Influence of Early Pliocene Uplift on Late Pliocene Cooling in the Arctic-Atlantic Gateway

Jochen Knies

Despite the undisputed role of the Arctic Ocean in the modern and Pliocene climate system, the Arctic has attracted much attention only in the past few years since the public has become aware of the ongoing fundamental change in the Arctic cryosphere as a possible response to global warming. Clarification of the Arctic role in global climate during the Pliocene is, however, largely hampered by equivocal stratigraphic constraints. From a well-dated Pliocene sequence from the Yermak Plateau, NW Spitsbergen, we present sedimentological and geochemical data indicating that 4 million years ago terrigenous sediment supply and sources changed abruptly in response to a regional tectonic uplift event. We argue that this event together with the final opening of the deep-water gateway and contemporary uplift and tilting along the northwestern European continental margin preconditioned the landmasses for glacial ice build-up during intensification of the Northern Hemisphere Glaciation (INHG). Adjacent to the North Atlantic warm pool as a regional moisture source, declining atmospheric CO2 levels and other feedback mechanisms during the Pliocene, this uplift caused decreased summer ablation and thus allowed the initial build-up of glacial ice both in Scandinavia, and the sub-aerially exposed Svalbard/Barents Sea culminating in the first large scale coastline-shelf edge glaciations at ~2.74 million years ago.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013