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Cape Roberts 
The Cape Roberts Project (CRP) (1995-2000) was a cooperative venture between scientists and science administrators from seven nations: Australia, Germany, Italy, The Netherlands, New Zealand, the United Kingdom, and the United States of America. The goals of the project were to document paleoenvironmental change, the early history of the East Antarctic ice sheet (EAIS), and the tectonic histories of the Transantarctic Mountains (TAM) and the West Antarctic Rift System (WARS) through the recovery of stratigraphic records off Cape Roberts (77.0 o S, 163.7 o E). A sedimentary succession ~1500m-thick (with 95% core recovery) was obtained in three drill holes, spanning the time period 17 to 34 Ma and 100 m of basement (Davey et al., 2001). Chief results of the Cape Roberts Drilling Program indicate that between 34 and 25 Ma this sector of East Antarctica was characterized by a cool temperate climate with low-diversity woody vegetation. Temperate mountain glaciers, and possibly inland ice sheets, were releasing icebergs to the Ross Sea. The climate between 25 and 17 Ma was sub-polar with periods of more extensive grounded ice and low, sparse tundra on the adjacent mountains. Whereas the TAM had achieved most of their present height by 34 Ma, results indicate that most subsidence in the Victoria Land Basin (VLB) occurred after 34 Ma and coincided with the onset of the present phase of volcanism in the McMurdo Sound region. The difference in elevation of Beacon Supergroup rocks penetrated in cores and their counterparts in adjacent mountains indicates a vertical offset of more than 3000 m in basement rocks across the coastal region. Perhaps the most significant result from CRP was the recognition of cyclicity in sedimentary deposition with Milankovitch frequency (inset A) that could be correlated to three orbital and sub-orbital events across the Oligocene-Miocene boundary known from deep-sea proxy records (Naish et al., 2001). A serendipitous discovery during CRP drilling was the recovery of a lower Pleistocene carbonate interval (inset B) that is interpreted to reflect a prolonged, warm interglacial period under significantly reduced sea-ice and the probable absence of the Ross Ice Shelf (RIS) and West Antarctic Ice Sheet (WAIS) during Marine Isotope Stage 31 (1.07 Ma) (Scherer et al., 2003). The composite ~1500 m-thick stratigraphic section on the Antarctic continental shelf, proximal to the Antarctic cryosphere, serves as the basis for regional and global paleoenvironmental correlations to Antarctic events and as a reference section for Antarctic chronostratigraphy for the time period 17 to 34 Ma. Results of the CRST are published in the series of Initial Report and Scientific Results volumes listed below. Cape Roberts Science Team, 1998a. Initial Report on CRP-1, Cape Roberts Project, Antarctica; Barrett, P.J., Fielding, C.R., Wise, S.W., Jr., (eds.). Terra Antartica, 5 (1), 1-187. For more information about the Cape Roberts project visit http://www.vuw.ac.nz/geo/croberts/ |
