Moho-depth and subglacial sedimentary layer thickness in the Wilkes Basin from Receiver Function Analysis

Chile

Wilkes Basin lies to the east of the Transantarctic Mountains. The origin of this sub-glacial basin is still controversial. Flexural uplift of the Transantarctic Mountains has been suggested as the geophysical process which generated the basin (Stern & ien Brink, 1989). Other studies proposed a continental rift structure for this region (Ferraccioli et al., 2001). The two models differ mainly in the crustal structure predicted beneath the basin. In the former, crustal thickning is expected to be originated from the high rigidity of the East Antarctic Craton lithosphere. Otherwise, the rift structure hypothesis is consistent with a broad crustal thinning. During the WIBEM 2003 campaign, we deployed five broadband seismic stations across the basin. We selected high signal/noise teleseismic recording to compute a data-set of receiver functions. We applied a classical inversion scheme, the Neighbourhood Algorithm, to our data-set. Here, two different and complementary studies are presented. We constrain the Moho geometry beneath the Wilkes Basin from the analysis of low-frequency P-to-S conversion at the base of the crust. Also, we investigate the nature of the basin mapping the presence of subglacial sediments using the P-to-S conversion at the ice-bedrock interface.