagic limestone, Crux (1991) reported poor pres­ ervation of the assemblages from this site, The Upper Cretaceous at Site 700 is more complete than that at Site 698, although preservation in the pelagic Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 361 limestones of Site 700 is still poor. Crux (1991) Coniacian chalk and dark marl separated by a dis­ recognized eight zones in a 110m thick interval of conformity. upper Campanian through Maastrichtian pelagic Tn summary, the Upper Cretaceous sedimentary limestone (Fig. 2). This is underlain by approxi­ record of the Naturaliste, Falkland, and Kerguelen mately 40m of Santonian to Lower Campanian pe­ plateaux and of the Maud and Northeast Georgia lagic limestone. rises is varied and complex. In general, the Upper Kerguelen Plateau: Drilling on the central Ker­ Campanian to Maastrichtian is best represented by guelen Plateau penetrated Upper Cretaceous sedi­ nannofossil-bearing sediments. There is a persistent ment at sites 747, 748, and 750. The calcareous mid-Campanian disconformity throughout the nannofossils from these sites are documented in study area. This disconformity has been linked with Watkins (1992). The sedimentary history of each significant palaeoecological impact on the develop­ ment of Southern Ocean nannofossil assemblages site is quite different (Fig. 2). Upper Campanian to (Watkins et a!., 1989; Watkins, 1992; Huber & Maastrichtian calcareous ooze is intercalated with Watkins, 1992). The Turonian to Lower Campanian volcaniclastic debris flows at Site 747 (Schlich et ofthe Southern Ocean, as represented by these sites, a!., 1989), complicating the sequence and degrading consists of discontinuous sequences of chalk, zeoli­ the stratigraphical value of this section. A thin tic claystone, or glauconitic claystone. The (10m), condensed sequence of chalk and (basal) Cenomanian is poorly represented at these Southern glauconitic chalk contains Lower Campanian, Up­ Ocean sites. per Santonian, and Upper Turonian to Lower Coniacian sediment separated by disconformities. There is some indirect evidence of the existence of UPPER CRETACEOUS CALCAREOUS middle Cenomanian sediment at, or near, Site 750, NANNOFOSSIL ZONATION FOR THE although no nannofossil assemblages of this age SOUTHERN OCEAN have been discovered (Watkins et a!., 1992). Site 748 contains a thick sequence (493m) ofglauconitic Because of the lack of a standard zonation for these austral Upper Cretaceous nannofossil assemblages, biogenic limestones (upper 293m) and glauconitic different zonal schemes have been used for different claystones (lower 200m). The upper glauconitic arcas. These different biostratigraphical schcmes, biogenic limestones are dominated by neritic and their correlation to the zonation proposed macro- and microfauna, but contain small propor­ herein, is shown in Fig. 3. Stratigraphical ranges of tions ofcalcareous nannofossils throughout most of high-latitude taxa from all of the sites has been the unit which allow biostratigraphical subdivision. compiled and analyzed for consistency and reliabil­ The sequence is assigned to the Campanian and ity. This compilation is presented in Fig. 4. Seven Maastrichtian, with most of the Mid-Campanian events based on the first or last appearance of high­ missing at a disconformity near the base of the unit. latitude species have been deemed reliable and are The lower sequence of glauconitic claystone is bar­ used in constructing the new zonation. These events ren of nannofossils and was dated with palyno­ are denoted by horizontal bars at the base or top of morphs (Mohr & Gee, 1992; Watkins et a!', 1992). their ranges in Fig. 4. These are discussed in the The Upper Cretaceous record at Site 750 consists of course of presenting the zonation, below. 273 m of Upper Turonian-Coniacian to Maas­ The Upper Cretaceous nannofossil assemblages trichtian chalk with scattered chert. Most of the from these five areas form the basis for the zonation sequence (l60 m) is Upper Campanian to Maas­ proposed herein (Fig. 5). The zones proposed are trichtian. This thick chalk unit is separated from the based on the distribution of taxa which are common underlying chalk by a significant disconformity enough throughout the Southern Ocean to allow which encompasses the Mid-Campanian. The un­ zonal recognition at all sites. The subzones are based derlying chalk contains Upper Santonian-early on the distribution of taxa which may not occur at Campanian chalk and Upper Turonian-Lower one or more sites. These subzones are useful if the Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

~ C'I Wise, 1988; N Pospichal Stage & Wise, 1990 Crux, 1991 Watkins, 1991 This Study c P. stoveri N. c. daniae N. frequens ro N. frequens C. daniae N. t::: ..... frequens LAD corystus miniporus "0 .c N. corystus N. corystus "0 u LAD B. magnum ~.., .... LAD R. levis ..... B. notaculum (j (J) FAD N. frequens B. magnum .., B. magnum ~ ro G. bicrescenticus ..... ro ~ LAD T. phacelosus rl ~ N. watkinsii ~ M. primus LAD B. coronum 0 P. firthii ::: FAD N. corystus rl'" c FAD B. magnum B. coronum R. parvidentatum ~ LAD A. parcus ;:;- ro B. eoronum ~ B. parea A. p. expansus ""l c LAD E. eximius ~ ro E. eximius 0 R. levis ::: Q. O. eampanensis LAD R. levis E. eximius E B. dentata ::'" ro ::~ () M. G. diabolum :: LAD S. primirivum C. garrisonii 0 fureatus FAD A. p. parcus G. costatum 0' LAD E. flora lis H. trabeculatus ;!l.'" L. Tloraus r:: LAD L. seprenarius [;i L. flora/is ...... FAD L. cayeuxii E. floralis Santo I I L. septenarius ...,0 ..... FAD R. anrhophorus ::r T. ecclesiastica ~ M. decussara [Jl T. eee/esiastiea Z. kerguelenensis 0 Con. J t:::t3nttln::uillt:: :::..... P. fibuliformis B. dissimilis ::r ..,~ K. magnificus :: Tur. K. magnifieus 0 Q. gartnerii rl ~ ~ I :: Ceno. E. turrisseiffe/ii E. turrisseiffelii

Fig. 3. Comparison of calcareous nannofossil zonations for the Upper Cret.aceous of the southern high-latitudes. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 363

sU8nb8JJ N 8f!fUf!P ·0

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SnJOd1U8/d "W

f!jf!qJf!q ·0 SnJSAJO:J N Sn!Jf!UJ8jf!nb "W SnJf!UfP8d "W sowqj8 1

wnu6f!w"8 IfsufJ(jf!M "W 1--....;....--...,...... -'-";' snjo:Js "If wn/oqf!lp ·D ---I wnUOJo:J "8 wn/n:Jf!jou "8

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!!) U) U) E: U) U) U) U) E: :> U) E: E: .::.! :> t:: :> LU <1> :> 0 .::.! '"t:: ~ :> <1> E: ." .::.! ::::: ~ .2 :> !!! ." t:: .::.! Z <1> .~ U) :; ."" .!!) ~ ~ :> t:: 0 :> t:: ~ ~ t:: ~ 0 .<1> -S ~ :> t:: .Q :~ 0 '" o 2 ~ (.:Jo ~ o::~ '" ~ Cll Cll .'!l Cll U) §, U) {'5 0 Cll C\l N 0 0 U) 1;) ~ .Q Q. :> 0 [D .~ .'"Q. Cll U ~ 0 <.) t:: 1':' ::::::; 0.: ci. 0:: ~ U) E: ::> 0.: eli :;::; Cll '" <: .~ lJ) 0 lJ) en eli Q. ~ ui ...j -'<: 0 .Q '" :x: .~ :.: ~ lJ) "i ~ ~ u lJ) ::::: U .~ lJ) ~ E E :::l c: ~ < '0:: o l.l.i ;2 -- --- C ~ Ue!l4:::>PlSeeV\l ue!uedweo "lUes 0 :::::l () f-

Fig. 4. Compilation or stratigraphic ranges or Upper Cretaceous high-latitude species hased on the studied sites. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

364 Upper Cretaceous calcareous nannofossils of the Southern Ocean

Stage Zone Subzone FAD B. sparsus c P. stoveri tU N. frequens FAD P. stoveri Acme .-...... C. daniae ..c miniporus LAD N. corystus u N. corystus .;:: LAD B. magnum ...... B. notaculum (J) B. magnum LAD R. levis tU G. bicrescenticus tU LAD N. watkinsii ~ N. watkinsii LAD B. coronum P. firthii FAD N. corystus c B. coronum R. parvidentatum tU LAD A. parcus c A. p. expansus LAD E. eximius tU R. levis c.. E. eximius FAD R. levis E B. dentata tU LAD M. furcatus () G. diabolum C. garrisonii FAD G. diabolum G. costatum LAD E. floralis H. trabeculatus E. flora lis LAD L. septenarius Santo L. septenarius LAD T. ecclesiastica T. ecclesiastica LAD Z. kerguelenensis z. kerguelenensis Can. FAD L. septenarius P. fibuliformis B. dissimilis FAD M. furcatus K. magnificus Tur. FAD E. eximius Q. gartnerii FAD Q. gartnerii Cena. E. turrisseiffelii FAD E. turriseiffellii Fig. S. Proposed zonation for the Upper Cretaceous of the Southern Ocean. defining taxa are present, but may not be useful in frequens miniporus. Prediscosphaera cretacea, and some areas or in some facies. Nannofossil datums Prediscosphaera stoveri. are correlated to stage boundaries following the Comments: This zone is equal to the Nephrolithus assignments in Erba et al., 1995. frequens Zone as defined by Pospichal & Wise, Nephrolithusfrequens miniporus Zone 1990. It has been renamed to distinguish it from the Definition: The interval from the last appearance Nephrolithusfrequens Zone ofCepek & Hay (1969) datum (LAD) of Biscutum magnum to the Creta­ that is defined using different upper and lower bio­ ceous/Tertiary boundary as defined by the first ap­ horizons. Pospichal & Wise (1990) stated that the pearance datum (FAD) of Biantholithus sparsus LAD of Reinhardtites levis or the FAD of Neph­ (see comment below). rolithusfrequens might be used to approximate the base of this zone. Results from Site 750 have indi­ Age: Late Maastrichtian. cated that there is a significant stratigraphical sepa­ Authors: This paper (see comment below). ration between the LAD of Biscutum magnum and Associated species: Acuturris scoUtS, Arkhangel­ the LAD of R. levis. The FAD of N. frequens has sheila cymb~formis, Biscutum constans, Cri­ been shown to be quite diachronous (Fig. 6; brosphaereila ehrenbergii. Kamptnerius Pospichal & Wise, 1990; Watkins, 1992) and is not magnificus, Nephrolithus frequens. Nephrolithus a reliable biohorizon in the Southern Ocean. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 365

