Opening of the Amerasia Basin and its Significance for Understanding Late Palaeozoic and Mesozoic Sediment Dispersal Patterns in the Arctic
Robert A. Scott1, Jenny E. Omma1, Lester M. Anderson1, Vicky Pease2, and Stewart Sinclair3
1University of Cambridge, Cambridge, United Kingdom
2Stockholm University, Stockholm, Sweden
3CASP, University of Cambridge, Cambridge, United Kingdom
The Arctic Ocean contains two deep-water oceanic basins: the Eurasia Basin opened during Cenozoic time, with a spreading history that is well-constrained by linear magnetic anomalies; the Amerasia Basin is considered to have opened predominantly during Cretaceous time but there is no easily interpretable pattern of magnetic anomalies and, furthermore, the origins of several component features are controversial. Unsurprisingly, therefore, the mechanism responsible for opening the Amerasia Basin is disputed.
Different spreading mechanisms in the Amerasia Basin imply profoundly different geological histories for the surrounding shelves. Northerly-derived Late Palaeozoic and Mesozoic sediments are recognised in a number of Arctic basins on these shelves, necessitating sediment derivation from the area now occupied by the Arctic Ocean. As a consequence, a central Arctic landmass has been depicted on many palaeogeographic reconstructions prior to opening of the Arctic Ocean. However, because pieces of this former landmass (or landmasses) are now fragmented around the margins of the Arctic Ocean, their pre-drift configuration can only be truly understood when spreading geometries for the Amerasia Basin are properly constrained. Conversely, the ability to identify and characterise the component pieces of a pre-drift central Arctic landmass will provide data with which to refine Arctic Ocean spreading models. Here we report research that seeks to combine geophysical studies of the Amerasia Basin with provenance analysis of northerly-derived clastic sediment on surrounding shelves in an attempt to provide these constraints.
AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece