Crustal Structure Across Northern Victoria Land, Antarctica, From Receiver Function Analysis

Abstract

Global crustal model, from gravity studies, imaged a thick crust (>40 km) under Eastern Antartic craton (EAC). This global trend ends abruptly west of the Transantarctic Mountains (TAM), which border EAC along its western margins. There, the crust raises up to about 20 km. While this model points out the difference between EAC and the Ross sea crustal structures, its intrinsic spatial resolution gives little help to solve some regional geophysical issues, like the TAM orogenesis and the formation and nature of the Wilkes Basin. In this study, teleseismic Receiver Functions (RFs) are used to image the S-velocity crustal structure in finer details. We computed RFs from teleseismic events recorded during three different austral summer compaigns: BackTAM, WIBEM and WISE. Broadband seismic stations were deployed along a transect which spans from the coast of Northern Victoria land (NVL) to the far interior of the EAC plateau. The transect, almost perpendicular to the regional TAM axis, came across four different geological/geophysical settings: the alloctonhous terranes of the NVL, the TAM sector, the Wilkes Basin and the EAC plateau. Each area shows peculiar crustal structures and we propose both finer local S-velocity models and a regional crustal model.