The exhumation of northern Victoria Land and consequences on the uplift of the Transantarctic Mountains

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The project aims to reconstruct the long-term landscape evolution of northern Victoria Land. The study area occupies the termination of the Transantarctic Mountains at the intersection between the Pacific Antarctic transform margin and the West Antarctic Rift System. It is composed of three terranes: the Precambrian cratonic Wilson Terrane, and the Paleozoic metasedimentary Bowers and Robertson Bay terranes. This geological division is reflected by a distinctive geomorphological contrast between elevated, deeply incised inland plateaus and an Alpine coastal morphology, and appears to correlate with considerably varying uplift and exhumation histories. Exhumation of the Wilson Terrane has been reconstructed in detail during the last years my means of thermochrono¬logical and structural data, and geomorphological observation. These data require the existence of a long-lasting Mesozoic basin in the vicinity of the present Transantarctic Mountains that was exhumed in two stages. Basin inversion and extensive denudation commenced in the Early Oligocene, followed by increased uplift, plateau formation and incision since the Miocene. The project focuses on the exhumation of the Bowers and Robertson Bay Terranes and related tectonic processes, as well as the development of the landscape contrast across northern Victoria Land. The outcome of the project will enhance substantially our knowledge about the uplift of the Transantarctic Mountains and the evolution of the West Antarctic Rift System, contribute new arguments for the interpretation of the seismic stratigraphy in the Ross Sea troughs, and improve our understanding of the system tectonics – climate – lithology. It also has first-order consequences on timing and course of Gondwana breakup between Antarctica and Australia and will provide essential background parameters for the long-term climate reconstruction of the southern hemisphere. Methodologically, the project relies on structural geology, geomorphological observation and sampling of basement, cover rocks and brittle structures during the BGR expedition GANOVEX XIII (2018/19). Subsequent thermochronological research includes fission track (FT) and (U-Th-Sm)/He analyses on apatites and zircons, followed by thermal history modelling and a three-dimensional reconstruction of the isotherm pattern of the uppermost crust.