Collaborative Research: Initial Palynological Characterization of Cape Roberts Drill Cores

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Wrenn OPP 9527075 Askin OPP 9527013 Abstract The Cape Roberts Project (CRP) is designed to core submarine deposits in the western Ross Sea that range in age from middle Late Cretaceous-early Miocene. Four, 500m long drillcores will be taken from a platform of annual sea ice floating in water depths ranging from 100 to 500m. The cores will sample a composite stratigraphic section 1500m thick during two, 45-day-long drilling seasons (October-November 1996 and 1997). Shipboard geophysical surveys have identified a package of dipping sedimentary strata interpreted to be Cretaceous-Miocene in age. A thin blanket of younger sediments overlies these beds. Rocks of this age range are not known from the Ross Sea, the Transantarctic Mountains or elsewhere in East Antarctica. Thus, recovered sediments of this age have prime importance for interpreting Antarctic geologic, biologic, climatic and tectonic history during the Cretaceous-Cenozoic. Objectives of CRP include obtaining a late Cretaceous-Cenozoic paleoclimatic record, studying glacial-deglacial and eustasy cycles, and determining the Gondwana breakup and rifting history of the Ross Sea embayment. Core description and downhole experiments will be conducted at each drill site. An international team of biostratigraphers, sedimentologists, magnetostratigraphers, petrologists, etc. will conduct initial characterization of the cores and their constituents during and immediately following drilling at the fully equipped Crary Science and Engineering Center (CSEC), McMurdo Station, Ross Island, Antarctica. Palynomorphs have proven to be invaluable tools for biostratigraphic and paleoenvironmental interpretation of younger Ross Sea sequences drilled in the Ross Sea Embayment. They include both marine (dinocysts) and nonmarine (spores, pollen) types, record extensive and diverse geologic information, and are preserved in a wide variety of lithofacies formed in various paleoenvironments. This award suppor ts initial palynological characterization of the CRP drillcores, in collaboration with New Zealand palynologists. All samples will be processed in the CSEC using a focused mircowave digestion unit for maximum safety and effieciency. Analyses will focus on providing palynological input for an integrated biostratigraphic and paleoenvironmental framework based on all microfossils groups present. This critical framework is of fundamental importance to all future geologic, geophysical and paleontologic studies conducted on the cores and in the drilling area. Palynology will also provide vital data for prime CRP objectives: climate change, eustasy, and thermal and tectonic history. Future palynologic studies of the cores include such topics as paleoenvironments, vegetational and climatic change, taxonomy, evolution of southern marine and terrestrial floras, endemism, dispersal and paleobiogeography, and extinction events.