Low Maud Kerguelen Sissingh ~ Latitudes Rise Plateau Zones

z « ...... ~ I ,ELO ..Qa'- N () E a rr: ~- ..... ~ «CI) 1---­ « C1)­ ~ ~ '-:::'N ~a ct:_'a

Fig. 6. Idealized latitudinal and stratigraphic distrihution or Nephrofithu,\ji-cque!1s and Reinlwrdlites levis and their corresponding biozones. Modified after Pospichal & Wise (1990).

This zone is divided into three subzones: the Crux, 199]) and Hole 750A (Kerguelen Plateau; Prediscosphaera stoveri Acme Subzone, Cri­ Watkins, 1992). brosphaerella daniae Subzone. and Nephrolithus Reference Section: OOP Samples 750A-15R-3. corystus Subzone. 90-91cm to 750A-17R-2, 20-2Icm; 350.0-367.0 Reference Section: OOP Samples 750A-15R-3. mbsf, Central Kerguelen Plateau. 90-91cm to 750A-19R-2, 114cm; 350.0-387.35 Cribrosphaerella daniae Subzone mbsf, Central Kerguelen Plateau. Definition: The interval from the LAO of Neph­ Prediscosphaera stoveri Acme Subzone rolithus corystus to the base of the acme of Predis­ Definition: The interval from the base of the acme cosphaera stoveri. of Prediscosphaera stoveri to the FAO of Bian­ Age: Late Maastrichtian. tholithus sparsus. Authors: Pospichal & Wise (1990) as emended in Age: Late Maastrichtian. this paper. Authors: This paper. Associated species: As above. Associated species: As above. Comments: Wind (1979a) proposed the C. daniae Comments: Pospichal (1989) first noted the very Zone for the interval from the LAO of B. magnum high abundance of P. stoveri in the uppermost to the Cretaceous/Tertiary boundary (equal to the Maastrichtian sediments of Southern Ocean OOP Nephrolithus frequens miniporus Zone as defined sites 690 (Maud Rise) and 752 (Broken Ridge). herein). Pospichal & Wise (1990) used the name for Similar, high abundances of this taxon have been their subzone defined as the interval from the LAD noted from Hole 700B (Northeast Georgia Rise; of N. corystus to the Cretaceous/Tertiary boundary. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

366 Upper Cretaceous calcareous nannofossils of the Southern Ocean

We have further restricted this subzone to exclude Associated species: As above. that interval characterized by the acme of Predis­ Comments: This subzone is generally thin where cosphaera stoveri. present. It is represented by only a single sample on Reference Section: ODP Samples 750A-17R-2, Maud Rise (Sample 690C-18X-5, 36-38cm; l17-118cm to 750A-19R-2, 114-ll5cm; 368.0­ Pospichal & Wise, 1990) and at Northeast Georgia 387.4 mbsf, Central Kerguelen Plateau. Rise (Sample 700B-39R-2, 32-33 cm; Crux, 1991) Nephrolithus corystus Subzone and by less that 7 metres at its thickest locality (Site Definition: The interval from the LAD of Biscutum 750, Kerguelen Plateau). At other Southern Ocean magnum to the LAD of Nephrolithus corystus. sites, the LAD of R. levis and B. magnum appear to Age: Late Maastrichtian. be synchronous, although this may be an artifact of Authors: Pospichal & Wise (1990). sample spacing. Associated species: As above with the addition of Reference Section: ODP Samples 750A-19R-3, Nephrolithus corystus. 10-12cm to 750A-20R-I, 20-2Icm; 387.8-394.5 Comments: see comments for B. magnum Zone, mbsf; central Kerguelen Plateau. below. Glaukolithus bicrescenticus Subzone Reference Section: ODP Samples 690C-18X-2, Definition: The interval from the LAD ofNeocrepi­ 127-129cm to 690C-18X-5, 36-38cm; 274.17 ­ dolithus watkinsii to the LAD ofReinhardtites levis. 277.76 mbsf, Maud Rise. Age: Mid-Maastrichtian. Biscutum magnum Zone Authors: This paper. Definition: The interval from the LAD ofNeocrepi­ Associated species: As above with Reinhardtites dolithus watkinsii to the LAD ofBiscutum magnum. levis. Age: Mid-Maastrichtian. Comments: Nephrolithusfrequens has its first oc­ Authors: Wind (1979a, b) as emended in this paper. currence in this zone on Kerguelen Plateau (Wat­ Associated species: Acuturris scotus, Arkhangel­ kins, 1992). skiella specillata, Biscutum constans, B. magnum, Reference Section: ODP Samples 690C-18X-CC Cribro.\phaerella daniae, C. ehrenbergii, Glauk­ to 690C-19X-6, 28-30cm; 281.1-288.9 mbsf, Maud olithus bicrescenticus, Kamptnerius magn~ficus, Rise. Lithraphidites carniolensis, Lucianorhabdus Neocrepidolithus watkinsii Zone cayeuxii, Micula decussata, Nephrolithus corystus, Definition: The interval from the LAD of Biscutum Nephrolithus frequens, Prediscosphaera cretacea, coronum to the LAD ofNeocrepidolithus watkinsii. P. stoveri, Repagulum parvidentatum. Age: Early Maastrichtian. Comments: Wind (1979a, b) defined this zone as Authors: Crux (1991) as emended in this paper. the interval from the LAD of Biscutum coronum to Associated species: Ahmuellerella octoradiata, the LAD of B. magnum. This zone has been re­ Acuturris scoUtS, Arkhangelskiella specillata, Bis­ stricted herein by retaining the upper biohorizon but cutum constans, B. magnum, Cribrosphaerella redefining the lower limit based on the LAD of N. daniae, C. ehrenbergii, Glaukolithus bicrescen­ watkinsii. Nephrolithusfrequens has its FAD at or ticus, Kamptnerius magnificus, Lithraphidites near the top of this zone, depending on the specific carniolensis, Lucianorhabdus cayeuxii, Micula locality. decussata, Nephrolithus corystus, Prediscosphaera Reference Section: ODP Samples 690C-18X-5, cretacea, P. stoveri, Repaglllum parvidentatum. 36-38cm to 690C-19X-6, 28-30cm; 277.8-288.9 Comments: Crux (1991) defined the Monomargi­ mbsf, Maud Rise. natus primus Zone based on the interval from the Biscutum notaculum Subzone LAD ofBroinsonia parca to the LAD ofMonomar­ Definition: The interval from the LAD of Rein­ ginatlls primus (Crux, 1991) [ = Neocrepidolithus hardtites levis to the LAD of Biscutum magnum. watkinsii (Pospichal & Wise, 1990)]. We have rede­ Age: Mid-Maastrichtian. fined this zone by changing the lower boundary to the Authors: This paper. LAD of B. coronllm. This significantly shortens this Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 367 zone. We have renamed the zone after N. watkinsii Definition: The interval from the LAD of Aspi­ Pospichal & Wise, 1990, which has priority over the dolithus parcus to the FAD of Nephrolithus corys­ junior synonym M. primus Crux (1991). tus. Reference Section: ODP Samples 690C-20X-I, Age: Late Campanian. 30-32cm to 690C-20X-I, 133-135cm; 291.1-292.2 Authors: This paper. mbsf; Maud Rise. Associated species: As for the zone. Watznaueria Biscutum coronum Zone barnesae often has its last consistent common oc­ Definition: The interval from the LAD of Eiffel­ currence (in the Southern Ocean) in this subzone. litlnlc~ eximius to the LAD of Biscutum eoronum. Comments: See comments for underlying A. par­ Age: Late Campanian to early Maastrichtian. eus expansus Subzone. Authors: Wind (1979a) as emended in this paper. Reference Section: OOP Samples 750A-24-CC to 750B-6W-1,0-1 cm; 452.3-488.5 mbsf; central Ker­ Associated species: Ahmuellerella oetoradiata, guelen Plateau. Arkhangelskiella specillata, Biseutum constans, B. magnum, B. coronum, Cribrosphaerella daniae, C. Aspidolithus parcus expansus Subzone ehrenbergii, Glaukolithus bicrescentieus, Kampt­ Definition: The interval from the LAD of Eiflel­ nerius magnijieus, Lithraphidites carniolensis, Lu­ lithus eximius to the LAD of Aspidolithus pare'us. cianorhabdus eayeuxii, Mieula deeussata, Age: Late Campanian. Prediseosphaera cretaeea, P. stoveri, Reinhardtites Authors: This paper. levis, Repagulum parvidentatum, Tranolithus Associated species: As for the zone with A. pareus phaeelosus. and W. barnesae. Comments: Wind (1979a) originally defined this Comments: Both Aspidolithus pareus pareus and zone as the total range of B. coronum. Wise (1983) A. parcus eonstrietus are rare in the Southern Ocean. modified the definition to use either the FAD of B. In general, the top of this subzone is placed at the eoronum or the LAD of Marthasteritesfureatus as LAD of Aspidolithus parcus expansus. This datum the base of the zone. We have restricted the zone by is used at the subzonal level because it is often limiting its lower boundary to the LAD of E. exi­ difficult to differentiate Aspidolithus parcus expan­ mius. This zone is thicker and probably more com­ sus from Arkhangelskiella speeillata in poorly pre­ plete at Site 750 than at the reference section (Site served material without the use of the SEM. 747). At the former site, however, the zone includes Reference Section: ODP Samples 747A-25X-3, sediment recovered in washed cores, making its 114-115cm to 747C-7R-1, 66-67cm; 231.7-262.2 stratigraphical integrity questionable. mbsf; central Kerguelen Plateau. Reference Section: ODP Samples 747A-24X-I, Eiffellithus eximius Zone 114-116cm to 747C-7R-l, 66-67cm; 219.2-262.2 Definition: The interval from the LAD ofMarthas­ mbsf; central Kerguelen Plateau. terites furcatus to the LAD of Eiffellithus eximius. Psyktosphaera firthii Subzone Age: Late early Campanian to early late Campanian. Authors: This paper. Definition: The interval from the FAD of Neph­ Associated species: Ahmuellerella oetoradiata, rolithus eorystus to the LAD ofBiseutum eoronum. Arkhangelskiella specillata, Biseutum constans, B. Age: Late Campanian. eoronum, C. ehrenbergii, Gartnerago obliquum, Authors: This paper. Karnptnerius magnificus, Lithraphidites carniolen­ Associated species: As above with N. eorystus. sis, Lucianorhabdus cayeuxii, Minda deeussata, Comments: This interval is also recognized on the Prediseosphaera eretaeea, P. spinosa, Rein­ Kerguelen Plateau (Site 750; Watkins, 1992). hardtites anthophorus, Repagulum parvidentatum, Reference Section: OOP Samples 690C-20X-2, Tranolithus phaeelosus, Watznaueria barnesae. 28-30cm to 690C-2IX-4, 8-lOcm; 292.6-305.0 Comments: To date, there is no drilled section mbsf, Maud Rise. within the Southern Ocean which preserves the true Repagulum parvidentatum Subzone LAD of M. furcatus. This biohorizon apparently Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

