Pliocene-Pleistocene Glaciomarine Sedimentation in Eastern Prydz Bay and Development of the Prydz Trough-Mouth Fan, ODP Sites 1166 and 1167, East Antarctica

Lithostratigraphy, grain sizes and down-hole logs of Site 1166 on the continental shelf, and Site 1167 on the upper slope, are analyzed to reconstruct glacial processes in eastern Prydz Bay and the development of the Prydz trough-mouth fan. In eastern Prydz Bay upper Pliocene-lower Pleistocene glaciomarine sediments occur interbedded with open-marine muds and grade upward into waterlaid tills and subglacial tills. Lower Pleistocene sediments of the trough-mouth fan consist of coarse-grained debrites interbedded with bottom-current deposits and hemipelagic muds, indicating repeated advances and retreats of the Lambert Glacier-Amery Ice Shelf system with respect to the shelf break. Systematic fluctuations in lithofacies and down-hole logs characterize the upper Pliocene-lower Pleistocene transition at Sites 1166 and 1167 and indicate that an ice stream advanced and retreated within the Prydz Channel until the mid Pleistocene. The record from Site 1167 shows that the grounding line of the Lambert Glacier did not extend to the shelf break after 0.78 Ma. Published ice-rafted debris records in the Southern Ocean show peak abundances in the Pliocene and the early Pleistocene, suggesting a link between the nature of the glacial drainage system as recorded by the trough-mouth fans and increased delivery of ice-rafted debris to the Southern Ocean

Leg 195: seafloor observatories and the history of the Kuroshio Current

Leg 195 had three distinct objectives. The first was to install a long-term geochemical observatory at a cold vent in the throat of South Chamorro Seamount, an active serpentine mud volcano in the Mariana forearc which is bringing fluids, mud, metamorphic rocks and mantle xenoliths to the seafoor from the decollement 25 km below. The second was to install a state-of-the-art borehole seismic observatory almost 600 m below the seafloor in the middle of the Philippine plate to fill an important gap in the International Ocean Network (ION) net. The third was a contingency objective. If time allowed, piston cores were to be obtained at a shallow water site under the Kuroshio Current in order to study climate change in east Asia over the past 1.5 my