The biostratigraphic position of the Kap Kflbenhavn Formation based upon its foraminifera ROLF W. FEYLING-HANSSEN Feyling-Hanssen, R . W. 1987: The biostratigraphic position of the Kap Kebenhavn Formation based upon its foraminifera. Polar Research 5 n . s . , 345-346. Rolf W . Feyling-Hanssen. Department of Micropaleontology, Geological Institute, Aarhur University, D K - 8000 Aarhur C . Denmark. Two lithological units are distinguished in the Kap Kebenhavn Formation (Funder & Hjort 1980; Funder et al. 1984; Funder et al. 1985): a lower member A composed mainly of clay, and an upper member B composed mainly of sand. An upper subunit of the latter. 8 2 , comprises silty deposits. These sediments are in many places deformed and disturbed, partly squeezed and overthrusted. most probably by subsequent overriding glaciers. This blurs the stratigraphic picture at many places. Fossil foraminifera occur in many samples from the fine grained sediments of member A and of unit B2 and also in Fig. 1. Localities mentioned in the text. some samples from thc upper part of unit B1. Some of the foraminiferal assemblages are well preserved, whereas others are in a poorer state of preservation. Many samples were barren of foraminifera even though molluscan shells occurred in them. Dissolution of the delicate calcium carbopate tests by ground water may have taken place. During periods of melting this water probably becomes acidic owing to percolation through the sediments which may be very rich in plant debris. Foraminifera1 assemblages from member A are characterized by the planispiral species Nonion erucopsis Todd (1957). This species is an intermediate form between the Oligocene-Miocene Nonion affine (Reuss) and the Pleistocene Nonion barleeanum (Williamson). Nonion erucopsis often occurs abundantly, thus forming a Nonion erucopsis assemblage zone. It sometimes occurs together with a probably not previously described Elphi- dium with a sharp, almost keeled periphery. Sometimes Car- sidulina laevigata d’Orbigny and Carsidulina teretis Tappan are more frequent than this Elphidium. A few specimens of Cibi- cides grossa Ten Dam & Reinhold may also be present. These assemblages do not reflect a Quaternary arctic environment. but are much closer to Upper Pliocene assemblages from Lodin Elv. East Greenland (Feyling-Hanssen et al. 1982). Clyde Fore- land, and the Qivituq Peninsula, Baffin Island (Feyling-Hanss.cn 1976,1980,1985). They are also very similar to Upper Pliocene assemblages in borings from the central North Sea (King 1983; Feyling-Hanssen 1986). The Nonion erucopsis assemblages from member A of the Kap K0benhavn Formation are thus of Upper Pliocene age. Sediment samples from the upper part of unit B1 and the lower part of unit 8 2 contain well preserved foraminifera1 assemblages. Even though the small species Nonion nioeum Lafrenz dominates these assemblages, the large, conspicuous, planispiral species Elphidiella rolfi Gudina & Palovova char- acterizes them. (This species was referred to as Elphidiella cf. subcarinata in Funder et al. 1985). Elphidiella rolji was described from uppermost Pliocene/lowermost Pleistocene deposits of Ajon Island, northern Chukotka, USSR (Gudina et al. 1984). Elphidiella hannai (Cushman & Grant 1927) is found together with Elphidiella rolfi in the Plio-Pleistocene deposits of the Ajon Island. and a few specimens of this species are also found together with E. rolfi in the Kap Kdbenhavn Formation. Elphi- diella hannai is known from Pliocene/Pleistocene transitional deposits in the Nome area (Cushman 1941), o n the Seward Peninsula (Hopkins et al. 1974), in Beaufort Sea borings (McNeil et al. 1982) and particularly from the southern North Sea basin (La. Doppert 1980). 346 Rolf W . Feyling-Harmen The Elphidiella r o b assemblage zone of the upper unit B1 and lower unit B2 of the Kap Kebenhavn Formation thus marks the transition between the Pliocene and the Pleistocene. Samples from the upper and major part of unit 8 2 usually contain well preserved foraminiferal assemblages with large amounts of Elphidium excauatum (Terquem). This species occurs together with Nonion nioeum, Nonion orbiculare (Brady). Elphidrum rutulaturn Todd and Buccella frigida (Cushman). Scattered specimens of Elphidiella hannai and E . ro@ are also present Assemblages from the lower part of these deposits contain many specimens of the families Polymor- phinidae and Glandulinidae. whereas Cmsidulina reniforrne d’Orbigny, Elphidium bartlelli Cushman and Elphidiwn asklundi Brotzen are more important in the upper