Gas Hydrate Exploration, Mid Chilean Coast; Geochemical-Geophysical Survey
Memorandum rept., Oct 2004
NAVAL RESEARCH LAB WASHINGTON DC CHEMISTRY DIV
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The Naval Research Laboratory NRL, supported through ONRG-Chile, DOENETL, and ONR, participated in a research cruise along the mid-Chilean coast. Specific research topics addressed by NRL in this program include survey and prediction of geotechnical and geoacoustical anomalies, estimation of coastal hydrate distribution, refining protocol for hydrate exploration, and understanding the variation in microbial community diversity in hydrate-rich regions. The Chile-FONDEF goal in this program is to locate hydrates along the Chilean coast in terms of distribution and methane content for understanding the available energy and geological hazards. This effort integrates future energy exploration with ocean and climate research topics. The examination of sediments in this region was conducted in a collaborative effort between NRL, Milbar Hydrotest, Inc., Virginia Institute of Marine Science, Pontificia Universidad Catolica de Valparaiso, University of Concepcion, and Rice University. Piston coring, heatflow and biological sample sites were selected in two regions on the basis of previous seismic surveys taken during April 2003 and work conducted by scientists at the University of Concepcion. The coring and heatflow, along the previous NRL seismic line DTAGS, was run between 3610.38S, 7335.72W and 3612.50S, 733976W. Sulfate, sulfide, methane, chloride, and dissolved inorganic carbon DIC probes from piston core porewater samples, heatflow data and seismic profiles were combined to survey the presence of hydrates in this region. Fourteen out of 15 piston cores in this region were successful. Heatflow data was collected at 21 sites through the transect. An additional sample region was selected at the base of a 40 meter sub-sea mound located at 3622S, 7343W where biologists from University of Concepcion located large concentrations of benthic organisms.
- Physical and Dynamic Oceanography
- Geology, Geochemistry and Mineralogy