Revised stratigraphy, timing, and amplitude of the middle Miocene eustatic sea-level fall recorded on the Marion Plateau, Northeastern Australia (ODP Leg 194)
Abstract
Carbonate sequences of the Marion Plateau of northeast Australia (ODP Leg 194) have been critical in reconstructing the amplitude of the middle Miocene sea-level fall. Here, we present a revised stratigraphic framework for the Marion Plateau based on correlating drilling sites along the slope using core and downhole log data, and tying the platform to the slope sequences using recently published Sr isotope data. The new stratigraphic framework is significantly different from the shipboard results, which prompts us to reevaluate the estimate of the magnitude of the eustatic sea-level fall based on backstripping of the Marion Plateau sequences. Because correlation between the upper slope and distal slope sites is significantly improved, we can now use the relatively well-constrained age model of the distal slope to date critical sequences on the upper slope. Preliminary results show that the lowstand interval is characterized by condensed depositional facies, probably triggered by a reduction in the carbonate factory during eustatic lowstands. Furthermore, we show that the middle Miocene "lowstand" recorded by the Marion Plateau is a composite of several phases of successive sea-level falls, spanning the 13.5-11.7 Ma interval (oxygen isotope events Mi3, Mi4, and Mi5).
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFMPP51B0478J
- Keywords:
-
- 1641 Sea level change (1222;
- 1225;
- 4556);
- 3002 Continental shelf and slope processes (4219);
- 3022 Marine sediments: processes and transport;
- 3036 Ocean drilling;
- 4870 Stable isotopes (0454;
- 1041)