Title: Authors: Affiliation:
Publication: Publication Date: Origin: Keywords: Bibliographic Code:
From Greenhouse to Icehouse: Marine and Terrestrial Palynological Evidence for Climatic and Oceanic Change Through the Cenozoic of the Arctic Bujak, J. P.; Brinkhuis, H. AA(Bujak Research International, 105 North Park Drive, Blackpool, FY3 8NE United Kingdom
[email protected]), AB(Laboratory of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD Netherlands
[email protected]) American Geophysical Union, Fall Meeting 2004, abstract #PP54B-05 12/2004 AGU 9315 Arctic region, 3344 Paleoclimatology, 4267 Paleoceanography, 3030 Micropaleontology, 0400 Biogeosciences 2004AGUFMPP54B..05B Abstract
The marine and terrestrial biotas of northern Alaska and the Canadian Beaufort Mackenzie Basin (BMB) are intimately linked to changes in the climate and oceanography of the region. These changes can be reconstructed using palynological data from surface sections and numerous exploration wells drilled in the region over the past 30 years. During the Late Triassic to Early Eocene, marine dinoflagellate cyst (dinocyst) and terrestrial miospore (pollen and spore) palynomorphs were diverse and abundant across the region, reflecting the presence of a relatively warm and productive polar ocean that was fringed by extensive forests. The region was heated by northward-flowing Pacific currents, but lay north of the Arctic Circle and had seasonal 24 hour winter darkness and summer daylight. No modern analogue exists for this environment. A dramatic change occurred at the end of the Early Eocene as global climate shifted from the greenhouse towards the modern icehouse world. This had a particularly strong effect in high latitudes. A succession of major extinction events reflected falling sea and air temperatures in the Arctic and progressively eliminated marine and terrestrial species from the region. These events can be correlated with Eocene cooling steps known from the North Atlantic, where they had a milder effect, and provide a chronostratigraphic link between the regions. By Oligocene time the Arctic populations were strongly impoverished, but Miocene warming permitted the immigration of coldtemperate species including marine dinoflagellates and terrestrial angiosperms. Following this warm phase, the marine and terrestrial populations became increasingly restricted as air and water temperatures fell during the Plio-Pleistocene, leading to the modern highly endemic Arctic biotas. 1
