Early paleozoic history of the central transantarctic mountains: evidence from the Holyoake Range, Antarctica

Abstract

Abstract New stratigraphic observations within the Byrd Group of the northern Holyoake Range show, that Paleozoic sedimentation commenced in this part of East Antarctica by at least middle Early Cambrian (Atdabanian) time, and that a carbonate platform existed during much of the remainder of the Early Cambrian. The later tectonic history of this sector of the central Transantarctic Mountains, however, is more complex than it was formerly thought to be. At least two episodes of deformation, rather than the one previously recognised, affected the Paleozoic rocks prior to deposition of the basal beds of theBeacon Supergroup during the Devonian. We illustrate the first documented in situ Lower Cambrian trilobites collected from the continent. They were recovered from the lowest unit of the Byrd Group, the Shackleton Limestone. This limestone, here thought to be considerably thinner than the 5400 m thickness previously inferred for it, was strongly deformed and subsequently overlain with angular unconformity b...