Organic matter accumulation, sulfate reduction, and methanogenesis in Pliocene-Pleistocene turbidites on the Iberia abyssal plain

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doi: 10.2973/odp.proc.sr.149.258.1996
Author(s): Meyers, Philip A.; Shaw, Timothy J.
Author Affiliation(s): Primary:
University of Michigan, Department of Geological Sciences, Ann Arbor, MI, United States
Other:
Rice University, United States
Ocean Drilling Program, United States
Université Pierre et Marie Curie, France
Dalhousie University, Canada
Universidad de Granada, Spain
Université de Nantes, France
Florida State University, United States
Universidade de Aveiro, Portugal
INTERGEOS, Netherlands
University of Waterloo, Canada
Lamont-Doherty Earth Observatory, United States
University of Tokyo, Japan
GEOMAR, Federal Republic of Germany
University of Leicester, United Kingdom
University of Texas at El Paso, United States
University of Michigan, United States
Universität Kiel, Federal Republic of Germany
Cornell University, United States
California State University, United States
Iowa State University, United States
University of Maryland System, United States
Open University, United Kingdom
University of California, United States
University of South Carolina, United States
Volume Title: Proceedings of the Ocean Drilling Program; scientific results, Iberia abyssal plain; covering Leg 149 of the cruises of the Drilling Vessel JOIDES Resolution; Balboa Harbor, Panama, to Lisbon, Portugal; sites 897-901, 10 March-25 May 1993
Volume Author(s): Whitmarsh, Robert B.; Sawyer, Dale S.; Klaus, Adam; Beslier, Marie-Odile; Collins, Eric S.; Comas, María Carmen; Cornen, Guy; de Kaenel, Eric; Pinheiro, Luis de Menezes; Gervais, Elisabeth; Gibson, Ian L.; Harry, Dennis L.; Hobart, Michael A.; Kanamatsu, Toshiya; Krawcyzk, Charlotte M.; Liu, Li; Lofts, Jeremy C.; Marsaglia, Kathleen M.; Meyers, Philip A.; Milkert, Doris; Milliken, Kitty L.; Morgan, Julia K.; Ramirez, Pedro; Seifert, Karl E.; Shaw, Timothy J.; Wilson, Chris; Yin, Chuan; Zhao, Xixi
Source: Proceedings of the Ocean Drilling Program; scientific results, Iberia abyssal plain; covering Leg 149 of the cruises of the Drilling Vessel JOIDES Resolution; Balboa Harbor, Panama, to Lisbon, Portugal; sites 897-901, 10 March-25 May 1993, Robert B. Whitmarsh, Dale S. Sawyer, Adam Klaus, Marie-Odile Beslier, Eric S. Collins, María Carmen Comas, Guy Cornen, Eric de Kaenel, Luis de Menezes Pinheiro, Elisabeth Gervais, Ian L. Gibson, Dennis L. Harry, Michael A. Hobart, Toshiya Kanamatsu, Charlotte M. Krawcyzk, Li Liu, Jeremy C. Lofts, Kathleen M. Marsaglia, Philip A. Meyers, Doris Milkert, Kitty L. Milliken, Julia K. Morgan, Pedro Ramirez, Karl E. Seifert, Timothy J. Shaw, Chris Wilson, Chuan Yin and Xixi Zhao. Proceedings of the Ocean Drilling Program, Scientific Results, Vol.149, p.705-712. Publisher: Texas A&M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 0884-5891
Note: In English. 37 refs.
Summary: A Pliocene-Pleistocene turbidite sequence sampled at four drill sites in a 75-km-long transect on the landward edge of the Iberia Abyssal Plain illustrates the effects of non-steady-state sedimentation on postdepositional geochemical processes. Organic carbon concentrations average 0.7% in sediments of this sequence at Sites 897 and 898 and 0.4% at Sites 899 and 900. Headspace concentrations of interstitial methane exceed 100,000 ppm in sediments from Sites 897 and 898 but are essentially zero in those from Sites 899 and 900. Methane concentrations do not rise until interstitial sulfate concentrations are virtually depleted, suggesting the presence of in situ methanogenic bacterial activity to sub-bottom depths of 300 m at Site 897 and 170 m at Site 898 and its absence at Sites 899 and 900. The turbidity flows that created the turbidite sequence on the Iberia Abyssal Plain evidently influenced postdepositional diagenesis at these sites. The principal factor is that the thicker turbidite sequences at Sites 897 and 898 protected organic matter from oxic, early degradation and thereby permitted anoxic, later degradation to proceed. In contrast, organic matter in the thinner turbidite sequences at Sites 899 and 900 was oxidized soon after deposition and was therefore not suitable for later microbial utilization. The difference in organic matter preservation between the sites has impacted microbial sulfate reduction and methane production in the turbidite sequences.
Year of Publication: 1996
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Aliphatic hydrocarbons; Alkanes; Anaerobic environment; Atlantic Ocean; C-13/C-12; Carbon; Cenozoic; Chemical composition; Concentration; Europe; Hydrocarbons; Iberian Peninsula; Iberian abyssal plain; Isotope ratios; Isotopes; Leg 149; Methane; Neogene; North Atlantic; Northeast Atlantic; O-18/O-16; ODP Site 897; ODP Site 898; ODP Site 899; ODP Site 900; Ocean Drilling Program; Organic compounds; Oxygen; Paleoenvironment; Pleistocene; Pliocene; Quaternary; Southern Europe; Stable isotopes; Sulfates; Tertiary; Turbidite
Coordinates: N404059 N404059 W0113616 W0113616
N404622 N404622 W0121604 W0121604
N404106 N404106 W0120725 W0120725
Record ID: 2007088127
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