Forster, Astrid; Sturt, Helen; Meyers, Philip A.; Erbacher, Jochen; Mosher, David C.; Malone, Mitchell J.; Berti, Debora; Bice, Karen L.; Bostock, Helen; Brumsack, Hans-Juergen; Danelian, Taniel; Glatz, Christine; Heidersdorf, Felix; Henderiks, Jorijntje; Janecek, Thomas R.; Junium, Christopher; Le Callonnec, Laurence; MacLeod, Ken; Mutterlose, H. Joerg; Nishi, Hiroshi; Norris, Richard D.; Ogg, James G.; O'Regan, A. Matthew; Rea, Brice; Sexton, Philip; Suganuma, Yusuke; Thurow, Juergen W.; Wilson, Paul A.; Wise, Sherwood W., Jr. (2004): Molecular biogeochemistry of Cretaceous black shales from the Demerara Rise; preliminary shipboard results from Sites 1257 and 1258, ODP Leg 207. Texas A&M University, Ocean Drilling Program, College Station, TX, United States, In: Erbacher, Jochen, Mosher, David C., Malone, Mitchell J., Berti, Debora, Bice, Karen L., Bostock, Helen, Brumsack, Hans-Juergen, Danelian, Taniel, Forster, Astrid, Glatz, Christine, Heidersdorf, Felix, Henderiks, Jorijntje, Janecek, Thomas R., Junium, Christopher, Le Callonnec, Laurence, MacLeod, Ken, Meyers, Philip A., Mutterlose, H. Joerg, Nishi, Hiroshi, Norris, Richard D., Ogg, James G., O'Regan, Matthew A., Rea, Brice, Sexton, Philip, Sturt, Helen, Suganuma, Yusuke, Thurow, Juergen W., Wilson, Paul A., Wise, Sherwood W., Jr., Chapman, Mary (editor), Peters, Lorri L. (editor), Proceedings of the Ocean Drilling Program; Demerara Rise; equatorial Cretaceous and Paleogene paleoceanographic transect, western Atlantic; covering Leg 207 of the cruises of the drilling vessel JOIDES Resolution; Bridgetown, Barbados, to Rio de Janeiro, Brazil; Sites 1257-1261; 11 January-6 March 2003, 207, georefid:2004-051324

Abstract:
Shipboard analysis was carried out on the free biomarker fraction of total lipid extracts of 10 Cretaceous black shale samples from Sites 1257 and 1258. The principal aim of the investigation was to study the primary biological sources and the thermal maturity of the organic matter in the core samples as well as the conditions of its preservation. The samples have total organic carbon contents of 4.5-28 wt%. Molecular analysis of biomarkers focused on n-alkane, sterane, and pentacyclic triterpane biomarkers. The organic matter in the black shales is thermally immature and dominantly derived from algal and microbial sources with varying contributions of higher plant material. Sulfur incorporation into organic matter is evident from the abundance of hopanoid thiophenes and isorenieratane thianes. High yields of lycopane relative to n-C35 indicate that the preservation of organic matter is excellent, which is consistent with deposition under oxygen-depleted conditions in the background of low sedimentation rates.
Coverage:
West: -54.4400 East: -54.2030 North: 9.2712 South: 9.2600
Relations:
Expedition: 207
Site: 207-1257
Site: 207-1258
Supplemental Information:
Available only on CD-ROM in PDF format and on the Web in PDF or HTML
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.ir.207.110.2004 (c.f. for more detailed metadata)
Data download: application/pdf
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