CaltechAUTHORS
  A Caltech Library Service

Carbon isotopes and lipid biomarkers from organic-rich facies of the Shuram Formation, Sultanate of Oman

Lee, C. and Fike, D. A. and Love, G. D. and Sessions, A. L. and Grotzinger, J. P. and Summons, R. E. and Fischer, W. W. (2013) Carbon isotopes and lipid biomarkers from organic-rich facies of the Shuram Formation, Sultanate of Oman. Geobiology, 11 (5). pp. 406-419. ISSN 1472-4677. doi:10.1111/gbi.12045. https://resolver.caltech.edu/CaltechAUTHORS:20130917-102929781

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20130917-102929781

Abstract

The largest recorded carbon isotopic excursion in Earth history is observed globally in carbonate rocks of middle Ediacaran age. Known from the Sultanate of Oman as the ‘Shuram excursion’, this event records a dramatic, systematic shift in δ^(13)C_(carbonate) values to ca. −12‰. Attempts to explain the nature, magnitude and origin of this excursion include (i) a primary signal resulting from the protracted oxidation of a large dissolved organic carbon reservoir in seawater, release of methane from sediment-hosted clathrates, or water column stratification; and (ii) a secondary signal from diagenetic processes. The compositions and isotope ratios of organic carbon phases during the excursion are critical to evaluating these ideas; however, previous work has focused on localities that are low in organic carbon, hindering straightforward interpretation of the observed time-series trends. We report carbon isotope data from bulk organic carbon, extracted bitumen and kerogen, in addition to lipid biomarker data, from a subsurface well drilled on the eastern flank of the South Oman Salt Basin, Sultanate of Oman. This section captures Nafun Group strata through the Ediacaran–Cambrian boundary in the Ara Group and includes an organic-rich, deeper-water facies of the Shuram Formation. Despite the high organic matter contents, the carbon isotopic compositions of carbonates – which record a negative δ^(13)C isotope excursion similar in shape and magnitude to sections elsewhere in Oman – do not covary with those of organic phases (bulk TOC, bitumen and kerogen). Paired inorganic and organic δ^(13)C data only display coupled behaviour during the latter part of the excursion's recovery. Furthermore, lipid biomarker data reveal that organic matter composition and source inputs varied stratigraphically, reflecting biological community shifts in non-migrated, syngenetic organic matter deposited during this interval.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1111/gbi.12045 DOIArticle
http://onlinelibrary.wiley.com/doi/10.1111/gbi.12045/abstractPublisherArticle
ORCID:
AuthorORCID
Fike, D. A.0000-0003-2848-0328
Love, G. D.0000-0002-6516-014X
Sessions, A. L.0000-0001-6120-2763
Grotzinger, J. P.0000-0001-9324-1257
Summons, R. E.0000-0002-7144-8537
Fischer, W. W.0000-0002-8836-3054
Additional Information:© 2013 John Wiley & Sons Ltd. Received 28 January 2013; accepted 24 May 2013. Article first published online: 20 Jun. 2013. We acknowledge the Agouron Institute for supporting this work, Petroleum Development Oman for access to subsurface materials and Kristin Bergmann for helpful comments. Additionally, we acknowledge editors Roger Buick and Kurt Konhauser for handling the manuscript and constructive comments provided by three anonymous reviewers.
Funders:
Funding AgencyGrant Number
Agouron InstituteUNSPECIFIED
Issue or Number:5
DOI:10.1111/gbi.12045
Record Number:CaltechAUTHORS:20130917-102929781
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130917-102929781
Official Citation:Lee, C., Fike, D. A., Love, G. D., Sessions, A. L., Grotzinger, J. P., Summons, R. E. and Fischer, W. W. (2013), Carbon isotopes and lipid biomarkers from organic-rich facies of the Shuram Formation, Sultanate of Oman. Geobiology, 11: 406–419. doi: 10.1111/gbi.12045
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41362
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:17 Sep 2013 19:48
Last Modified:10 Nov 2021 04:29

Repository Staff Only: item control page