Intraplate Transtensional Tectonics in the East Antarctic Craton: Insight from Buried Subglacial Bedrock in the Lake Vostok—Dome C Region

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 reconstructing 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 replicating 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 framing 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.

Lineament Domain of Regional Strike-Slip Corridor: Insight from the Neogene Transtensional De Geer Transform Fault in NW Spitsbergen

“…The found en-echelon spatial distribution along a NW-SE trend indicates that this extension may be the result of the activity of a parallel tectonic feature at the larger regional scale (CIANFARRA and SALVINI 2013b). This element can easily be responsible for the localized extension, assuming that it has a right-lateral shear component (Fig.…”

Ice sheet surface lineaments as nonconventional indicators of East Antarctica bedrock tectonics

“…The two azimuthal frequency analyses are graphically presented as wind rose frequency diagrams and as gray shades in a graphic table (Fig. 2) to aid the comparison between lineament domain azimuths and the directions of the main known morphotectonic features of the bedrock in the study region (Lake Vostok, the Aurora and Concordia Trenches, and the Adventure Basin; Drewry, 1976;Ferraccioli et al, 2001Ferraccioli et al, , 2009Studinger et al, 2003;Forieri et al, 2004;Tabacco et al, 2006;Cianfarra et al, 2009aCianfarra et al, , 2009bCianfarra and Salvini, 2013;Fretwell et al, 2013;Jordan et al, 2013). The adopted azimuth convention in the rose diagrams and graphic table refers to a false northing (FN) parallel to the y axis of the analyzed images, and azimuths are indicated with the prefi x FN.…”

“…The right-side border of the Adventure domain, toward the ice divide, is characterized by a saw-tooth shape. This geometry may relate to the en echelon pattern of the tectonic subglacial depressions in the Vostok-Dome C-Adventure Basin region that form a subcontinental left-lateral strike-slip corridor, where the local extension conditions are compatible with listric normal faulting responsible for the formation of the elongated depressions (Forieri et al, 2004;Tabacco et al, 2006;Cianfarra et al, 2009aCianfarra et al, , 2009bCianfarra and Salvini, 2013).…”

“…The comparison shows that lineaments are not affected by changes in the directions of the wind fi eld. Given the correlation between Radarsat lineament domains and the tectonic setting of the investigated area, a more reliable hypothesis is to consider ice surface lineaments as the effect of the interaction between ice dynamics and bedrock morphology, that in turn relates to tectonics (Forieri et al, 2004;Tabacco et al, 2006;Cianfarra et al, 2009a;Cianfarra and Salvini, 2013).…”

“…Their morphology has been related to the tectonic activity of crustal, listric faults in either extensional (Leitchenkov et al, 1999;Ferraccioli et al, 2001;Cianfarra et al, 2009aCianfarra et al, , 2009b or compressional geodynamic settings (Studinger et al, 2003(Studinger et al, , 2004. Proposed ages of tectonic activity span from Proterozoic (Aitken et al, 2014) and Paleozoic (Dalziel, 1998;Leitchenkov et al, 1999;Studinger et al, 2003) to Cenozoic (Tabacco et al, 2006;Cianfarra et al, 2009aCianfarra et al, , 2009bCianfarra and Salvini, 2013).…”