368 Upper Cretaceous calcareous nannofossils of the Southern Ocean occurred during an hiatus represented by the perva­ cianorhabdus cayeuxii, Micula deeussata, Predis­ sive mid-Campanian disconformity (Watkins et aI., cosphaera eretacea, P. spin1Jsa, Reinhardtites an­ 1989; Watkins, 1992). This disconformity is dis­ thophorus, Repagulum parvidentatum, cussed in detail elsewhere in this paper. Seribiscutum primitivum, Tranolithus phaeelosus, Reference Section: ODP Samples 747C-7R-I, Watznaueria barnesae. 115-116cm to 747C-9R-CC, 6-7cm; 262.7-282.2 Comments: Wise (1983) recognized this interval as mbsf; central Kerguelen Plateau. his Marthasteritesfitrcatus Zone. This same name Reinhardtites levis Subzone was used by Cepek & Hay (1969) to denote the Definition: The interval from the FAD of Rein­ interval from the FAD ofM.furcatus to the FAD of hardtites levis to the LAD of E{ffellithus eximius. Minda deeussata. This name has been subsequently Age: Late Campanian. used by several workers (e.g. Sissingh, 1977) to Authors: This paper. denote this early Coniacian interval. In order to Associated species: As above with R. levis. avoid confusion, we have changed the name of the Comments: The FAD of R. levis is used as a early Campanian Southern Ocean zone to the C. subzonal indicator because of the difficulty in dif­ garrisonii Zone. ferentiating the evolutionary divergence of early R. The top of this zone has not been recovered in levis from its ancestor species, Reinhardtites antho­ nannofossil-bearing sediments anywhere within the phorus, in poorly preserved assemblages. Southern Ocean. At the type section of this zone Reference Section: ODP Samples 747C-7R-I, (Site 511, Falkland Plateau), the top of the zone 115-116cm to 747C-9R-I, 111-112cm; 262.7­ grades into barren zeolitic claystones. At other lo­ 281.6 mbsf; central Kerguelen Plateau. calities (Northeast Georgia Rise, Kerguelen Pla­ Broinsonia dentata Subzone teau), this zone is abruptly terminated by a Definition: The interval from the LAD of Marthas­ disconformity well below the top of the zone. The teritesfilreatus to the FAD of Reinhardtites levis. upper boundary marker species, M.fureatus, is not Age: Early Campanian. consistently present in any of the Southern Ocean Authors: This paper. sections drilled to date. It occurs sporadically in Associated species: As for the zone. samples from Site 511, but is relatively common Comments: The base of this subzone is not pre­ when it is present (Wise, 1983). It is apparently served in any of the currently available Southern absent (or very rare) from the carbonate-rich sec­ Ocean sections because ofthe ubiquitous mid-Cam­ tions on Northeast Georgia Rise (Hole 700B, Crux, panian disconformity. This subzone is named for 1991) and Kerguelen Plateau (Holes 747C and Broinsonia dentata, a common species in assem­ 750B, Watkins, 1992). Wise (as cited in Watkins, blages of this age. 1992) has suggested that the abundance of this spe­ Reference Section: ODP Samples 747C-9R-2, 6­ cies in this zone was probably very low, and it is 7cm to 747C-9R-CC, 6-7cm; 282.0-282.2 mbsf, only conspicuous when concentrated by dissolution. central Kerguelen Plateau. Reference Section: DSDP Samples 511-28-2, 115­ Chiastozygus garrisonii Zone 116cm to 511-42-5, 23-24cm; 226-363 mbsf, Falk­ Definition: The interval from the LAD of land Plateau. Eprolithus floralis to the LAD of Marthasterites Gephyrobiscutum diabolum Subzone filreatus. Definition: The interval from the FAD of Gephyro­ Age: Early Campanian. hiseutum diaholwn to the LAD of Marthasterites Authors: Wise (1983) as emended in this paper. furcatus. Associated species: Ahmuellerella oetoradiata, Age: Early Campanian. Arkhangelskiella speciflata, Biscutum eonstans, B. Authors: Wise (1988). coronum, Broinsonia dentata, Crihrosphaerella Associated species: As above with G. diabolum. ehrenhergii, Gartnerago obliquum, Kamptnerius Comments: This subzone has onl y been recognized magn{fieus, Lithraphidites earniolensis, Lu- at the type locality (Falkland Plateau). It is probably Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 369 absent from others areas because of non-deposition Subzone and the lower Seribiscutum primitivum associated with the mid-Campanian disconformity. Subzone. It is possible, however, that Gephyrobiscutum di­ We have emended this zone by designating a new abolum is a form endemic to the Falkland Plateau reference section. The original Falkland Plateau sec­ area. The species G. diabolum is common to highly tion of Wise (1983; Samples 511-43-1, 35cm to abundant (100 specimens per field of view at 1000X 511-45-3, IOOcm; 366-389 m) contains Lithastrinus magnification) throughout most of this subzone septenarius in its uppermost sample. Subsequent (Wise, 1983). It seems to disappear in the upper 5 work has shown that this section lies wholly within metres of the type section, although this may be an the lower S. primitivum Subzone. The new Ker­ artifact of poor preservation. guelen Plateau reference section is stratigraphically Reference Section: DSDP Samples 5 11-28-2, 115­ more complete, albeit thinner, than the Falkland 116cm to 511-41-1, 144-145cm; 226-348 mbsf, Plateau section. Falkland Plateau. Reference Section: ODP Samples 747C-9R-CC, Gartnerago costatum Subzone 16-17cm to 747C-IOR-I, 40-4Icm; 282.3-290.4 Definition: The interval from the LAD of mbsf; central Kerguelen Plateau. Eprolithusfloralis to the FAD of Gephyrobiscutum Helicolithus trabeculatus Subzone diabolum. Definition: The interval from the LAD of Lithas­ Age: Early Campanian. trinus septenarius to the LAD ofEprolithusfloralis. Authors: Wise (1988). Age: Late Santonian. Associated species: As for zone. Authors: This paper. Comments: Common to abundant Helicolithus tra­ Associated species: As above. beeulatus often associated with the base of this Comments: Common to abundant He!icolithus tra­ subzone. beculatus are often associated with the top of this Reference Section: DSDP Samples 511-41-2, 24­ zone. This subzone is represented in Sections 258­ 25cm to 511-42-5, 23-24cm; 349-363 mbsf, Falk­ 5-1 and 258-5-2 on Naturaliste Plateau. land Plateau. Reference Section: ODP Samples 747C-9R-CC. Eprolithus floralis Zone 16-17cm to 747C-IOR-I, 1O-llcm; 282.3-290.1 Definition: The interval from the LAD of Thierste­ mbsf; central Kerguelen Plateau. inia eeclesiastiea to the LAD ofEprolithusf/oralis. Lithastrinus septenarius Subzone Age: Late Santonian. Definition: The interval from the LAD of Thierste­ Authors: Wise (1983) as emended in this paper (see inia ecclesiastica to the LAD of Lithastrinus sep­ comments). tenarius. Age: Late Santonian. Associated species: Ahmuellerella oetoradiata, Biseutum eonstans, Broinsonia dentata, Cretarhab­ Authors: This paper. dus umicus, Cribrosphaerella ehrenbergii, Eiffel­ Associated species: As for the zone with Lithas­ lithus eximius, E. turriseiffelii, Eprolithus floralis, trinus septenarius. Gartnerago eonfossus, G. costatum, Kamptnerius Comments: This subzone is represented by ap­ magnificus, Lithraphidites earniolensis, Lu­ proximately 23m of section at Site 5 II (Falkland eianorhabdus cayeuxii, Micula eoncava, M. deCLls­ Plateau). This section was the original type section sata, Prediseosphaera eretaeea, P. spinosa, for the Lithastrinus floralis Zone of Wise (1983). Quadrum gartnerii, Reinhardtites anthophorus, Re­ Correlation with the sections from central Ker­ pagulum parvidentatum, Seribiseutum primitivum, guelen Plateau indicate the absence of the upper (H. Tranolithus phaee!osus, Watznaueria bamesae. trabeeulatus) subzone at Site 51 I. Comments: The stratigraphical range of Lithas­ Reference Section: ODP Sample 747C-I OR-I, 40­ trinus septenarius is used to divide this zone into 4lcm; 290.4 mbsf; central Kerguelen Plateau. two subzones: the upper Helieolithus trabeeulatus Thiersteinia ecclesiastica Zone Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

