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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2004
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| Online Access: | https://doi.org/10.1594/PANGAEA.722485 |
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| _version_ | 1867171760971972608 |
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| author | Tréhu, Anne M Long, Philip E Torres, Marta E Bohrmann, Gerhard Rack, Frank R Collett, Tim S Goldberg, D S Milkov, Alexei V Riedel, Michael Schultheiss, P Bangs, N L Barr, Samantha R Borowski, Walter S Claypool, George E Delwiche, Mark E Dickens, Gerald Roy Gràcia, Eulàlia Guerin, Gilles Holland, M Johnson, J E Lee, Young-Joo Liu, C-S Su, Xin Teichert, Barbara M A Tomaru, Hitoshi Vanneste, M Watanabe, Mahito Weinberger, J L |
| author_facet | Tréhu, Anne M Long, Philip E Torres, Marta E Bohrmann, Gerhard Rack, Frank R Collett, Tim S Goldberg, D S Milkov, Alexei V Riedel, Michael Schultheiss, P Bangs, N L Barr, Samantha R Borowski, Walter S Claypool, George E Delwiche, Mark E Dickens, Gerald Roy Gràcia, Eulàlia Guerin, Gilles Holland, M Johnson, J E Lee, Young-Joo Liu, C-S Su, Xin Teichert, Barbara M A Tomaru, Hitoshi Vanneste, M Watanabe, Mahito Weinberger, J L |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | 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. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_722485 |
| institution | PANGAEA |
| language | en |
| publishDate | 2004 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Spacing and amplitude of IR temperature anomalies and hydrate content of sediments from ODP Leg 304 sites (Table 1) Tréhu, Anne M Long, Philip E Torres, Marta E Bohrmann, Gerhard Rack, Frank R Collett, Tim S Goldberg, D S Milkov, Alexei V Riedel, Michael Schultheiss, P Bangs, N L Barr, Samantha R Borowski, Walter S Claypool, George E Delwiche, Mark E Dickens, Gerald Roy Gràcia, Eulàlia Guerin, Gilles Holland, M Johnson, J E Lee, Young-Joo Liu, C-S Su, Xin Teichert, Barbara M A Tomaru, Hitoshi Vanneste, M Watanabe, Mahito Weinberger, J L 204-1244B; 204-1244C; 204-1244E; 204-1245A; 204-1245B; 204-1245C; 204-1246A; 204-1246B; 204-1247A; 204-1247B; 204-1248A; 204-1248C; 204-1249A; 204-1249F; 204-1250A; 204-1250C; 204-1250D; 204-1251A; 204-1251B; 204-1251D; 204-1252A; Calculated; Comment; Comment 2 (continued); Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; DRILL; Drilling/drill rig; Elevation of event; Event label; Hydrate; Joides Resolution; Latitude of event; Leg204; Length, difference; Longitude of event; North Pacific Ocean; Number; Ocean Drilling Program; ODP; Recovery; Spacing; Temperature, difference 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. |
| title | Spacing and amplitude of IR temperature anomalies and hydrate content of sediments from ODP Leg 304 sites (Table 1) |
| topic | 204-1244B; 204-1244C; 204-1244E; 204-1245A; 204-1245B; 204-1245C; 204-1246A; 204-1246B; 204-1247A; 204-1247B; 204-1248A; 204-1248C; 204-1249A; 204-1249F; 204-1250A; 204-1250C; 204-1250D; 204-1251A; 204-1251B; 204-1251D; 204-1252A; Calculated; Comment; Comment 2 (continued); Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; DRILL; Drilling/drill rig; Elevation of event; Event label; Hydrate; Joides Resolution; Latitude of event; Leg204; Length, difference; Longitude of event; North Pacific Ocean; Number; Ocean Drilling Program; ODP; Recovery; Spacing; Temperature, difference |
| url | https://doi.org/10.1594/PANGAEA.722485 |