Evidence for Sediment Eruption on Deep Sea Floor, Gulf of Mexico

Prior, David B.; Doyle, E.H.; Kaluza, Michael J.

doi:10.1126/science.243.4890.517

Cited by 86 publications

(37 citation statements)

References 8 publications

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“…One explanation for some of the major slumps on continental rises relates to instability of the sediments caused by the breakdown of gas hydrates (Summerhayes et al, 1979;Embley, 1980;Carpenter, 1981;Cashman and Popenoe, 1985;Prior et al, 1989). Seismic data near some slump areas show numerous normal faults that sole-out at or near the BSR (Popenoe et al, 1993).…”

Section: Role In Continental Margin Sediment Instabilitymentioning

confidence: 99%

Gas Hydrate Sampling on the Blake Ridge and Carolina Rise

Paull¹,

Matsumoto²,

Wallace³

1995

ODP Scientific Prospectus

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Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, the participating agencies, Joint Oceanographic Institutions, Inc., Texas A&M University, or Texas A&M Research Foundation. This Scientific Prospectus is based on pre-cruise JOIDES panel discussions. The operational plans within reflect JOIDES Planning Committee and thematic panel priorities. During the course of the cruise, actual site operations may indicate to the Co-Chief Scientists and the Operations Superintendent that it would be scientifically or operationally advantageous to amend the plan detailed in this prospectus. It should be understood that any proposed changes to the plan presented here are contingent upon approval of the Director of the Ocean Drilling Program in consultation with the Planning Committee and the Pollution Prevention and Safety Panel. ABSTRACTODP Leg 164 will be devoted to refining our understanding of the in situ characteristics of natural gas hydrates. The program involves drilling four sites to 750-m depths on the Blake Ridge that extend down through the zone where gas hydrates are stable and into the sedimentary section below. Short holes (50 m) will also be drilled at three sites on the crests of two diapirs on the Carolina Rise where gas hydrate-bearing sedimentary sections have been disturbed by the intrusion of diapirs. Because of the ephemeral nature of the gas hydrates, emphasis will be placed on downhole measurements and sampling strategies that allow the in situ conditions of the gas hydrates to be reconstructed.The objectives of Leg 164 include 1) assessing the amounts of gas trapped in extensively hydrated sediments, 2) contributing to an understanding of the lateral variability in the extent of gas hydrate development, 3) refining the understanding of the relationship between bottomsimulating reflectors and gas hydrate development, 4) investigating the distribution and in situ fabric of gas hydrates within sediments, 5) establishing the changes in the physical properties (porosity, permeability, velocity, thermal conductivity, etc.) associated with gas hydrate formation and decomposition in continental margin sediments, 6) determining whether the gas captured in gas hydrates is produced locally or has migrated from elsewhere, 7) investigating the role of gas hydrates in the formation of authigenic carbonate nodules, 8) refining our understanding of chemical and isotopic composition of gas hydrates, 9) determining the gas composition, hydration number, and crystal structure of natural gas hydrates, 10) determining the role of gas hydrates in stimulating or modifying fluid circulation, 11) investigating the potential connection between major slumps and the breakdown of gas hydrate, and 12) establishing the influence of the Carolina Rise diapirs on the gas hydrates as well as the origin of the diapirs themselves.

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Section: Role In Continental Margin Sediment Instabilitymentioning

confidence: 99%

Gas Hydrate Sampling on the Blake Ridge and Carolina Rise

Paull¹,

Matsumoto²,

Wallace³

1995

ODP Scientific Prospectus

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“…Prior et al, 1989;Solheim and Elverhøi, 1993;Long et al, 1998;Fichler et al, 2005;Davy et al, 2010). In the North Sea, buried Quaternary mega-pockmarks are much more abundant than in the Barents Sea, but likewise, they are located in the vicinity of hydrocarbon discoveries, shallow gas accumulations and regional faults (Fichler et al, 2005).…”

Section: Uru Depressions: Glaciotectonics Vs Gas Escapementioning

confidence: 99%

Hydrocarbon plumbing systems above the Snøhvit gas field: Structural control and implications for thermogenic methane leakage in the Hammerfest Basin, SW Barents Sea

Ostanin

Anka

Primio

et al. 2013

Marine and Petroleum Geology

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“…Sizes generally range from 10 to 200 m with 46 depths up to 35 m, but also giant pockmarks with diameters of up to 1 km or more 47 have been reported (Cole et al, 2000;Ondréas et al, 2005). Pockmarks can appear 48 as single features (Prior et al, 1989) or in aggregations of hundreds of pockmarks, 49 extending over tens of square kilometers (Lammers et al, 1995). 50 Hovland and Judd (1988) proposed a general model for pockmark evolution.…”

Section: But Many Published Examples Indicate Formation 38mentioning

confidence: 99%

Characterization of microbial activity in pockmark fields of the SW-Barents Sea

et al. 2012

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15 16Multibeam bathymetry revealed the occurrence of numerous craterlike depressions, 17 so-called pockmarks, on the sea floor of the Hammerfest Basin and the Loppa High, 18 south-western Barents Sea. To investigate whether these pockmarks are related to 19 ongoing gas seepage, microbial processes associated with methane metabolism 20 were analyzed using geochemical, biogeochemical and microbiological techniques. 21Gravity cores were collected along transects crossing individual pockmarks, allowing 22 a direct comparison between different locations inside (assumed activity center), on 23 the rim, and outside of a pockmark (reference sites). Concentrations of hydrocarbons 24 in the sediment, particularly methane, were measured as headspace (free) gas, and 25 in the occluded and adsorbed gas fraction. Down to a depth of 2.6 m below sea floor 26 2 (mbsf) sulfate reduction rates were quantified by radiotracer incubations. 27Concentrations of dissolved sulfate in the porewater were determined as well. Neither 28 the sulfate profiles nor the gas measurements show any evidence of microbial activity 29 or active fluid venting. Methane concentrations and sulfate reduction rates were 30 extremely low or even below the detection limit. The results show that the observed 31 sediment structures are most likely paleo-pockmarks, their formation probably 32 occurred during the last deglaciation. 33 34 Introduction 35Pockmarks are craterlike depressions in the seabed that form due to expulsion of 36

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Evidence for Sediment Eruption on Deep Sea Floor, Gulf of Mexico

Cited by 86 publications

References 8 publications

Gas Hydrate Sampling on the Blake Ridge and Carolina Rise

Gas Hydrate Sampling on the Blake Ridge and Carolina Rise

Hydrocarbon plumbing systems above the Snøhvit gas field: Structural control and implications for thermogenic methane leakage in the Hammerfest Basin, SW Barents Sea

Characterization of microbial activity in pockmark fields of the SW-Barents Sea

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