370 Upper Cretaceous calcareous nannofossils of the Southern Ocean

Definition: The interval from the LAD of Garlnerago confossus, G. coslatum, Kamplnerius Zeugrhabdotus kerguelenensis to the LAD ofThier­ magniflcus, Lithraphidiles carniolensis, Predis­ steinia ecclesiastica. cosphaera cretacea, P. spinosa, Quadrum gart­ Age: Early late Coniacian to early late Santonian. nerii, Reinhardtites anthophorus, Repagulum Authors: Wise (1983) as emended in this paper. parvidentatum, Seribiscutum primitivum, Thierste­ Associated species: Ahmuellerella octoradiata, inia ecclesiastica, Tranolithus phacelosus, Biscutum constans, Broinsonia dentata, Cretarhab­ Walznaueria barnesae. dus amicus, Cribrosphaerella ehrenbergii, Eiffel­ Comments: Perch-Nielsen (1979) proposed Eiffel­ lithus eximius, E. turriseiffelii, Eprolithus floralis, lilhus eximius as an alternate lower biohorizon for Gartnerago conlossus, G. costatum, Kamptnerius the Lucianorhabdus male{ormis Zone (CC 12) of magnificus, Lithastrinus septenarius, Lithraphidites Sissingh (1977). Assuming the synchroneity of the carniolensis, Marthasterites jilrcatus, M. deC/Is­ first appearances of L. male{ormis and E. eximius is sata, Prediscosphaera cretacea, P. spinosa, Quad­ valid. our P. flbuli{ormis zone is equal to the L. rum gartnerii, Reinhardtites anthophorus, male{ormis Zone of Sissingh (1977). Our zone is Repagulum parvidentatum, Seribiscutum primiti­ named for P.fibuliformis, a relatively common spe­ vum, Thiersteinia ecclesiastica, Tranolithus cies in assemblages of this zone. This zone is repre­ phacelosus, Watznaueria barnesae. sented in four of the study sites: 258 (Naturaliste Comments: Wise (1983) defined this zone as the Plateau), 511 (Falkland Plateau). and 747C and interval from the FAD ofMarthasteritesfiacatus to 750B (central Kerguelen Plateau). The base of the the LAD of T. ecclesiastica, yielding a zone which zone (i.e. FAD of E. eximius) is truncated by li­ spanned the Coniacian through lower upper San­ thologic changes at the Falkland and Kerguelen tonian. We have restricted this zone by redefining sites. but apparently preserved on Naturaliste Pla­ the lower boundary as the LAD of Zeugrhabdotus teau. This zone is divided into three subzones based kerguelenensis. The LAD or Z. kerguelenensis lies on the FAD of M.fianllus and L. seplenarius. The within Im below the FAD of Micttla decussata. a three subzones are all present at only one site (747). widely recognized cosmopolitan species. The where they are each represented by single pieces of gradualistic evolution of M. decussata. accompa­ sediment. nied by numerous transitional specimens, often Reference Section: ODP Samples 747C-I OR-I. 50­ makes its first occurrence difficult to precisely 51cm to 747C-IOR-CC: 290.5-295.1 mbsf. central place. This is especially true in expanded sections Kerguelen Plateau. (such as at Naturaliste Plateau) or where preserva­ Zeugrhabdotus kerguelenensis Subzone tion is poor. Zeugrhabdotus kerguelenensis. on the Definition: The interval from the FAD of Lithas­ other hand. is a very distinctive taxa that is easily trinus septenarius to the LAD of Zeugrhabdotus recognized despite poor preservation. kerguelenensis. Reference Section: DSDP Samples 258-5-3. 89­ Age: Mid-Coniacian. 90cm to 258-9-1. 39-40cm: 126.9-180.9 mbsf, Authors: This paper. Naturaliste Plateau. Associated species: As above with L. septenarius Placozygus fibuliformis Zone and Z. kerguelenensis. Definition: The interval from the FAD of Eif{el­ Comments: This subzone has been identified from lit/w,I' eximius to the LAD of Zeugrhabdotus ker­ the central Kerguelen Plateau, where it occurs in guelenensis. both Holes 747C and 750B. and from the Naturaliste Age: Late Turonian to early late Coniacian. Plateau. The subzone is thicker in Hole 750B (Core Authors: This paper. II W-1.0-1 em to II W-2, 6-8cm: 1.58m), but occurs Associated species: Ahmuellerella octoradiata, in a washed core. This subzone is significantly Bisculum nmstons. Broinsonia dentata, Crelarhab­ thicker (34.1 m) on the Naturaliste Plateau. where it dus conicus. Cribrosphaerella ehrenbergii, E!f{el­ spans Samples 258-9-1, 139-140cm to 258-11-1, lithus eximius, E. turriseitfelii, Eprolithus floralis, 89-90cm. Itmay be possible to further subdivide this Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 371 interval by using the total range of Z. kerguelenen­ intercisa, Prediscosphaera spinosa, Tranolithus sis, which is apparently restricted to the upper part phacelosus, Watznaueria bamesae. of this subzone. In addition, Vekshinella aachena Comments: This zone is poorly represented in the has its first appearence in this zone. Southern Ocean, with only thin sequences ofnanno­ Reference Section: ODP Sample 747C-IOR-I, 50­ fossil-bearing sediments at Sites 258 and 511 recov­ 51 em, central Kerguelen Plateau. ered to date. Biseutum dissimilis Subzone Reference Section: DSDP Samples 258-12-3, 139­ Definition: The interval from the FAD ofMarthas­ 140 em to 258-13-4, 69-70cm; Naturaliste Plateau. tcrites furcatus to the FAD of Lithastrinus sep­ Eiffellithus turriseiffelii Zone tenarius. Definition: The interval from the FAD of Eiffel­ Age: Early Coniacian. lithus turriseiffelii to the FAD of Quadrum gart­ Authors: This paper. ner/I. Associated species: As above with Marthasterites Age: Late Albian to Cenomanian. furcatus. Authors: Wise (1983) as emended here. Comments: This subzone is either absent or less Associated species: Braarudosphaera africana, than 1m thick at Site 258. Braarudosphaera bigelowii, Cretarhabdus Cfmicus, Reference Section: ODP Sample 747C-I OR-I, £. turriseijfelii, Eprolithus floralis, Lithraphidites 147-148cm, central Kerguelen Plateau. camiolensis, Manivitella pemmatoidea, Predis­ Kamptnerius magnifieus Subzone cosphaera cretacea, Seribiscutum primitivum, Tra­ Definition: The interval from the FAD of Eijfel­ nolithus phacelosus, Watznaueria bamesae. lithus eximius to the FAD of Marthasteritesfim'a­ Comments: The Cenomanian record of the South­ tus. ern Ocean is poorly represented in the drilling to Age: Late Turonian to early Coniacian. date. We have adopted this zone directly from Wise Authors: This paper. (1983) with the understanding that future recovery Associated species: As for the zone. of well-preserved Cenomanian-Turonian sections Comments: This subzone is apparently represented may significantly alter this part of the zonation. by a 10 m section (Samples 511-47-1, 40-41 em to Based on the few samples available, it appears likely 511-48-1, 40-41 em; 404-414 mbsf) on the Falkland that the FAD of Ahmuellerella octoradiata, the Plateau. On Naturaliste Plateau it spans the interval FAD of Lithastrinus moratus, and the LAD of Mi­ from Section 258-11-2 to Sample 258-12-3, 39­ crostaurus chiastius will be useful Cenomanian 40cm. The subzone is named for K. magnijicus, a datums in the Southern Ocean. species which commonly occurs in this subzone in Reference Section: DSDP Samples 327A-14-6, 6­ the Southern Ocean. 7cm to 327A-14-CC; 154-156 mbsf; Falkland Pla­ Reference Section: ODP Sample 747C-IOR-CC, teau. central Kerguelen Plateau. Quadrum gartnerii Zone DISCUSSION Definition: The interval from the FAD ofQuadrum gartnerii to the FAD of E{ffellithus eximius. The Southern Ocean zonation, as presented above, Age: Early Turonian. is based on data from the stratigraphical records of Authors: Cepek & Hay (1969). currently available sites. The stratigraphy and drill­ Associated species: Ahmuellerella octoradiata, ing recovery of these sites impose limitations on the Biscutum constans, Broinsonia douata, Chiastozy­ biostratigraphical resolution ofthe zonation. In gen­ gus bifarius, Cribrosphaerella ehrenbergii, E{ffel­ eral, resolution and reliability are best in the upper lithus turriseijfelii, Eprolithusfloralis, Gartnerago part and worst in the lowest part of the zonation. It obliquum, Kamptnerius magnificus (.1'.1.), Lithastrinus is convenient to discuss the zonation in terms of moratus, Lithraphidites camiolensis, Prediscosphaera three intervals: Cenomanian, Turonian to Lower Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