part of the subunit. Many specimens of Elphidium excavarurn from the lower part of these deposits have a more or less subacute periphery. whereas they are more broadly rounded in the upper part. Some specimens of the large and characteristic Elphidiella gorbunoui Stschedrina also occur in the upper part of this Elphrdium exravatum assemblage zone of the Kap Kabenhavn Formation. This Elphrdium excavatum zone. particularly its upper part. reflects a high-arctic environment. Comparison with Pleistocene assemblages from many parts of the northern hemisphere (i.a. Cushman 1941; Hopkins et al. 1974; Gudina et al. 1984) shows that i t belongs to the lower part of the Pleistocene. In particular. comparison w i t h foraminiferal assemblages i n North Sea borings (i.a. Asbj0rnsdottir 1987) places the EIphidium excaoatum assemhlage zone of the Kap K ~ b e n h a v n Formation in the lower part of the Early Pleistocene. Thc foraminifera thus reveal that the Kap K ~ h e n h a v n For- mation. or at least parts of i t . wab deposited on an inner shelf. in a sublittoral to littoral environment during the Upper Pliocene to lower Early Pleistocene. Open water must have occurred, at least seaxonally. in thc area during this period. This conclusion is in good agreement with results reached by Funder and co- workers already in 1984. References Asblornsdottir. L. 1Y87: TheJosephine boring (3Oil3-2.r). Cen- tral North Sea. Unpublished thesis. Geol. Inst.. Aarhus Lniversity. 150 pp Cushman. J . A . I Y - l l . Somc fossil foraminifera from Alaska: Ciuhman Lahoratory for Foraminifera1 Research Con- tribution 227. 32-38 Cushman. J . A . 82 Grant. U . S . . I V . 1927: Late Tertiary and Ouaternary Elphidiums of the west coast of North America. Sun Diego Sociec of Natural Hitton. Transactions 5/61, 6% R?. Doppert. J . W . C. 1980: Lithostratigraphy and biostratigraphy of marine neogene deposits in the Netherlands. Mededelingen van de Geologuche Stichting 32-16, 255-311. Feyling-Hanssen, R . W . 1976: The Clyde Foreland Formation, a micropaleontological study of Quaternary stratigraphy. 1st Int. syrnp. on Benthonic Foraminifera of Continental Margins, PI. B: Paleoecology and Biosfraligraphy, Maritime Sediments, Spec. Pub. I . 31S377. Feyling-Hanssen, R. W . 1980: Microbiostratigraphy of young Cenozoic marine deposits of the Qivituq Peninsula, Baffin Island. Marine Micropaleontology 5 , 15?-184. Feyling-Hanssen. R . W . 1985: Late Cenozoic marine deposits of East Baffin Island and East Greenland, microbio- stratigraphy - correlation - age. Pp. 356393 in Andrews. J. T. (ed.): Quaternary Enuironments: Eastern Canadian Arctic, Baffin BRV. and Wesi Greenland. Allen and Unwin. London, Sydney. Feyling-Hanssen. R . W. 1986: Grznsen mellem Tertier og Kvartzr i NordsQen og i Arktis. fastlagt og korreleret ved hjzlp af benthoniske foraminiferer. Dansk geol. Foren., Arsskrift for 1985, 19-33. Feyling-Hanssen. R . W., Funder, S . & Petersen. K. 1982: The Lodin Elv Formation; a Plio-Pleistocene occurrence in Greenland. Bull. Geol. S O C . Denmark 31. 81-106. Funder. S . , Abrahamsen. N.. Bennike, 0. & Feyling-Hanssen, R . W. 1985: A forested Arctic, evidence from North Greenland. Geology. 542-546. Funder. S . , Bennike. 0.. Mogensen. G . S . , Noe-Nygaard, B.. Pedersen, S. A . S . & Petersen, K. S. 1984: The Kap Kebenhavn Formation, a late Cainozoic sedimentary sequence in North Greenland. Rapport Gr@nlands Geo- logirke Undersmgelse 120, 9-18. Funder. S . & Hjort, C. 1980: A reconnaissance of the Quat- ernary geology of eastern North Greenland. Rapport Gr@n- lands Geologiske lJnders@gelse 99, 99-105. Gudina. V . I . , Lashtabeg. V . A . . Levchuk. L. K., Polovova, T . P., Sukhoroslov, V . L. 1984: The Pliocene/Pleistocene boundary in northern Chukotka. based on foraminifera, Transaction of the Institute of Geology and Geophysics 560, Akademia Nauk SSSR. S.O. 104 pp. Hopkins, D . M., Rowland, R . W . . Echols. R . E . & Valentine, P. C. 1974: An Anvilian (Early Pleistocene) marine fauna from western Seward Peninsula, Alaska. Quaternary Research 4(4), 44-470. King. C. & Hughes, M. J . (contributor) 1983: Cainozoic micro- palaeontological biostratigraphy of the North Sea. Institute of Geological Sciences, Report 8217. 40 pp. McNeil. D. H . , Ioannides. N. S . & Dixon. J . 1982: Geology and biostratigraphy of the Dome Gulf et al. Ukalerk C-50 Well, Beaufort Sea. Geological Survey of Canada. Paper 80-32. 1-17. Todd. R . 1957: Foraminifera from Carter Creek, northeastern Alaska. U . S . Geological Survey. Professional Paper 294-F, D L 2 3 5 .