The subglacial geology of Wilkes Land, East Antarctica

Abstract

Wilkes Land is a key region for studying the configuration of Gondwana and for appreciating the role of tectonic boundary conditions on East Antarctic Ice Sheet (EAIS) behavior. Despite this importance, it remains one of the largest regions on Earth where we lack a basic knowledge of geology. New magnetic, gravity, and subglacial topography data allow the region's first comprehensive geological interpretation. We map lithospheric domains and their bounding faults, including the suture between Indo-Antarctica and Australo-Antarctica. Furthermore, we image subglacial sedimentary basins, including the Aurora and Knox Subglacial Basins and the previously unknown Sabrina Subglacial Basin. Commonality of structure in magnetic, gravity, and topography data suggest that pre-EAIS tectonic features are a primary control on subglacial topography. The preservation of this relationship after glaciation suggests that these tectonic features provide topographic and basal boundary conditions that have strongly influenced the structure and evolution of the EAIS.

Crustal heat production and estimate of terrestrial heat flow in central East Antarctica, with implications for thermal input to the East Antarctic ice sheet

“…As a group they are distinctly different from the regional pattern shown by anomalously warm Proterozoic crust in central Australia with average q o = 80 mW m −2 (McLaren et al, 2003), which has been suggested to extend across the Wilkes Land margin of Antarctica based on Gondwana supercontinent reconstructions (Carson et al, 2014;Aitken et al, 2014). Despite general age similarities among some of the clast population with parts of the Gawler Craton, and basement age correlations that indicate continuity of Mawson-type crust into the Wilkes sector of East Antarctica (Goodge and Fanning, 2016), the proxy heat production determinations and heat flow estimates provided here suggest that central portions of the East Antarctic ice sheet are underlain by stable continental crust with quite normal thermal properties represented by average values of heat production of about 2.5 µW m −3 and heat flow of about 50 mW m −2 .…”

“…Compared to examples globally (Mareschal and Jaupart, 2013;Jaupart et al, 2016;Artemieva et al, 2017), the Proterozoic igneous rocks in this study indicate that heat production in central East Antarctica is like that of typical www.the-cryosphere.net/12/491/2018/ The Cryosphere, 12, 491-504, 2018 continental shield areas and demonstrably different from the anomalously warm region represented by the CAHFP. Geological and geophysical correlations between cratonic rocks in southern Australia (Gawler craton) and the Wilkes Land region of East Antarctica (e.g., Oliver and Fanning, 1997;Aitken et al, 2014;Goodge and Finn, 2010;Boger, 2011;Fanning, 2010, 2016), have been used as the basis for extrapolating high heat flow values reported for the CAHFP into East Antarctica (Carson et al, 2014). To date, no direct constraint on terrestrial heat flow has been provided for this area of Wilkes Land, and how far south toward Dome C and the upper Aurora and Wilkes subglacial basins this province may extend is not clear.…”

Exploring the Recovery Lakes region and interior Dronning Maud Land, East Antarctica, with airborne gravity, magnetic and radar measurements

“…The ICEGRAV magnetic data provide a new geophysical tool with which to study the largely unknown tectonic architecture of this region, thereby augmenting previous exploration efforts in other parts of East Antarctica (e.g. Aitken et al 2014), and also to investigate geological boundary conditions and their influence on ice stream dynamics in interior Dronning Maud Land and Coats Land (e.g. Shepherd et al 2006).…”

The Australo-Antarctic Columbia to Gondwana transition

“…We use aeromagnetic and aerogravity data collected during the 2009-2013 ICECAP field program, as described in Aitken et al (2014). This survey covers a region from 90°E to 150°E and extends from the coast up to 1000 km into the continental interior.…”

“…Recent geochronological and isotopic studies in central and western Australia Kirkland et al, 2011Kirkland et al, , 2013Smits et al, 2014;Spaggiari et al, 2014) suggest a significantly more complicated evolution than earlier models, but the geometrical framework to understand this complexity has been lacking. The transition from Rodinia-era configuration to the Gondwana-era configuration is better resolved (Cawood, 2005;Boger, 2011), however, there still remains significant uncertainty regarding the timing and nature of events, especially in Antarctica (cf Boger, 2011;Harley et al, 2013;Aitken et al, 2014).…”