Crustal structure and evolution of the Mawson Sea, western Wilkes Land margin, East Antarctica

Thisstudy 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-floorspreading ratesranging 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).