A ~9myr cycle in Cenozoic δ13C record and long-term orbital eccentricity modulation: Is there a link?
Boulila, Slah, Galbrun, Bruno, Laskar, Jacques and Pälike, Heiko (2012) A ~9myr cycle in Cenozoic δ13C record and long-term orbital eccentricity modulation: Is there a link? Earth and Planetary Science Letters, 317-318, 273-281. (doi:10.1016/j.epsl.2011.11.017).
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The ~ 65-myr-long Cenozoic carbon isotope record (δ13C) of Zachos et al. (2001, 2008) documents a strong long-term cycle with a mean pseudoperiodicity close to ~ 9 myr. This cyclicity modulates the ~ 2.4 myr eccentricity cycle amplitude, hinting at a possible link between long-term astronomical and geological variations. Some phase shifts between ~ 9-myr δ13C and astronomical cycles suggest that additional processes (e.g., tectonics) contribute to these long-term carbon-cycle variations.
The strong response of δ13C to long-term eccentricity periods (~ 9 myr, ~ 2.4 myr, ~ 400 kyr) supports the hypothesis that the long time-residence of carbon in the oceans amplifies lower frequency or dampens higher frequency orbital variations. Additionally, the strong expression of low-amplitude ~ 9 myr eccentricity cycle in the δ13C record could be explained by energy-transfer process from higher to lower frequency cycles, and all eccentricity components modulate the carrier climatic precession cycles.
Finally, the Paleocene–Eocene Thermal Maximum (PETM, 55.9 Ma) event, which corresponds to a pronounced δ13C negative excursion, is situated within a strong decrease in the most prominent ~ 9 myr δ13C cycle, hinting at a link between accelerated rates in δ13C variations and the PETM. This specific ~ 9 myr δ13C cycle seems to be amplified by non-orbital mechanisms in atmosphere–continent–ocean system, such as previously suggested methane release from gas hydrate and volcanism.
|Keywords:||cenozoic deep-sea δ13C records; multi-millionyear cyclicity; ~ 9 myr cyclicity; astronomical driving force; eccentricity|
|Subjects:||G Geography. Anthropology. Recreation > GC Oceanography|
|Divisions:||Faculty of Natural and Environmental Sciences > Ocean and Earth Science > Palaeoceanography & Palaeoclimate
|Date Deposited:||13 Apr 2012 14:31|
|Last Modified:||02 Nov 2012 11:39|
|Contributors:||Boulila, Slah (Author)
Galbrun, Bruno (Author)
Laskar, Jacques (Author)
Pälike, Heiko (Author)
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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