372 Upper Cretaceous calcareous nannofossils of the Southern Ocean

Campanian, and Upper Campanian to Maas­ formities are most prevalent in the mid-Coniacian trichtian. and Lower Santonian (Fig. 2). Cenomanian: Cenomanian sediments were recov­ Nannofossil abundance and preservation varies ered from four ofthe study sites: 258,327,511,748. significantly amongst the sites. Combination ofdata The sediment at sites 511 and 748 consists of from all seven sites, however, yields a good indica­ claystone and glauconitic claystone, respectively, tion of the nature of Southern Ocean nannofossils which is barren of nannofossils (Fig. 2). Foraminif­ for this time interval. The nannofossil assemblages eral and palynological evidence suggests that some can be characterized as a subset of coeval low lati­ middle Cenomanian sediment was penetrated at site tude assemblages with the addition of a few bipolar 750, although no nannofossils of this age were ob­ or austral taxa. Most of the marker taxa used in this served (Watkins et ai., 1992). Thus, the nannofossil part of the zonation (i.e. E. eximius, M. furcatus, L. record used for this interval consists solely of that septenarius, M. decussata, and E. floralis) are those from DSDP sites 258 and 327. The Cenomanian at used in low latitude zonations such as Perch-Nielsen Site 327 consists of approximately two metres of (1985). Only three ofthe biohorizons used (the LAD greenish-gray, clayey micritic ooze with common of Z. kerguelenensis, the LAD of T. ecc!esiastica, Inoceramus fragments. The nannofossil assem­ and the FAD of G. diabolum) are based on austral blages are sparse and generally poorly preserved. In taxa. This is significant for two reasons. First, the fact, the Cenomanian date was derived from large degree of overlap between the low latitude and foraminifera (Sliter, 1977) because the nannofossil austral zonations allows direct correlation and com­ assemblages were not age-diagnostic (Wise & parison of the two areas. Secondly, it indicates the Wind, 1977). Wise (1983, 1988) used the presence relatively low degree ofprovincialism that generally of Eitfellithus turriseitfelii and the absence of characterizes the nannofossil assemblages during Kamptnerius magniticus in this interval to denote this interval. This is in marked contrast to the high the E. turriseitfelii Zone (upper Albian to upper degree of endemism that characterizes the Maas­ Turonian in Wise 1983, 1988), but further subdivi­ trichtian of the Southern Ocean. sion was not possible given the poor nature of the Upper Campanian - Maastrichtian: The Upper assemblages. The Cenomanian from Site 258 is Campanian to Maastrichtian interval was recovered similarly thin (1.5m) and is interbedded with non­ from ten of the study sites including all five oceanic calcareous zeolitic claystone. Nannofossil assem­ plateaus. The record for this interval is best from the blages from this interval contain Microstaurus Maud Rise and, to a lesser degree, the Kerguelen chiastius and Lithraphidites acutus, placing them Plateau. The records from the other plateaux are firmly in the lower part of the Microrhabdulus either poorly preserved (Northeast Georgia Rise) or decoratus Zone (middle Cenomanian) of Sissingh fragmentary (Naturaliste and Falkland plateaus). (1977). Documentation of additional biostrati­ The zonation derived from these sites is based al­ graphical events must await recovery of better sec­ most solely on high-latitude taxa, with cosmopoli­ tions. tan species useful only in the lower part ofthe Upper Campanian. The significance of this pattern of pro­ Turonian to Lower Campanian: Turonian to vincialism is discussed below. Lower Campanian sediments have been recovered from the Naturaliste Plateau (Site 258), Falkland Plateau (sites 327 and 511), Northeast Georgia Rise PALAEOCLIMATIC IMPLICATIONS (Site 700), and Kerguelen Plateau (sites 747, 748, and 750). In general, this time interval is represented Although the Cenomanian is too poorly represented by disconformity-bound sequences of pelagic and to yield much information, the Turonian to Maas­ hemipelagic sediments. The spotty nature of core trichtian record that has been recovered is sufficient recovery from some of the sites makes it difficult to to allow examination ofthe palaeoclimatic trends in delineate regional disconformities with a high de­ the Southern Ocean during this interval. The palaeo­ gree of accuracy. It appears, however, that discon- climatic signal contained within these assemblages Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 373

Stage Zone/Subzone c: P stoveri ro ...... C. daniae .c () N. corystus .;:: ...... B. notacu/um Ulro ro G. bicrescenticus ~ N. watkinsii P firthii c: R. parvidentatum ro c: A. p. expansus ro a. R. levis E B. dentata ro 0 G. diabolum G. costatum H. trabeculatus Sant. L. septenarius T. ecclesiastica Can. z. kerguelenensis B. dissimilis K. magnificus Tur. Q. gartnerii

Cena. E. turrisseiffelii I 0 60 maximized species richness II high-latitude species • cosmopolitan species

Fig. 7. Stratigraphic distlibution or maximized species richness by lone/subzone for Upper Cretaceous calcareous nannofossil assemblages of the Southern Ocean. is somewhat obscured by two sources ofnoise in the quence. The other source of noise is monographic. data: preservational and monographic. Preservation No one worker has examined all of the sections in of the nannofossil assemblages often varies signifi­ detail. Nevertheless, these sites have been chosen cantly within and between sequences recovered for the general high quality of the data and it is our from the eleven sites used in this compilation. For belief that these monographic effects are minimal. example, the Lower Maastrichtian is complete at The compilation of the data used to construct the sites 690, 700, and 748. However, poor preservation new zonation for the Turonian to Maastrichtian throughout much of the section at Site 700 signifi­ reveals three general trends. Firstly, the Turonian to cantly degrades the quality ofinformation from this Lower Campanian is characterized by somewhat site. Preservation of nannofossil assemblages from discontinuous sequences of sediments containing Site 748 is often excellent, but is interrupted by nannofossil assemblages that exhibit only limited poorly preserved intervals. At Site 690, on the other endemism. Secondly, a majordisconformity divides hand, good preservation characterizes the entire se- the Lower and Upper Campanian on all of these Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

374 Upper Cretaceous calcareous nannofossils of the Southern Ocean

Stage Zone/Subzone c as P stoveri C. daniae ~ -<.> N. corystus 'C en B. notaculum -as as G. bicrescenticus ::::E N. watkinsii P firthii c R. parvidentatum as c A. p. expansus as R. levis 0- E B. dentata as () G. diabolum G. costatum H. trabeculatus Sant. L. septenarius T. ecclesiastica Con. Z. kerguelenensis B. dissimilis K. magnificus Tur. Q. gartnerii

Cena. E. turrisseiffelii

0 10 20 30

Percent high-latitude species

Fig. x. Plot of the percentage of high-latitude species F('rsus cosmopolitan species by zone/suhzone for Upper Cretaceous calcareolls nannofossils or the SOllthern Ocean. oceanic plateaux. Thirdly, the more complete se­ results of this compilation are given in Table 3. This quences of Upper Campanian to Maastrichtian sedi­ approach tends to minimize the variations in preser­ ments contain nannofossil assemblages that exhibit vation between and within the different sections. In a high degree of endemism. general, the Upper Campanian to Maastrichtian is In order to examine the changes in the nature of represented by subzones from the Falkland Plateau, the nannofossil assemblages through the Upper Cre­ Kerguelen Plateau, and Maud Rise. The Turonian to taceous, we have analyzed the composition and Lower Campanian is represented by subzones from maximized species richness of the assemblages the Naturaliste and Kerguelen plateaux. The number from the sites. The maximized species richness for of high-latitude and cosmopolitan taxa from each each subzone was calculated by counting the total site was also noted and used in the analysis. Table 4 number of species found within that subzone from contains a list of those species considered to be each site and using the maximum number as a data high-latitude taxa. The results of this analysis are point. Only heterococcoliths were considered in this illustrated in Fig. 7. treatment. as the distribution of holococcoliths is As is evident from this figure, the maximized strongly dependent on preservational factors. The species richness ofthe Southern Ocean assemblages Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 375

