Paleoproductivity During the Mid Miocene Climate Transition
Abstract
The 16-14 Ma interval of the mid-Miocene is characterized by a period of relative warmth and the highest benthic and planktic foraminiferal δ13C values since the Paleocene. The mid Miocene period of relative warmth is followed by a major step in Antarctic ice sheet expansion at 14 Ma and a shift toward lower foraminiferal δ13C values. Here we investigate the relationship between benthic foraminiferal δ13C values, paleoproductivity, and climate change for a time interval encompassing the mid Miocene (19-11 Ma). We present results from three ODP sites located in the Atlantic Ocean (Sites 608, 925, and 1265). Results indicate that productivity derived from benthic foraminiferal accumulation rates increases at all three sites between 17.5 Ma and 13.5 Ma paralleling the general trend of increasing foraminiferal δ13C records. We find highest export productivity (2-3 times modern values) during δ13C maxima. After the δ13C maximum at 14 Ma and the major step in Antarctic ice sheet growth, foraminiferal δ13C values decrease, but productivity continues to increase until 11 Ma the top of the investigated time interval. These observations suggest that different factors involving marine as well as terrestrial reservoirs of carbon must be considered when placing the results into the context of global carbon cycling and climate change.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMPP21B1683D
- Keywords:
-
- 0428 Carbon cycling (4806);
- 3344 Paleoclimatology (0473;
- 4900);
- 4900 PALEOCEANOGRAPHY (0473;
- 3344);
- 4944 Micropaleontology (0459;
- 3030)