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  • 140; 157-1; 169; Bush Hill; Campeche Knoll; Center for Marine Environmental Sciences; Chapopote; GC; GeoB10618; Gravity corer; M67/2b; MARUM; Meteor (1986); OTEGA II; SO174/1; SO174/1_47-1; SO174/1_96; SO174/2; SO174/2_140; SO174/2_157-1; SO174/2_169; Sonne; Television-Grab; TVG  (1)
  • 204-1244C; 204-1245B; 204-1247B; 204-1248C; 204-1249C; 204-1249F; 204-1250C; 204-1250D; DRILL; Drilling/drill rig; Joides Resolution; Leg204; North Pacific Ocean; Ocean Drilling Program; ODP  (1)
Document type
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Years
  • 1
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    Unknown
    Gas hydrate structures and C1-C5 hydrocarbons at individual sites in the Gulf of Mexico (2010)
    PANGAEA
    In:  Supplement to: Klapp, Stephan A; Bohrmann, Gerhard; Kuhs, Werner F; Murshed, Mangir M; Pape, Thomas; Klein, Helmut; Techmer, Kirsten S; Heeschen, Katja U; Abegg, Friedrich (2010): Microstructures of structure I and II gas hydrates from the Gulf of Mexico. Marine and Petroleum Geology, 27(1), 116-125, https://doi.org/10.1016/j.marpetgeo.2009.03.004
    Details
    Publication Date: 2023-03-03
    Description: Gas hydrate samples from various locations in the Gulf of Mexico (GOM) differ considerably in their microstructure. Distinct microstructure characteristics coincide with discrete crystallographic structures, gas compositions and calculated thermodynamic stabilities. The crystallographic structures were established by X-ray diffraction, using both conventional X-ray sources and high-energy synchrotron radiation. The microstructures were examined by cryo-stage Field-Emission Scanning Electron Microscopy (FE-SEM). Good sample preservation was warranted by the low ice fractions shown from quantitative phase analyses. Gas hydrate structure II samples from the Green Canyon in the northern GOM had methane concentrations of 70-80% and up to 30% of C2-C5 of measured hydrocarbons. Hydrocarbons in the crystallographic structure I hydrate from the Chapopote asphalt volcano in the southern GOM was comprised of more than 98% methane. Fairly different microstructures were identified for those different hydrates: Pores measuring 200-400 nm in diameter were present in structure I gas hydrate samples; no such pores but dense crystal surfaces instead were discovered in structure II gas hydrate. The stability of the hydrate samples is discussed regarding gas composition, crystallographic structure and microstructure. Electron microscopic observations showed evidence of gas hydrate and liquid oil co-occurrence on a micrometer scale. That demonstrates that oil has direct contact to gas hydrates when it diffuses through a hydrate matrix.
    Keywords: 140; 157-1; 169; Bush Hill; Campeche Knoll; Center for Marine Environmental Sciences; Chapopote; GC; GeoB10618; Gravity corer; M67/2b; MARUM; Meteor (1986); OTEGA II; SO174/1; SO174/1_47-1; SO174/1_96; SO174/2; SO174/2_140; SO174/2_157-1; SO174/2_169; Sonne; Television-Grab; TVG
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
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    Unknown
    Hydrate, ice and quartz content of eight holes of Leg 204 (2007)
    PANGAEA
    In:  Supplement to: Bohrmann, Gerhard; Kuhs, Werner F; Klapp, Stephan A; Techmer, Kirsten S; Klein, Helmut; Murshed, Mangir M; Abegg, Friedrich (2007): Appearance and preservation of natural gas hydrate from Hydrate Ridge sampled during ODP Leg 204 drilling. Marine Geology, 244(1-4), 1-14, https://doi.org/10.1016/j.margeo.2007.05.003
    Details
    Publication Date: 2024-01-09
    Description: The state of preservation of natural gas hydrate samples, recovered from 6 sites drilled during ODP Leg 204 at southern summit of Hydrate Ridge, Oregon Margin, has been investigated by X-ray diffraction (XRD) and cryo-scanning-electron-microscopy (cryo-SEM) techniques. A detailed characterization of the state of decomposition of gas hydrates is necessary since no pressurized autoclave tools were used for sampling and partial dissociation must have occurred during recovery prior to the quench and storage in liquid nitrogen. Samples from 16 distinct horizons have been investigated by synchrotron X-ray diffraction measurements at HASYLAB/ Hamburg. A full profile fitting analysis (“Rietveld method”) of synchrotron XRD data provides quantitative phase determinations of the major sample constituents such as gas hydrate structure I (sI), hexagonal ice (Ih) and quartz. The ice content (Ih) in each sample is related to frozen water composed of both original existing pore water and the water from decomposed hydrates. Hydrate contents as measured by diffraction vary between 0 and 68 wt.% in the samples we measured. Samples with low hydrate content usually show micro-structural features in cryo-SEM ascribed to extensive decomposition. Comparing the appearance of hydrates at different scales, the grade of preservation seems to be primarily correlated with the contiguous volume of the original existing hydrate; the dissociation front appears to be indicated by micrometer-sized pores in a dense ice matrix.
    Keywords: 204-1244C; 204-1245B; 204-1247B; 204-1248C; 204-1249C; 204-1249F; 204-1250C; 204-1250D; DRILL; Drilling/drill rig; Joides Resolution; Leg204; North Pacific Ocean; Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 8 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
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