varies significantly between subzones. The wide the southern cool water province during this time variation of the other subzones is a function of may have triggered increased speciation amongst changes in preservation as well as both high-latitude the high-latitude taxa. and cosmopolitan richness. The lowest richness is The most striking feature of the species richness for the Broinsonia dentata subzone of Mid-Cam­ distribution for the Upper Cretaceous is the substan­ panian age. This value is probably not repre­ tial rise in the number and proportion of high-lati­ sentative, as it is based on only one locality (Site tude taxa that characterizes the Upper Campanian 5 I I), where the subzone is represented by samples and Lower Maastrichtian (Figs 7 and 8). This inter­ that are generally poorly preserved. This subzone val is characterized by a relatively large number of coincides with the widespread disconformity dis­ high-latitude species (average 8.2 per biostrati­ cussed later in this paper. It is clear that the mid­ graphical unit) and a relatively low number of cos­ Campanian disconformity divides the Upper mopolitan taxa (average 29.0 per biostratigraphical Cretaceous into two distinct sets ofsubzones/zones: unit) as compared to the Turonian to Lower Cam­ the Turonian to Lower Campanian and the Upper panian. The peak of this trend occurs in the G. Campanian to Maastrichtian. bicrescenticus Subzone (early Maastrichtian), The Turonian to Lower Campanian is charac­ where the 12 high-latitude taxa account for more terized by a relatively high number ofcosmopolitan than 30% of the total species present. taxa (average 38.2 per biostratigraphical unit) and a This greater contribution by high-latitude taxa relatively low number ofhigh-latitude taxa (average can be traced directly to an increased rate of specia­ 4.3 per biostratigraphical unit). A somewhat ele­ tion that is restricted to three calcareous nannofossil vated level of high-latitude species is present in the families: the Ahmuellerellaceae, Biscutaceae, and Upper Coniacian and Lower Santonian. This pulse Podorhabdaceae. These families gave rise to at least of higher endemism is more clearly delineated in eleven species during the late Campanian through Fig. 8, which indicates the percentage of high-lati­ Maastrichtian. Most striking was the radiation tude species relative to the total number of taxa for within the Podorhabdaceae during this time. At least each subzone. It is clear from this plot that the Z. four taxa including Cribrosphaerella daniae, Psvk­ kerguelenensis Subzone and, to a lesser degree, the tosphaerafirthii. Nephro/ithus corystus, and N. fre­ T ecclesiastica Subzone have a proportion of high­ quens evolved during the late Campanian to early latitude taxa well above the background level of Maastrichtian. These taxa probably were derived approximately 8-11 % per unit. This trend is re­ from Cribrosphaerella ehrenhergii, a species noted flected also in the abundance of Repagulum parvi­ for its preference for high southern latitudes (Wise, den/atum, a well-documented, bipolar, high-latitude 1988; Pospichal & Wise, 1990; Watkins, 1992). An species. Repagulum parvidentatum is a rare, spo­ additional podorhabdoid, Teichorhabdus ethl1los, radic component of the Turonian to Lower appeared in the late Campanian, although its ances­ Coniacian assemblages from the Naturaliste (Table try is uncertain. Within the Ahmuellerellaceae, the I) and Falkland plateaux, and is apparently absent Monomarginatus-Misceomarfiinatus complex gave from the Upper Turonian of the Kerguelen Plateau. rise to at least four taxa. Neocrepidolithus watkinsii It becomes an abundant species during the Upper (= Monomarginatus primus Crux, 1991), which ap­ Coniacian and Lower Santonian at the Naturaliste peared in the late Campanian, appears to have been and Falkland Plateau sites, and is a frequent compo­ the root species for this lineage. At least two new nent of coeval Kerguelen sites. The high-latitude species of Biscutaceae, Biscutum magnum and B. species Seribiscutum primitivul1l mimics the distri­ bole/um, appear in the Upper Campanian and lowest bution of R. parl'identatul1l in the Naturaliste, Falk­ Maastrichtian. Thesejoined B. dissimi/is, B. notacu­ land, and Kerguelen sections. These data suggest lum, and B. coronum (which appeared in the that cooling of the surface waters overlying the Turonian, early Santonian, and early Campanian, Southern Ocean plateaux occurred during the late respectively) to comprise more than 10% of all Coniacian and early Santonian. The expansion of species in the early Maastrichtian Southern Ocean. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

376 Upper Cretaceous calcareous nannofossils of the Southern Ocean

747 264 689 N 752 700 327511 748 S Austral 750 690 Stage Temperate zonation zonation P. stoveri CC26 c: as ...... c. daniae ..c: u CC25 ...... ~ N. corystus en as B. notacufum as ~ G. bicresent. CC24 N. watkinsii P. firthii a. CC23 E R. parvident. as 0 CC22 Consistent A. p. expan.

Fig. 9. Distrihution of Wal:,nmJ(:ria harnesae in the Upper Campanian and Maastrichtian of the Southern Ocean. Latitudinal placement of the sites based on plate reconstmctions of Lawver el at. (1993). Line tyvc indicates the ahundance of W. harnesa(! as follm.\'s: solid line::::: consistent occurrence; dashed line::::: sporadic occurrence; dOlled line::::: absent; no line::::: interval not n:covcrcd at site. Modified from Huber & Watkins (1992).

This interval ofhigh-latitude speciation is accom­ barnesae was present throughout the Maastrichtian, panied by other marked changes in the nannofossil although its occurrence was sporadic during parts of assemblages. Watznaueria barnesae is a nearly u­ the late early Maastrichtian and late Maastrichtian. biquitous nannofossil in Upper Cretaceous assem­ This pattern of exclusion corresponds to the pe­ blages throughout the world. However, this species riod ofgreatest species richness ofhigh-latitude taxa is generally rare or absent from high latitude Maas­ (Fig. 7) and greatest dominance by high-latitude trichtian assemblages (Watkins, 1992; Huber & taxa (Fig. 8). This correspondence suggests that Watkins, 1992). Data from sections on all four significant cooling of the Southern Ocean surface oceanic plateaux, as well as from Site 752 (Broken water commenced by at least the later part ofthe late Ridge), indicates a systematic pattern to the occur­ Campanian and was most pronounced during the rence of W. barnesae in the Southern Ocean during late early Maastrichtian and mid-late Maastrichtian. the late Campanian and Maastrichtian (Fig. 9). The There is evidence of a moderation in climate near species became sporadic and rare earlier at more the early-late Maastrichtian boundary (B. notaeu­ southerly sites (e.g. R. parvidentatum Subzone on fum and N. eorystus Subzones). Watznaueria barne­ Kerguelen and Naturaliste plateaux) and latter at sae once again becomes a common component of more northerly sites (e.g. N. watkinsii Zone on Bro­ Site 752 assemblages, and sporadically reappears at ken Ridge). Watznaueria barnesae was absent for Site 700 (Fig. 9). The maximized species richness most of the late early and latc Maastrichtian at the (Fig. 7) and percentage (Fig. 8) ofhigh-latitude taxa more southern sites, and only reappeared within the declines during this time as net extinction of the latest Maastrichtian (uppermost sample at Site 690; high-latitude species occurs. This period approxi­ uppermost metre of sediment at Site 750). At the mately corresponds with the poleward migration of more northerly Site 700, W. barnesae is absent only at least four species of planktonic foraminifers in­ from two intervals in the mid and Upper Maas­ cluding Globotruneana area, Globotruneana sub­ trichtian. Further to the north (Broken Ridge), W. eireumnodifer, Globotruneanella petaloidea, and Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

Stratigraphy and Biostratigraphy 377

Plate I. Figs. 1-30: Upper Cretaceous species from the Southern Ocean. All figures photographed using crossed polarizcrs except 2..\ lOa. 20. and 28 using phase contrast illumination. Figs 1-7. 17. 2H from Sample 750A-20R-4. I I-I IScm: Figs H-9. I I-I, from Sample 750B-7W-I. O-Icm: Fig. 10 from Sample 511-"-1. 50-5Icm: Figs 14-16.24.27 from Sample 258-10-1. 89-9Ikm: Figs 18-n. 25. 26. 29 from Sample 258-7-1. H9-90cm: Fig. ,0 from Sample 258-1 ,-2. 69-70cm. Scale har in Fig. I is 5 mm. I. Prnlisc()splwcrll s{O\'eri: 2. Nephrolitlllls.!i"fquel1.\' mil1iporus: 3. Nel'''rolithus.li·eqltell.\ji·l~qltel1.\·: 4. Cribro.'iphaerellll dalliae: 5. Nephro/ithlls corY.'ilw': 6. P.\ykw.'ipllllera .firthi'-: 7. Ncocrepidolilhu'\" u'mkillsii; 8. l3i.KwUln IIUlJ.:llum: 9. Reinhart/r;",'s lel'i,\': 10. Gephyrohi.\"CllIfl/l1 dia!Jo/um: II. Vekshillellll lU/c!lella: 12. lJi.\'ctIfUI// corOllUI1I: 13. AS/Jido/illllls /wrcIIs parcu.\"; 14-15. Zel/grlwhdOlllS kergue/ellt!nsis 14. distal view. 15. oblique lateral vit;:w: 16. Quat/nil/I garillerii: 17. G/all/..:o/irhlls bicrescellriclIs: 18. EUlel!irhlfs exil/lius: 19. Kalllprllefills lI/agIlU1cus: 20. Marlhasrerire,\"./il1"Cll1l1s: 21. Broinsonia del/raw: 22. Micu/a decu.\·.wra: 23. Lir/llIsrriJllIs sel'rellarills: 24. ThiersreilJia ecc/esil/srica; 25. EUfe/lir/lIIs llIrriseUle/ii; 26. Tr(//w!irhlls ph(/("(:,/o.ws: 27. /(el'agu/ulII parl'ideflrar1l1ll: 28. Bisel/rlllll cli.\".\'imi/is: 29. Serihiscllll/1//l'ril/lili\'um: 30. EpnJ/ir/IU.\'.IhJfa/is. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

