Reed P. Scherer and Nalân Koç


  Diatom occurrence, abundance, and biostratigraphic position are documented from Paleogene sediments of Ocean Drilling Program (ODP) Leg 151 in the high-latitude Norwegian-Greenland Sea. Previous ocean drilling in the Norwegian-Greenland Sea (ODP Leg 104, Deep Sea Drilling Project [DSDP] Leg 38) provided incomplete Paleogene sections. Paleogene sediments recovered as part of ODP Leg 151 contribute toward a regional composite stratigraphic section, although significant gaps remain. The Paleogene diatom assemblages of Leg 151 differ from those previously recovered, thereby contributing to the development of a regional diatom biostratigraphic zonal scheme. Biosiliceous upper Paleogene sediments were recovered from Hole 908A in the Fram Strait and Hole 913B along the northeast Greenland Margin. Hole 908A contains an upper lower to lower upper Oligocene diatom assemblage dominated by resting spores and other diatoms that suggest high productivity in a neritic setting. The youngest diatom assemblage present in the sequence approximates the oldest Oligocene diatom assemblage of DSDP Leg 38, Site 338, of the Sceptroneis pupa Zone. Conformably beneath the S. pupa Zone in Hole 908A is the upper lower Oligocene Sceptroneis fennerae Zone, which is defined in this study. The Cymatosira praecompacta Zone, defined here, conformably underlies the S. fennerae Zone. Hole 913B contains biosiliceous successions containing a diatom assemblage with an upper upper Eocene character but also including lower lower Oligocene elements. This assemblage defines the Actinoptychus irregularis Zone, established here, which resembles biosiliceous sediments recovered at Site 339 of DSDP Leg 38. The lowermost in situ diatoms recovered include an assemblage of middle Eocene pyritized forms in Hole 913B. Reworked lower Paleogene diatoms occur in upper Paleogene sediments of Sites 908 and 913 and in Pliocene and Quaternary glacially influenced sediments, particularly those of the Yermak Plateau (Sites 910, 911, and 912). Two new species are described, Sceptroneis fennerae n. sp. and Thalassiosira nansenil n. sp. T. nansenii formally names the widely distributed high-latitude diatom previously known as Thalassiosira affn. irregulata. Rhizosolenia oligocaenica var. styliforma n. var. and Sceptroneis humuncia var. rondipoda n. var. are also defined.

Date of initial receipt: 28 July 1995
Date of acceptance: 18 December 1995

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