Abstract
This study presents the results of forward numerical models of a series of sections of the Aurora Trench (East Antarctica) derived from radio echo-sounding data that allowed to reconstruct the 3D shape of the Aurora Fault, a crustal listric normal fault characterized by a length exceeding 100 km. A similar extensional fault setting allows to replicate the asymmetric buried morphology of the magnetic basement at the Lake Vostok depression derived by the available gravity and magnetic profiles. Both the Aurora and Vostok listric fault reach their basal decollment at 34 km depth, possibly the base of the crust in this intracratonic environment. Integration of these results with the existing geologic interpretations of the tectonic origin of the Concordia Trench by normal faulting allowed to frame the Concordia, Aurora and Vostok normal faults within an intraplate transtensional corridor with a left-lateral movement component. The westward projection of the proposed strike-slip deformation belt may develop in correspondence of an older tectonic lineament stretching from the Eastern flanks of the Gamburtsev Subglacial Mts to the Lambert rift and characterized by a poly-phased complex tectonic history. The possible Cenozoic reactivation of these structures is discussed in the paper.
Highlights
The Antarctic plate has a unique geodynamic setting since it is almost completely surrounded by divergent or conservative margins, with the limited exception of the subduction zones of South Sandwich and South Shetland Islands [1,2]
Results from the forward numerical modelling of radio echo-sounding (RES) data in the Vostok and Dome C region address a series of issue about the geologic setting of the inner part of the East Antarctic Craton (EAC)
The modelling allowed reconstructing the 3D geometry of this regional tectonic lineament of the ice-buried bedrock
Summary
The Antarctic plate has a unique geodynamic setting since it is almost completely surrounded by divergent or conservative margins, with the limited exception of the subduction zones of South Sandwich and South Shetland Islands [1,2]. The East Antarctic Ice Sheet (EAIS) prevents the direct analysis of the subglacial geology and landscape, leaving most of the geologic information derived from geophysical investigations. It is widely acknowledged that the subglacial geological setting controls the ice sheet dynamics that in turn influence polar climate changes during Cenozoic times as the Drake Passage opening and the drifting from Australia [12,13,14,15,16]. The feedback mechanisms between climate, buried landscape and geodynamic processes challenge the developments of new original approaches to unravel the Cenozoic tectonic evolution of the East Antarctic Craton (EAC). In this way the Scientific Committee for Antarctic Research promotes interdisciplinary research projects (ACE, SALE, ACGS, AGAP Projects)
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