Biostratigraphic Summary of DSDP Leg 44: Western North Atlantic Ocean

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During Leg 44 of the Deep Sea Drilling Project five sites (388-392) comprising 11 holes were drilled in the western North Atlantic Ocean off the east coast of the United States. Water depth at the sites ranges from about 2600 to 5000 meters. A total of 1342.5 meters was cored of which 546.8 meters were recovered (41%) in 149 cores. Sediments range from Upper Jurassic through Quaternary although no Cenomanian-Santonian, upper Eocene-(?) Oligocene, and Pliocene sediments were found. Most of the cores recovered were studied both for calcareous nannoplankton (R. Schmidt) and foraminifers (F.M. Gradstein). Tertiary sediments were analyzed for radiolarians (F. Weaver). In addition to these investigations by the three shipboard micropaleontologists, biostratigraphic contributions were received on Cenozoic nannofossils, silicoflagellates and diatoms (D. Bukry), Lower Cretaceous pollen and spores (D. Habib), Lower Cretaceous aptychi (O. Renz), Cretaceous nannofossils (P.H. Roth), and Upper Jurassic nannofossils of the Jurassic/Cretaceous boundary (F.H. Wind), and Cretaceous ostracodes (F. Swain). Bukry also reports on nine samples from Site 394 drilled near Site 391 during Leg 44A, an engineering trial to test the readiness of Glomar Challenger for the International Phase of Ocean Drilling (IPOD). In addition, 38 Cretaceous-Cenozoic samples from Site 390 and 392 were processed for palynomorphs (G. Williams), but the results were very disappointing. Diatoms are meager to abundant in the Blake-Bahama Basin Miocene of Cores 3 to 19 from Hole 391A and Cores 5 and 6 from Hole 394A. Diatoms are common in the Blake Nose Eocene of Cores 2 to 7 from Hole 390A. Both sequences are briefly described in conjunction with silicoflagellate studies. The stratigraphic distribution and relative abundance of microfossil groups from the Leg 44 and 44A sites are given schematically in Figure 1.