Cretaceous stratigraphy of Antarctica and its global significance

Abstract

The Cretaceous period is particularly well represented by a thick sequence of clastic sedimentary rocks exposed in the Antarctic Peninsula region of western Antarctica. This was an active margin throughout the Late Mesozoic and in total some 7km+ of Cretaceous sedimentary rocks accumulated in a series of fore-, intra-, and back-arc basins. The Fossil Bluff Group of eastern Alexander Island can be traced from the Jurassic - Cretaceous boundary into the Upper Albian and represents a broad-scale shallowing-upwards sequence from deep marine to a prominent Upper Albian fluvial interval in which high density forests developed at a palaeolatitude of 75°S. The Cretaceous sequence exposed in the James Ross Island group continues right through the Upper Cretaceous to the K–Pg boundary. The Campanian - Maastrichtian succession in particular is over 2km in total thickness and richly fossiliferous. The improved Cretaceous stratigraphy of Antarctica is an invaluable terrestrial record of climatic change at a high palaeolatitude. This includes a gradual increase in temperature to the Cretaceous Thermal Maximum, and then a decline to the K–Pg boundary. There may be no simple link between these palaeotemperature changes and Cretaceous patterns of biotic radiation and extinction.