| dc.description |
Large barite (BaSO4) structures mark cold seeps in the southern San Clemente
Basin. Barium flux to San Clemente sediments is two to three times greater than fluxes
measured in surrounding California Borderland basins. Analyses of sediment trap
material, water column samples, sediments and pore water indicate that expected bariumbearing
mineral phases (e.g. detrital aluminosilicates, biogenic material and Fe/Mn
oxyhydroxides) cannot account for excess barium accumulating in the San Clemente
Basin. This excess represents 7-70 % by weight of total sedimentary barium. Cold seep
barite is accumulating in San Clemente sediments at an average rate of approximately 11
μmol m-2 day-1, a value that is comparable to the combined flux of detrital and biogenic
material to the basin floor. Cold seep barite is largely unaccounted for in sedimentary
barium inventories. The magnitude of cold seep barite flux to San Clemente Basin
sediments and the occurrence of cold seeps throughout the oceans necessitate
consideration of this phase in the development of barium geochemical budgets and the
variety of paleoproxies involving barium in marine sediments. |
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