ANTARCTIC CLIMATIC AND TECTONIC HISTORY BY STRATIGRAPHIC DRILLING: ANDRILL

ANDRILL, a new initiative led by 5 nations (Germany, Italy, NZ, UK and US), plans to use fast-ice and ice shelves as a drilling platform to obtain high-resolution (0.1 to 100k.y.), seismically-linked and chronologically well-constrained stratigraphic records from key locations on the Antarctic continental margin. Key scientific objectives and questions will be addressed in a series of discrete portfolios, the first being McMurdo Sound, which is located on the margin of the Victoria Land Basin, and is influenced by ice and sediment input from both the East and West Antarctic ice sheets. It has the best-understood marginal sedimentary record in Antarctica from 30 years of integrated seismic and drill-core data, which provide confidence in target location. By being located on the rift margin of the Transantarctic Mountains within a major Cenozoic volcanic province, the role of tectonics in climatic and ice sheet development also can be assessed in an excellent chronological framework through input of tephra.

Major aims of the McMurdo Sound Portfolio are: 1) to determine the fundamental behavior of the Antarctic cryospheric system (ice sheet, ice shelf, and sea-ice), including the magnitude and frequency of its changes on 10² - 10⁶ year time-scales; 2) to obtain geological records from critical intervals in the development of the Antarctic cryosphere to guide and constrain glacial and climate models; 3) to document the evolution and timing of major Antarctic rift and tectonic systems and the stratigraphic development of associated sedimentary basins; and 4) to determine, through correlation of near-ice margin and Southern Ocean stratigraphic records, the role of Antarctic ice sheets on long- and short-order Cenozoic climate change, particularly in modulating thermohaline ocean circulation, changing sea-level elevation, and in atmospheric interactions that may transfer or receive global climate change signals. Current target areas are in New Harbor (Eocene-Pliocene targets; mid-late Miocene focus), Mackay Sea Valley (Holocene-Pleistocene and older Neogene targets), McMurdo Ice Shelf (Plio-Pleistocene targets) and Southern McMurdo Ice Shelf (Paleogene targets). An ANDRILL International Workshop report and a Science and Logistical Implementation Plan are available soon at http://andrill-server.unl.edu/.