378 Upper Cretaceous calcareous nannofossils of the Southern Ocean

Glohigerinelloides suhearinatus (Huber & Wat­ Ocean Upper Cretaceous utilizes a combination of kins, 1992). The keeled forms (G. area and G. cosmopolitan and high-latitude origination and ex­ suheircumnodifer) apparently invaded the Austral tinction events, with the Cenomanian-Lower Cam­ Realm for an period approximately coincident with panian dominated by cosmopolitan low latitude the mid-Maastrichtian expansion of the geographic species and the late Campanian and Maastrichtian range of W. barnesae. The non-keeled forms (G. dominated by high-latitude species. This dichotomy suhearinatus and G. petaloidea) invaded at about is marked by a prominent disconformity expressed the same time as the keeled forms but persisted in on all four oceanic plateaus thus far drilled. Follow­ the Austral Realm until the end ofthe Maastrichtian ing this hiatus, rapid speciation within at least three (Huber & Watkins, 1992). This mid-Maastrichtian families of calcareous nannofossils led to the estab­ climatic amelioration apparently put an end to the lishment of a distinct austral nannotlora during the pattern ofrapid speciation ofthe austral nannotlora. late Campanian and early Maastrichtian. Cooler sur­ The keeled planktonic foraminifers and W. har­ face-waters and increased vertical mixing of the nesae again disappeared from the austral oceans water column were probably responsible for the during the late Maastrichtian, suggesting a return to ecological separation ofthis Austral Realm from the the earlier, cooler oceanographic conditions. How­ warmer waters to the north. Slight warming in the ever, no new taxa of calcareous nannofossil arose mid-Maastrichtian coincided apparently with the during this late Maastrichtian interval. Indeed, the end of rapid speciation in austral nannofossils. The decline ofthe Austral nannotlora continued with the austral nannotlora steadily declined through the late extinction of P.firthii and M. pectinatus (Fig. 4). In Maastrichtian before its ultimate demise at the Cre­ addition, Nephrolithus frequens migrated towards taceous-Tertiary boundary. the equator (Fig. 6) during this time. Thus, it appears that although the late Maastrichtian may have been ACKNOWLEDGMENTS cooler than the mid-Maastrichtian, the late Maas­ trichtian Southern Ocean was not separated ecologi­ The authors wish to thank the organizers ofthe aDP cally from the low latitude oceans to the degree and the Marine Biosphere conference, who did a necessary for endemic speciation to re-occur. splendid job in all respects. Reviews by Hisatake There is some evidence that the generally cool Okada, Paul Bown, Robin Whatley, and Alicia late Maastrichtian ended with a brief warming pulse Moguilevsky significantly improved the manu­ near the Cretaceous-Tertiary boundary. Wat­ script. znaueria harnesae exhibited a marked poleward migration (Fig. 9) at the top of the Maastrichtian. REFERENCES Huber & Watkins (1992) documented that the planktonic foraminifer Pseudotextularia elegans Basov, I. A.. Ciesielski. P. F., Krashcninnikov, V. A.. Weaver. showed a similar poleward migration at the very end F. M., & Wise. S. W., 11'. 19R3. Biostratigraphic and paleon­ of the Maastrichtian. This was coincident with a tologic synthesis: Deep Sca Drilling Project Lcg 71. Falk­ land Plateau and Argcntine Basin. /11/1. Repls. DSDP, warming recorded in oxygen isotope sequence from Washington (U.S. Govt. Printing Officc), 71, 445-460. Site 690 (Stott & Kennett, 1990; Huber & Watkins, Bukry, D. 1974. Cretaceous and Paleogene coccolith stratigra­ 1992). phy, Deep Sea Drilling Project, Leg 26./l1il. Repls. DSDP. Washington (U.S. Govt. Printing Office), 26, 669-673. Bukry. D. 1975. Coccolith and silicoflagellate stratigraphy near CONCLUSIONS Antarctica. Deep Sea Drilling Project, Leg 2R. /11/t. Rep/s. DSDP. Washington (U.S. Govt. Printing Office). 28, 709­ The stratigraphic sections recovered by the DSDP 723. and ODP cruises to the Southern Ocean have pro­ Cepek, P. & Hay, W. W. 1969. Calcareous nannoplankton and biostratigraphic suhdivision of the Upper Cretaccous. vided a wealth of material for the study of Upper Tral1s. Gulleo"s/ Assoc. Ceol. Soc.. 19.323-336. Cretaceous calcareous nannofossil assemblages. Crux, 1. A. 1991. Caleareous nannofossils recovered by Lcg I 14 The biostratigraphical division of the Southern in the Suhantarctic South Atlantic Ocean. Proc. ODP, Sci. Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

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Results, College Station, TX (Ocean Drilling Program), Watkins, D. K., Wise, S. W., Jr., and Pospichal, J. J., 1989. 114, 155-178, Turonian-Maastrichtian nannofossil biostratigraphy and Davies, T.A., Luyendyk, B,P., et of. 1974, Init. Repts. DSDP, paleoceanography ofthe Southern Ocean. lilt. Nannop!ank­ Washington (U.S, Govt. Printing Office), 26, II29pp. ton Assoc. Newsl., 11, 106. Erba, E" Premoli Silva, I., and Watkins, D,K., 1995. Cretaceous Wind, FH. I979a. Late Campanian and Maestrichtian calcare­ calcareous plankton biostratigraphy of Sites 872 to 879 , ous nannoplankton biogeography and high-latitude biostra­ 157-169. Proc. ODP Scientific Results, 144,157-169. tigraphy (Ph.D. dissert.). Florida State Univ" Tallahassee. Huber, B.T" & Watkins. D.K. 1992. Biogeography of Cam­ Wind, FH. I979b. Maestrichtian-Campanian nannoflora prov­ panian-Maastrichtian calcareous plankton in the region of inces of the southern Atlantic and Indian oceans. In: Tal­ the Southern Ocean: palcogeographic and paleoclimatic wani, M" Hay, W. W. and Ryan, W.B.F. (Eds), Deep Sea implications, Amer. Geophysical Union. Antarctic Re­ Drilling Results in the Atlantic Ocean: Continental Mar­ search Series, 56, 31-60. gins and Paleoenvironment. Am Geophys. Union, Maurice Lawver. L.A., Gahagan, L.M., and Coffin, M.F 1992. The Ewing Ser., 3, 123-137. development of paleoseaways around Antarctica. Amer. Wind, F. H., and Wise, S. W., Jr. 1983. Correlation of upper Geophysical Union. Antarctic Research Series, 56, 7-30. Campanian-lower Maestrichtian calcareous nannofossil as­ Mohr, B.A.R., & Gee, C.T. 1992. Late Cretaceous palynofloras semblages in drill and piston cores from the Falkland Pla­ (sporomorphs and dinocysts) from the Kerguelen Plateau, teau, southwest Atlantic Ocean. Init. Repts. DSDP. Southern Indian Ocean (Sites 748 and 750). Proc. ODP Washington (U.S. Govt. Printing Office), 71, 551-563. Scientific Results, College Station TX (Ocean Drilling Pro­ Wise, S. W.,.Ir. 1983. Mesozoic and Cenozoic calcareous nanno­ gram) 120,281-306. fossils recovered by Deep Sea Drilling Project Leg 71 in the Falkland Plateau region, southwest Atlantic Ocean. Init. Perch-Nielsen, K. 1979. Calcareous nannofossils from the Cre­ Repts. DSDP, Washington (U.S. Govt. Printing Office), 71. taceous between the North Sea and the Mediterranean. In 481-550. Wiedmann, J. (Ed.), Aspekte der Kreide Europa.I·: Int. Un­ ion Geol. Sci. Ser. A. 223-272. Wise, S. W" Jr. 1988. Mesozoic-Cenozoic history of calcareous nannofossils in the region of the Southern Ocean. Palaeo­ Perch-Nielsen, K. 1985. Mesozoic calcareous nannofossils. In geog.. Pa!aeoclimatol.. Pa!aeoecol.. 67,157-179. Bolli. H. M., Saunders, J. B., and Perch-Nielsen, K. (Eds), Wise, S.W.. Jr., and Wind, FH. 1977. Mesozoic and Cenozoic Plankton Stratigraphy: Cambridge (Cambridge University calcareolls nannofossils recovered by DSDP Leg 36 drilling Press), 329-426. in the Falkland Plateau, Southwest Atlantic sector of the Pospichal. U. 1989. Southern high latitude K/T boundary cal­ Southern Ocean. Init. Repts. DSDP, Washington (U.S. careous nannofossils from ODP Sites 690 and 752. lilt. Gov!. Printing Office), 36, 269-294. Nallnoplankton Assoc. Nnvsl" 11,90-91. Pospichal, J. J., & Wise, S. W" Jr. 1990. Maestrichtian calcareous nannofossil biostratigraphy of Maud Rise ODP Leg I 13 TABLE 3 - Taxa considered to be high-latitude Sites 689 and 690, Weddell Sea. Proc. ODP. Sci. Results. species in this study College Station TX (Ocean Drilling Program), 113, 465­ Aeuturris seofUs 487. Biseutum bo/etum Schlich, R., Wise, S. W" Jr. et 01" 1989. Pmc. ODP. Init. Repts., College Station, TX (Ocean Drilling Program). 120, 648pp. Biseutum eoronulll Sissingh, W. 1977. Biostratigraphy of Cretaceous calcareous Biseutum dissimilis nannoplankton. Geol. Mijnhomv, 56, 37-50. Biseutum hattnerii Sliter, W. Y., 1977. Cretaceous foraminifera from the southwest Biseutum magnum Atlantic Ocean, Leg 36, Deep Sea Drilling Project. Init. Repts. DSDP. Washington (U.S. Gov. Printing Office), 36, Biseutum notautlum 519-573. Centosphaera barbata Stott, L.D" and Kennett. J.P. 1990. The paleoceanographic and Cribrosphaerella daniae paleoclimatic signature of the Cretaceous/Paleogene boundary in the Antarctic: Stable isotope results from ODP Gephyrobiseutum diabolum Leg 113. Pmc. ODP Sci. Results, Washington (U.S. Gov!. Miseeomarginatus p/eniporLts Printing Office). 113,829-848. Monomarginatus peetinatus Thierstcin, H.R. 1974. Calcareous nannoplankton - Leg 26, Deep Sea Drilling Project. Init. Rept.l. DSDP, Washington (U.S. Monomarginatus quaternarius Govt. Printing Office), 26, 619-667. Neoerepido/ithus watkinsii Watkins, D. K" 1992. Upper Cretaceous nannofossils from Leg Nephrolithus eorystus 120, Kerguelen Plateau, Southern Ocean. Proc. ODP, Sci. Nephro/ithusfrequens Results, College Station TX (Ocean Drilling Program), 120, 343-370. Oetoeyelus reinhardtii Watkins, D.K" Quilty, P.G" Mohr, B.A.R., Mao. S" Francis. Psyktosphaeret jirthii J.E., Gee. C.T.. and Coffin, M.F. 1992. Cretaceous Paleon­ Repagu/um parvidentatum tology of the central Kerguelen Plateau. Proc. ODP. Scien­ titic Rcsults, College Station TX (Ocean Drilling Program), Seribiseutum primitivum 12(),951-960. Teiehorhabdus ethmos Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

