Synsedimentary Deformation in the Permian Takrouna Fm (North Victoria Land)

(Beacon Supergroup) exposed at an unnamed spur east of Mt Remington north of Boggs Valley, central Rennick Glacier area, North Victoria Land. In the lower part of this section, the formation consists of fluvio-lacustrine successions of pebbly sandstone, climbing-ripple-laminated sand- and siltstone, and carbonaceous silt- and mudstone rich in plant debris (Glossopteris leaves and Vertebraria roots). Sand- and siltstone beds in particular are characterized by prominent synsedimentary brittle-ductile deformation structures at the outcrop scale, e.g., sedimentary dikes, thrust, growth microfaults, shear folds, normal faults, laminated convolute beds, and intense slumping. This succession is overlain by about 10 m of barren sand- and siltstone deposits that lack such evidence for synsedimentary deformation, and are instead folded and tilted by post-sedimentary deformations. Our synsedimentary tectonic structures may testify to an active tectonism during the late Permian in northern Victoria Land and give constraints for the changes in paleoclimatic and tectonic conditions of Gondwana during late Paleozoic-Mesozoic transition.