| Title: | Cretaceous tectonic events and their influences on ocean circulation |
| Author: | Lawrence A Lawver |
| Date Submitted: | 05/09/2002 |
| Address: | Institute for Geophysics
4412 Spicewood Springs Road #600
Austin
TX
USA
78759-8500
|
| Phone: | +1-512-471-0433 |
| Email: | lawver@ig.utexas.edu |
| Co-Authors: | Gahagan, Lisa M., plates@ig.utexas.edu |
| Affiliation: | University of Texas at Austin, Institute for Geophysics |
| | |
| Abstract URL: | http://cis.whoi.edu/science/GG/ccod/viewAbstracts.cfm?RefNumber=19725640 |
| Author Project webpage: | http://www.ig.utexas.edu/research/projects/plates/plates.htm |
| Keywords: | Plate motions, Gateways, South Atlantic, Arctic |
| Abstract: | Prior to the Jurassic break-up of Gondwana, there was one global ocean, the Pacific Ocean. By the earliest Cretaceous, a circum-tropical seaway opened, extending from the Tethys region between Africa and Iberia into the Central Atlantic between North America and Africa. Throughout the Cretaceous, the Central Atlantic widened while the Tethyean region had a number of small plates and blocks that may have intermittantly impeded circulation through it. Even though the South Atlantic initially rifted at the time of the Parana mantle plume [~132 Ma], deep circulation was restricted by a number of barriers until much later. One such barrier, the Falkland Plateau, did not clear Africa until ~105 Ma leading to extensive salt deposits in the South Atlantic. Astrid Ridge, Maud Rise and the Mozambique Plateau probably formed an effective barrier to deep circulation between the Indian Ocean and the South Atlantic until after 100 Ma. One of the significant tectonic events during the Cretaceous was the opening of the Amerasian Basin of the Arctic Ocean. Opening is thought to have initiated during the Late Neocomian and was complete by the Aptian. It is conceivable that the Arctic Ocean as an isolated basin may have been responsible for the short term sealevel drop near the beginning of the Aptian on the recalibrated sealevel curve. Sudden flooding of other isolated basins, such as the South Atlantic and the Mesozoic Weddell Sea, may explain earlier Neocomian sealevel drops. An animation of the development of the Cretaceous oceans will be shown while opening of circulation gateways particularly into and out/of the South Atlantic will be highlighted. |
|