New insights into the subglacial geology of the remote interior of Western Wilkes Land, East Antarctica

Western Wilkes Land, together with conjugate parts of southern Australia, records poorly-understood tectonic events that led to the amalgamation of the Proterozoic supercontinents Columbia and Rodinia. However, due to the lack of geological data in Antarctica, the tectonic architecture of western Wilkes Land remains largely unknown and only inferred from plate reconstructions.

In recent years, onshore aerogeophysical data over Wilkes Land revealed the presence of large-scale basement provinces and extensive sedimentary basins and permits better resolution of Australo-Antarctic links. Here we present a novel application of new and recently published Australian and Antarctic geological data to identify the age and character of the inaccessible crystalline basement and sedimentary cover of western Wilkes Land. We reinterpret aeromagnetic data from the conjugate Australo-Antarctic margin in the light of recent isotopic studies in southern Australia. We suggest that granitic basement similar in age and composition to the three magmatic supersuites that characterise the Coompana Province in southern Australia (c. 1600-1500 and 1200 Ma) is present in western Wilkes Land. In addition, zircon and monazite isotopic data from the first sandstone erratic rocks inferred to sample the Sabrina Subglacial Basin that covers a large part of western Wilkes Land suggest that parts of this basin may be comparable to the Neoproterozoic Officer Basin of Australia, sourcing Coompana-type crust.

Our improved knowledge of subglacial geology in western Wilkes Land will greatly inform future studies seeking to better resolve the tectonic processes that controlled the Proterozoic evolution of Columbia and Rodinia.