Authigenic molybdenum formation in marine sediments: A link to pore water sulfide in the Santa Barbara Basin

Publication Type  Journal Article
Year of Publication  2000
Authors  Zheng, Y.; Anderson, R. F.; van Geen, A.; Kuwabara, J.
Journal Title  Geochimica Et Cosmochimica Acta
Volume  64
Issue  24
Pages  4165-4178
Journal Date  Dec
ISBN Number  0016-7037
Accession Number  ISI:000165857100006
Key Words  saanich inlet sediments; black-sea; pacific-ocean; trace-metals; early diagenesis; varve formation; cariaco trench; california; uranium; geochemistry

Pore water and sediment Mo concentrations were measured in a suite of multicores collected at four sites along the northeastern flank of the Santa Barbara Basin to examine the connection between authigenic Mo formation and pore water sulfide concentration. Only at the deepest site (580 m), where pore water sulfide concentrations rise to >0.1 muM right below the sediment water interface, was there active authigenic Mo formation. At shallower sites (550, 430, and 340 m), where pore water sulfide concentrations were consistently <0.05 M, Mo precipitation was not occurring at the time of sampling. A sulfide concentration of similar to0.1 muM appears to be a threshold for the onset of Mo-Fe-S co-precipitation. A second threshold sulfide concentration of similar to 100 muM is required for Mo precipitation without Fe, possibly as Mo-S or as particle-bound Mo.


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URL  <Go to ISI>://000165857100006