The history of denudation and resedimentation at the continental margin of western Dronning Maud Land, Antarctica, during break-up of Gondwana

Abstract

A c. 500 km wide rim of the continental margin of western Dronning Maud Land was tectono-thermally affected during the Gondwana fragmentation. This has been determined by apatite fission-track dating of the basement in Heimefrontfjella and Mannefallknausane and from geomorphological aspects. The continental crust of western Dronning Maud Land was heated by the burial of 2-3 km of low conductivity Jurassic lava from c. 180Ma until the Early Cretaceous (c. 140 Ma) when the lava pile was eroded again. Early Cretaceous erosion took place in association with intense block faulting, and is in strong contrast to the sedimentation history offshore. The sedimentation on the marine plateau of western Dronning Maud Land is characterized by the deposition of 2000 m of Late Jurassic sediments at rates of >60mMa -1. This was followed by deposition in Cretaceous to Cenozoic times of a c. 1000 m thick unit at a slower rate of sedimentation. Consequently, initial rifting must have been confined to a narrow continental rift, while the advanced rift stage affected the continental margin as far inland as the Heimefrontfjella (c. 500 km). The denuded section was probably channelled through the Jutul-Penck graben to the north, and a graben system presently occupied by the Endurance Glacier to the west and must have then been disseminated in the Weddell basin without producing a distinctive sequence.