Naturwissenschaften

, Volume 92, Issue 5, pp 221–225

Distributions of C22–C30 even-carbon-number n-alkanes in Ocean Anoxic Event 1 samples from the Basque-Cantabrian Basin

  • R. Chaler
  • C. Dorronsoro
  • J. O. Grimalt
  • L. M. Agirrezabala
  • P. A. Fernández-Mendiola
  • J. García-Mondejar
  • I. Gómez-Pérez
  • M. López-Horgue
Short Communication

DOI: 10.1007/s00114-005-0616-2

Cite this article as:
Chaler, R., Dorronsoro, C., Grimalt, J.O. et al. Naturwissenschaften (2005) 92: 221. doi:10.1007/s00114-005-0616-2

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.

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • R. Chaler
    • 1
  • C. Dorronsoro
    • 2
  • J. O. Grimalt
    • 1
  • L. M. Agirrezabala
    • 3
  • P. A. Fernández-Mendiola
    • 3
  • J. García-Mondejar
    • 3
  • I. Gómez-Pérez
    • 4
  • M. López-Horgue
    • 3
    • 5
  1. 1.Institute of Chemical and Environmental Research (CSIC)BarcelonaSpain
  2. 2.Department of GeologyCollege of Chemistry, University of the Basque CountryDonostia-San SebastianSpain
  3. 3.Department of Stratigraphy and PaleontologyCollege of Sciences, University of the Basque CountryBilbaoSpain
  4. 4.CASP, Earth Sciences DepartmentUniversity of CambridgeCambridgeUK
  5. 5.Department of Mines EngineeringUniversity of the Basque Country, School of Mines and Public Works Engineering, Colina de BeurkoBarakaldoSpain