Lithium, boron, and their isotopes in sediments and pore waters of Ocean Drilling Program Site 808, Nankai Trough; implications for fluid expulsion in accretionary prisms

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doi: 10.1130/0091-7613(1995)023<0037:LBATII>2.3.CO;2
Author(s): You, C. F.; Chan, L. H.; Spivack, A. J.; Gieskes, J. M.
Author Affiliation(s): Primary:
Scripps Institution of Oceanography, La Jolla, CA, United States
Other:
Louisiana State University, Department of Geology and Geophysics, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 23(1), p.37-40. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 23 refs.; illus.
Summary: Results from a comprehensive study of B, δ11B, Li, andδ6Li distributions in both sediment and pore-water samples of Ocean Drilling Program Site 808, Nankai Trough, Japan, show a strong correlation between Li and B concentrations, in agreement with previously published information from surface-marine sediments, suggesting similar geochemical behavior in sedimentary environments. The δ6Li and δ11B analyses provide additional data on the systematics of Li and B in marine sediments. Our results provide information on fluid-expulsion activity that has occurred at this drill site. Anomalies in all these constituents in the vicinity of the decollement zone (∼960 m below sea floor [mbsf]) suggest an influx of deeply generated fluids having distinct chemical compositions. The maximum concentrations of B and Li in bulk sediment, as well as their corresponding isotopic compositions, suggest uptake of both elements via chemisorption or secondary-mineral formation near the fluid conduit associated with the decollement zone. The low δ11B in pore waters suggests contribution of exchangeable plus lattice-bound B from greater depths. The corresponding high δ6Li similarly indicates mobilization from sediment under high-temperature conditions.
Year of Publication: 1995
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 07 Marine Geology and Oceanography; 18 Geophysics, Solid-Earth; Accretionary wedges; Alkali metals; B-11/B-10; Boron; Dehydration; Fluid expulsion; Fluid phase; Geochemistry; Isotopes; Leg 131; Leg 132; Li-6; Lithium; Marine sediments; Metals; Migration of elements; Mobilization; Nankai Trough; North Pacific; Northwest Pacific; ODP Site 808; Ocean Drilling Program; Pacific Ocean; Pore water; Sediments; Stable isotopes; Subduction zones; West Pacific
Coordinates: N322105 N322111 E1345646 E1345634
Record ID: 1995026965
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