Constraints on the evolution of the Tasman Gateway from the Cascade Seamount, East Tasman Plateau
Abstract
The opening of the Tasman Seaway, as Tasmania, Australia finally separated from Antarctica during the Late Eocene, is thought to be one of the key tectonic events enabling the onset of the Antarctic Circumpolar Current. However, the exact mechanism enabling the onset of the Antarctic Circumpolar Current through the Tasman Gateway remains controversial. Proposed mechanisms for include Late Eocene (35-30 Ma) widening and rapid deepening, or northward migration of the gateway enabling the onset of eastward flow 30 Ma.
Here, we relook at the evolution of the Tasman Gateway in the light of new geological (dredged volcanic and volcaniclastic rocks) and geophysical (swath bathymetry) data obtained from the Cascade Seamount. The Cascade Seamount sits atop the East Tasman Plateau, immediately adjacent to ODP site 1172, where one of the more complete records of sedimentation through the key Late Eocene-Early Oligocene was recovered. We present alternative subsidence models for the East Tasman Plateau based on the age, morphology, and geochemistry of the Cascade Seamount and present a revised oceanographic and tectonic framework to explain the observed patterns of Late Eocene to Early Oligocene sedimentation in the Tasman Gateway region.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMPP11C1261W
- Keywords:
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- 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCESDE: 1635 Oceans;
- GLOBAL CHANGEDE: 4299 General or miscellaneous;
- OCEANOGRAPHY: GENERALDE: 4962 Thermohaline;
- PALEOCEANOGRAPHY