Tuesday, 28 August 2007 - 4:40 PM
2.P2.C-4
Sub-glacial Geology of Antarctica- a preliminary investigation and results in the Grove Mountains and Vestfold Hills, East Antarctica and its tectonic implication
Yue Zhao, Shuan-Hong Zhang, Xiao-Chun Liu, Jian-Min Hu, Jian Liu, Yan-Bin Pan, Mei-Jian An, and Gang Xu. Institute of Geomechanics, Chinese Academy of Geological Sciences, 11# Min Zu Da Xue southern Road, Beijing, 100081, China
In this paper we present our recent investigation and preliminary results of erratic rocks in the Grove Mountains and the Vestfold Hills to understand the sub-glacial geology of Antarctica. Four high-pressure mafic granulite erratics from the Grove Mountains give peak metamorphism of 12.9-15.8 kb and 810-910°C at 545-542 Ma by a conventional thermometer and barometer with SHRIMP U-Pb zircon dating. It is the first report of a Pan-African high-pressure granulite facies record from inland Antarctica, key evidence for a Pan-African suture beneath the ice sheet near the Grove Mountains. Investigation and statistics of erratics in the southeast Vestfold Hills show that low-grade rocks are the majority at some localities. Analyses of the erratic rocks by ongoing zircon SHRIMP U-Pb dating and their Hf isotope as well as mineral Ar-Ar ages can enrich our knowledge of the sub-glacial geology of Antarctica, combined with glacier dynamics, sub-glacier morphology and geophysics.