Three-dimensional distribution of gas hydrate beneath southern Hydrate Ridge; constraints from ODP Leg 204

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doi: 10.1016/j.epsl.2004.03.035
Author(s): Tréhu, Anne M.; Long, P. E.; Torres, M. E.; Bohrmann, G.; Rack, F. R.; Collett, T. S.; Goldberg, D. S.; Milkov, A. V.; Riedel, M.; Schultheiss, P.; Bangs, N. L.; Barr, S. R.; Borowski, W. S.; Claypool, G. E.; Delwiche, M. E.; Dickens, G. R.; Gracia, E.; Guerin, G.; Holland, M.; Johnson, J. E.; Lee, Y. J.; Liu, C. S.; Su, X.; Teichert, B.; Tomaru, H.; Vanneste, M.; Watanabe, M.; Weinberger, J. L.
Author Affiliation(s): Primary:
Oregon State University, College of Oceanic and Atmospheric Science, Corvallis, OR, United States
Other:
Pacific Northwest National Laboratory, United States
University of Bremen, Federal Republic of Germany
Joint Oceanographic Institutions, United States
U. S. Geological Survey, United States
Lamont-Doherty Earth Observatory, United States
Woods Hole Oceanographic Institute, United States
Geological Survey of Canada, Canada
GEOTEK, United Kingdom
University of Texas at Austin, United States
University of Leicester, United Kingdom
Eastern Kentucky University, United States
Idaho National Engineering and Environmental Laboratory, United States
Rice University, United States
Centre Mediterrani d'Investigacions Marines i Ambientals, Spain
Arizona State University, United States
Korea Institute of Geoscience and Mineral Resources, South Korea
National Taiwan University, Taiwan
China University of Geosciences, China
Universitat Bremen, Federal Republic of Germany
University of Tokyo, Japan
University of Tromso, Norway
Geological Survey of Japan, Japan
Scripps Institution of Oceanography, United States
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, 222(3-4), p.845-862. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 42 refs.; illus., incl. 2 tables, sketch map
Summary: Large uncertainties about the energy resource potential and role in global climate change of gas hydrates result from uncertainty about how much hydrate is contained in marine sediments. During Leg 204 of the Ocean Drilling Program (ODP) to the accretionary complex of the Cascadia subduction zone, we sampled the gas hydrate stability zone (GHSZ) from the seafloor to its base in contrasting geological settings defined by a 3D seismic survey. By integrating results from different methods, including several new techniques developed for Leg 204, we overcome the problem of spatial under-sampling inherent in robust methods traditionally used for estimating the hydrate content of cores and obtain a high-resolution, quantitative estimate of the total amount and spatial variability of gas hydrate in this structural system. We conclude that high gas hydrate content (30-40% of pore space or 20-26% of total volume) is restricted to the upper tens of meters below the seafloor near the summit of the structure, where vigorous fluid venting occurs. Elsewhere, the average gas hydrate content of the sediments in the gas hydrate stability zone is generally <2% of the pore space, although this estimate may increase by a factor of 2 when patchy zones of locally higher gas hydrate content are included in the calculation. These patchy zones are structurally and stratigraphically controlled, contain up to 20% hydrate in the pore space when averaged over zones ∼10 m thick, and may occur in up to ∼20% of the region imaged by 3D seismic data. This heterogeneous gas hydrate distribution is an important constraint on models of gas hydrate formation in marine sediments and the response of the sediments to tectonic and environmental change. Abstract Copyright (2004) Elsevier, B.V.
Year of Publication: 2004
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 07 Marine Geology and Oceanography; Accreting plate boundary; Aliphatic hydrocarbons; Alkanes; Cascadia subduction zone; Chemical composition; Climate; Climate change; Continental margin; East Pacific; Fluid phase; Gas hydrates; Geochemistry; Geophysical methods; Geophysical profiles; Geophysical surveys; Global change; Hydrate Ridge; Hydrocarbons; Hydrochemistry; Hydrothermal vents; Infrared methods; Leg 204; Marine sediments; Methane; Mid-ocean ridges; Models; North Pacific; Northeast Pacific; Ocean Drilling Program; Ocean floors; Organic compounds; Pacific Ocean; Resistivity; Sampling; Sea water; Sediments; Seismic methods; Seismic profiles; Spatial distribution; Surveys; Three-dimensional models; Well-logging
Coordinates: N443400 N443500 W1250400 W1250900
Record ID: 2006023697
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands