Periodic changes in the Cretaceous ocean and climate caused by marine redox see-saw.
Wallmann, Klaus , Flögel, Sascha, Scholz, Florian, Dale, Andrew W.
, Kemena, Tronje Peer
, Steinig, Sebastian
and Kuhnt, Wolfgang
(2019)
Periodic changes in the Cretaceous ocean and climate caused by marine redox see-saw.
Nature Geoscience, 12
(6).
pp. 456-461.
DOI 10.1038/s41561-019-0359-x.
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Abstract
Periodic changes in sediment composition are usually ascribed to insolation forcing controlled by Earth’s orbital parameters. During the Cretaceous Thermal Maximum at 97–91 Myr ago (Ma), a 37–50-kyr-long cycle that is generally believed to reflect obliquity forcing dominates the sediment record. Here, we use a numerical ocean model to show that a cycle of this length can be generated by marine biogeochemical processes without applying orbital forcing. According to our model, the restricted proto-North Atlantic and Tethys basins were poorly ventilated and oscillated between iron-rich and sulfidic (euxinic) states. The Panthalassa Basin was fertilized by dissolved iron originating from the proto-North Atlantic. Hence, it was less oxygenated while the proto-North Atlantic was in an iron-rich state and better oxygenated during euxinic periods in the proto-North Atlantic. This redox see-saw was strong enough to create significant changes in atmospheric pCO2. We conclude that most of the variability in the mid-Cretaceous ocean–atmosphere system can be ascribed to the internal redox see-saw and its response to external orbital forcing.
Document Type: | Article |
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Additional Information: | The UVic model and the REDBIO box model (written in MATHEMATICA) are available from S.F. (sfloegel@geomar.de) and K.W., respectively. |
Keywords: | Cretaceous, Modelling, orbital cycles, biogeochemical feedbacks, seasaw |
Research affiliation: | OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems OceanRep > SFB 754 OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology Kiel University |
Refereed: | Yes |
Open Access Journal?: | No |
DOI etc.: | 10.1038/s41561-019-0359-x |
ISSN: | 1752-0894 |
Projects: | ICONOX, SFB754 |
Date Deposited: | 22 May 2019 07:37 |
Last Modified: | 08 Feb 2021 07:39 |
URI: | http://oceanrep.geomar.de/id/eprint/46769 |
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