Obliquity Pacing of Changes in Climate and Carbon Cycling During the Eocene `Greenhouse'
Abstract
In comparison to our understanding of the Pleistocene `icehouse', the stability of climate and carbon cycling during the Eocene `greenhouse' is almost entirely unknown. This gap in understanding is particularly pronounced across the early to middle Eocene boundary, which is essentially a global hiatus. Here we present high-resolution records of deep ocean temperature, carbon cycling and seafloor dissolution from the equatorial Atlantic using the first continuous, expanded deep ocean sedimentary sections across this boundary. We find a strong coupling between deep ocean temperature and carbon cycling. The existence of a number of extreme, transient events suggests that instability was an inherent feature of Eocene climate and carbon cycling. The dominant frequency in temperature and carbon cycle variance is 41,000-year (obliquity), which demonstrates the durability of the obliquity cycle in pacing environmental change even in the absence of the amplifying effect of polar ice sheets. The presence of a strong obliquity signal in the Eocene equatorial Atlantic also suggests that pervasive climatic instability was a global feature of warmer-than-modern `greenhouse' regimes.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMPP22B..01S
- Keywords:
-
- 1041 Stable isotope geochemistry (0454;
- 4870);
- 4901 Abrupt/rapid climate change (1605);
- 4910 Astronomical forcing;
- 4930 Greenhouse gases;
- 4944 Micropaleontology (0459;
- 3030)