No Evidence for Enhanced Methane Flux from the Blake Ridge Depression
Charles K. Paull, William Ussler, III, 2009. "No Evidence for Enhanced Methane Flux from the Blake Ridge Depression", Natural Gas Hydrates—Energy Resource Potential and Associated Geologic Hazards, T. Collett, A. Johnson, C. Knapp, R. Boswell
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Piston cores were collected from the floor, flanks, and background sediments associated with the Blake Ridge Depression (BRD) off the east coast of the United States to determine if this area is a gas-venting site. The hypothesis was that if the depression is associated with focused methane flux, authigenic carbonate mineralization, indicative of methane-related diagenesis and/or steeper pore-water sulfate gradients, should occur within the feature. Sulfate gradients are sensitive to elevated pore-water methane concentrations and anaerobic methane oxidation. Compared with surrounding background sediments, neither steep sul-fate gradients nor authigenic carbonates were observed within the cores collected from the interior of the BRD. The hypothesis that the Black Ridge Depression is or has been a site of enhanced methane venting is not supported by these geochemical observations.
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In September 2004, the American Association of Petroleum Geologists (AAPG) convened a Hedberg Research Conference in Vancouver, British Columbia, Canada titled "Natural Gas Hydrates: Energy Resource Potential and Associated Geologic Hazards." As a continuation of the Hedberg Research Conference in Vancouver, the conveners of the conference and the editors of this Memoir have worked with more than 150 authors and coauthors to prepare this Memoir on gas hydrates. This publication follows the goals of the Hedberg conference; however, the contents of this Memoir were expanded to include all aspects of gas hydrates in nature. This Memoir contains 39 individual contributions, ranging from long topical summaries to shorter focused research papers. This Memoir has been published in two parts, with digital versions of all the complete research papers included on the enclosed CD. The hardcopy portion of the Memoir includes abstracts and several key figures for each of the contributions along with a complete copy of a gas hydrate technical review. The digital portion of this Memoir has been organized into a series of topical sections consisting of review articles, marine gas hydrate papers, and gas hydrate laboratory and modeling studies. Because of the rapidly emerging worldwide interest in gas hydrates, this comprehensive treatise on the geology of gas hydrates will be valuable to both the gas hydrate research community and exploration/development geologists working in arctic and deep marine environments.