No abstract

We interpret ~40 000 km of multichannel seismic reflection lines collected by the Russian Antarctic Expedition along the East Antarctic continental margin between 32 o E and 115 o E, and present a revised seismic stratigraphic model for depositional paleoenvironments of the region. Variations in acoustic facies characteristics observed across major seismic horizons are correlated with paleoenvironmental changes deciphered from Antarctic drilling data and deep-sea "proxy" records. Our results, as well as other studies, indicate that the East Antarctic margin was glaciated at different times. Glacial ice first reached the western Wilkes Land margin in the Middle Eocene and then advanced onto most parts of the East Antarctic continental shelf during the earliest Oligocene. During the Neogene, bottom currents deposited a variety of drift deposits along the margin.

No abstract

This study is based on about 4000 km of MCS, magnetic and gravity data as well as 10 sonobuoys collected by the 2005 Russian Antarctic Expedition in the Mawson Sea and adjacent Australian-Antarctic basin between 102°E and 115°E. Major identified tectonic provinces and features of the study region include: 1) A marginal rift about 300 km wide which developed as a result of extreme crustal extension and unroofing of the upper mantle, and 2) An oceanic basin with the crust of not older than 81 Ma, which is characterized by ultraslow sea-floor spreading rates ranging from 3 to 11 mm/yr. Three major unconformities are identified in the sedimentary cover of the Mawson Sea and are interpreted to be caused by break-up between Australia and Antarctica at about 81 Ma ago (WL1), the first arrival of the ice sheet to the Mawson Sea (WL3) and continental scale glaciation at about 34 Ma ago (WL4).

No abstract