Occurrence and fractionation of light hydrocarbons in the gas-hydrate bearing sediments of IODP Site U1517, Hikurangi Margin, New Zealand

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Author(s): Heeschen, Katja U.; Torres, Marta E.; Pecher, Ingo Andreas; Schlömer, Stefan; Owari, Satoko; Rose, Paula S.; Karina, Machado; Schicks, Judith Maria; Hu, Gaowei; Mountjoy, Joshu J.; Barnes, Philip; LeVay, Leah; Solomon, Evan A.; Saffer, Demian M.; Wallace, Laura; Petronotis, Katerina E.
International Ocean Discovery Program, Expedition 372 Scientists, College Station, TX
Author Affiliation(s): Primary:
German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
Oregon State University, United States
University of Auckland, New Zealand
Federal Institute for Geosciences and Natural Resources, Germany
Chiba University, Japan
Texas A&M University Corpus Christi, United States
Federal University of Paraná, Brazil
GeoForschungsZentrum Potsdam, Germany
Institute of Marine Geology, China
National Institute of Water and Atmospheric Research, New Zealand
University of Washington, United States
Pennsylvania State University, United States
University of Texas at Austin, United States
Volume Title: AGU 2018 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2018; American Geophysical Union 2018 fall meeting, Washington, DC, Dec. 10-14, 2018. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Investigating the gas hydrate and hydrocarbon distribution of the Tuaheni Landslide Complex (TLC) was one of the main targets of IODP expedition 372 on the Hikurangi Margin east of New Zealand's North Island. Site U1517 was drilled into the creeping part of the TLC to depths of 205 mbsf passing through the base of the slide mass at shallower depth and the BSR just above the base of the hole. Logging while drilling (LWD) and pore water data reveal the occurrence of gas hydrates at roughly 105 - 160 mbsf with high saturations in thin coarse-grained sediments. Infrared imaging was used to quickly sample and freeze gas hydrate-bearing core sections in liquid nitrogen. Macroscopically, no gas hydrates could be observed. Coarse layers of the preserved core sections are investigated in on-shore labs using microscopy to look for gas hydrates, gas chromatography to measure degassed core sections, and Raman Spectroscopy to measure gas hydrate compositions - if applicable. Further, a large number of slightly overpressurized voids could be sampled throughout the length of the sediment core before cutting the core liners. This allows for a very good characterization of the gas composition with depth. Gas and isotopic composition of light hydrocarbons above, within and below the gas hydrate-bearing sediments were determined. The gas composition shows a close relationship with the gas hydrate occurrence.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 07 Marine Geology and Oceanography; Chemical composition; Continental margin; Expedition 372; Gas hydrates; Hikurangi Margin; IODP Site U1517; International Ocean Discovery Program; Marine sediments; Pacific Ocean; Sediments; South Pacific; Southwest Pacific; West Pacific
Coordinates: S384947 S384947 E1782834 E1782834
Record ID: 2019061707
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