380 Upper Cretaceous calcareous nannofossils of the Southern Ocean

Thiersteinia ecclesiastica Cribrosphaerella daniae Perch-Nielsen (1973) Vekshinella aachena Cribrosphaerella ehrenbergii (Arkhangelsky) De­ Zeugrhabdotus kerguelenensis flandre in Piveteau (1952) Cyclagelosphaera margerelii Noel (1965) Cylindralithus crassus Stover (1966) Appendix - Calcareous nannofossils cited in this Eiffellithus eximius (Stover) Perch-Nielsen (1968) report. Eiffellithus gorkae Reinhardt (1965) Eiffellithus turriseiffelii (Deflandre) Reinhardt Acuturris scotus (Risatti) Wind & Wise in Wise & (1965) Wind,1977 Ellipsagelmphaera ovata (Bukry) Black (1973) Ahmuellerella octoradiata (Gorka) Reinhardt Epralithusfloralis (Stradner) Stover (1966) (1964) Gartnerago costatum (Gartner) Bukry (1969) Arkhangelskiella cymbiformis Vekshina (1959) Gartnerago obliquum (Stradner) Noel (1970) Arkhangelskiella specillata Vekshina (1959) Gephyrobiscutum diabolum Wise (1988) Aspidolithus parcus constrictus (Hattner et al.) Gephyrorhabdus camarata (Bukry) Wise (1983) Perch-Nielsen (1984) Gephyrorhabdus coronadventis (Reinhardt) Hill Aspidolithus parcus expansus (Wise & Watkins) (1976) Perch-Nielsen (1984) Glaukolithus bicrescenticus (Stover, 1966) Aspidolithus parcus parcus (Stradner) Noel (1969) Haqius circumradiatus (Stover) Roth (1978) Axopodorhabdus albianus (Black) Wind & Wise in Helicolithus traheculatus (Gorka) Verbeek (1977) Wise & Wind, 1977 Kamptnerius magnificus Deflandre (1959) Biantholithus sparsus Bramlette & Martini (1964) Lapideacassis tricornus Wind & Wise in Wise & Biscutum constans (Gorka) Black in Black & Bar­ Wind (1977) nes (1959) Lithastrinus grillii Stradner (1962) Biscutum coranum Wind & Wise in Wise & Wind Lithastrinus moratus Stover (1966) (1977) Lithastrinus septenarius Forchheimer (1972) Biscutum dissimilis Wind & Wise in Wise & Wind Lithraphidites acutus Verbeek & Manivit In (1977) Manivit et al. (1977) Biscutum hattnerii Wise (1983) Lithraphidites carniolensis Deflandre (1963) Biscutum magnum Wind & Wise in Wise & Wind Lucianorhahdus cayeuxii Deflandre (1959) (1977) Lucianorhabdus maleformis Reinhardt (1966) Biscutum notaculum Wind & Wise in Wise & Wind Manivitella pemmatoidea (Deflandre) Thierstein ( 1977) (1971 ) Braarudosphaera bigelowii (Gran & Braarud) De­ Marthasterites furcatus (Deflandre) Deflandre flandre (1947) (1959) Broinsonia dentata Bukry (1969) Microrhabdulus belgicus Hay & Towe (1963) Broinsonia furtiva Bukry (1969) Micrarhahdulus decoratus Deflandre (1959) Calculites obscurus (Deflandre) Prins & Sissingh in Microstaurus chiastius (Worsley) Griin in Griin & Sissingh (1977) Allemann (1975) Chiastozygus bifarius Bukry (1969) Micula concava (Stradner) Verbeek (1976) Chiastozygus garrisonii Bukry (1969) Micula decussata Vekshina (1959) Chiastozygus litterarius (Gorka) Manivit (1971) Misceomarginatus pleniporus Wind & Wise In Chiastozygus propagulis Bukry (1969) Wise & Wind (1977) Corollithion exiguum Stradner (1961) Monomarginatus pectinatus Wind & Wise in Wise Cretarhabdus conicus Bramlette & Martini (1964) & Wind (1977) Cretarhabdus surrirellus (Deflandre) Reinhardt Monomarginatus quaternarius Wind & Wise in (1970) Wise & Wind (1977) Watkins, Wise, Pospichal & Crux in Microfossils and Ocean Environments, Moguilevsky & Whatley, eds. Proceedings of the "ODP and the Marine Biosphere" International Conference (Aberystwyth, Wales, April 19-21, 1994) Copyright 1996, University of Wales. Used by permission.

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Neocrepidolithus watkinsii Pospichal & Wise Seribiscutum primitivum (Thierstein) Filewicz et al. (1990) in Wise & Wind (1977) Nephrolithus corystus Wind (1983) Stoverius achylosus (Stover) Perch-Nielsen (1984) Nephrolithus frequens frequens Gorka (1957) Stoverius biarcus (Bukry) Perch-Nielsen (1984) Nephrolithus frequens miniporus (Reinhardt & Stoverius coronatus (Bukry) Perch-Nielsen (1984) Gorka) Pospichal & Wise (1990) Stradneria crenulata (Bramlette & Martini) Noel Octoeyclus reinhardtii (Bukry) Wind & Wise in (1970) Wise & Wind (1977) Tegumentum stradneri Thierstein in Roth & Thier­ Petrarhabdus copulatus (Deflandre) Wind & Wise stein (1972) in Wise (183) Teichorhabdus ethmos Wind & Wise in Wise & Placozygus fibuliformis (Reinhardt) Hoffmann Wind (1977) (1970) Tetrapodorhabdus decorus (Deflandre) Wind & Plaeozygus sigmoides (Bramlette & Sullivan) Wise in Wise & Wind (1977) Romein (1979) Thiersteinia ecclesiastica Wise & Watkins in Wise Prediseoclphaer(l avitus (Black) Perch-Nielsen (1983) (1984) Tranolithus exiguus Stover (1966) Prediscosphaera eolumnata (Stover) Perch-Niel­ Tranolithus minimus (Bukry) Perch-Nielsen (1984) sen (1984) Tranolithus phacelosus Stover (1966) Prediscosphaera cretacea (Arkhangelsky) Gartner Vekshinel/a aachena (Bukry) Shafik & Stradner (1968) (1971 ) Prediseosphaera intereisa (Deflandre) Shumenko Vekshinel/a anfiusta (Stover) Verbeek (1977) (1976) Vekshinella dibrachiata Gartner (1968) Prediscosphaera ponticula (Bukry) Perch-Nielsen Vekshinel/a parma Wind & Wise in Wise & Wind (1984) (1977) Prediscosphaera spinosa (Bramlette & Martini) Vekshinel/a stradneri Rood et al. (1971) Gartner (1968) Watznaueria bamesae (Black) Perch-Nielsen Prediscosphaera stoveri (Perch-Nielsen) Shafik & (1968) Stradner ( 1971) Watznaueria supracretacea (Reinhardt) Wind & Quadrum gartneri Prins & Perch-Nielsen in Wise in Wise & Wind (1977) Manivit et al. (1977) Zeugrhabdotus elegans Gartner (1968) Quadrum gothicum (Deflandre) Prins & Perch­ Zeugrhabdotus erectus (Deflandre) Reinhardt Nielsen in Manivit et al. (1977) (1965) Quadrum tr~fidum (Stradner) Prins & Perch-Nielsen Zeur;rhabdotus kerguelenensis Watkins (1992) in Manivit et al. (1977) Zeugrhabdotus pseudanthophorus (Bramlette & Reinhardtites anthophorus (Deflandre) Perch-Niel­ Martini) Perch-Nielsen (1984) sen (1968) Zeur;rhabdotus xenotus (Stover) Hill (1976) Reinhardtites levis Prins & Sissingh in Sissingh (1977) Repagalum parvidentatum (Deflandre) Forchhe­ imer (1972) Rhafiodiscus anfiustus (Stradner) Reinhardt (1971) Rhagodiscus splendens (Deflandre) Verbeek (1977) Rotelapil/us crenulatus (Stover) Perch-Nielsen (1984) Rotelapil/us lafittei (Noel) Noel, 1973 Scampanella comuta Forchheimer & Stradner (1973)