Distributions of C-22-C-30 even-carbon-number n-alkanes in ocean anoxic event 1 samples from the Basque-Cantabrian Basin

Chaler, R. and Dorronsoro, C. and Grimalt, J. O. and Agirrezabala, L. M. and Fernandez-Mendiola, P. A. and Garcia-Mondejar, J. and Gomez Perez, I. and Lopez-Horgue, M. (2005) Distributions of C-22-C-30 even-carbon-number n-alkanes in ocean anoxic event 1 samples from the Basque-Cantabrian Basin. Naturwissenschaften, 92 (5). pp. 221-225. DOI 10.1007/s00114-005-0616-2

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Abstract

The Ocean Anoxic Event 1 (OAE-1) in central sites of the Basque-Cantabrian Basin exhibits very reducing depositional conditions of sedimentation. These sedimentation events have left a distinct mixture of hydrocarbons that are represented by C22-C30 n-alkanes with a predominance of the even-carbon-number homologues, high relative proportions of squalane and C16-C24 n-alkylcyclopentanes predominated by n-undecyl-, n-tridecyl- and n-pentadecylcyclopentane. Other minor compounds encompass a series of C18-C21 n-alkylcyclohexanes and C18-C24 dimethyl n-alkylcyclohexanes maximized by the even-carbon-number homologues as well as iso- and anteiso-alkanes. This unusual distribution of n-alkanes in this environment provides a new case for comparison with previously reported hypersaline and phosphorite sedimentary deposits where the occurrence of similar n-alkane distributions was reported. In the present case, these major n-alkanes and squalane are indicative of transformation under strong reducing conditions. In contrast, the occurrence of the alkylcyclopentanes, irrespective of the presence of even-carbon-number n-alkanes or squalane, suggests that reductive cyclization of fatty acids is less dependent on strong reducing conditions.

Item Type:	Article
Uncontrolled Keywords:	2005 AREP 2005 P IA48 CASP
Subjects:	05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Divisions:	05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Journal or Publication Title:	Naturwissenschaften
Volume:	92
Page Range:	pp. 221-225
Identification Number:	10.1007/s00114-005-0616-2
Depositing User:	Sarah Humbert
Date Deposited:	12 Aug 2011 10:26
Last Modified:	23 Jul 2013 09:58
URI:	http://eprints.esc.cam.ac.uk/id/eprint/1598

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