Walsh, Frederick Bond (2006): The Kopanoar mud volcano on the Mackenzie Shelf, Beaufort Sea; implications for methane release on Arctic shelves

Leg/Site/Hole:
ODP 130
DSDP 8
DSDP 94
DSDP 94 609
ODP 130 805
Identifier:
2012-015352
georefid

Creator:
Walsh, Frederick Bond
author

Identification:
The Kopanoar mud volcano on the Mackenzie Shelf, Beaufort Sea; implications for methane release on Arctic shelves
2006
72 pp.
Fifty sites on the Mackenzie Shelf were sampled for foraminifera as part of the 2004 (Leg 8) Canadian Shelf Exchange Study (CASES). Part of this study sampled the Kopanoar mud volcano. A group of species observed on the Kopanoar mud volcano are described, along with the possibility of using the foraminifera to detect methane gas on the shelf and the implications (if any) this may have on the atmosphere. Two cores, 805A from the top of the mud volcano and 805C from the moat of the mud volcano, had samples taken every centimeter. Another core, 609A, from a non-mud volcano control site in the pingo area of the shelf, was sampled every 5 centimeters. The foraminifera in the core samples are typical for the Arctic shelf marine environment and include species such as Islandiella teretis and Elphidium exc. f. clavatum. The presence of Ammotium cassis in parts of the cores may be an indicator that thermogenic methane is being released from the mud volcano area, along with the possibility of oxidation of biogenic methane in the non mud volcano area. The presence of Trochammina macrescens implies ice transport from salt marshes on the Mackenzie Delta. Elphidiella hannai has been found for the first time north of Vancouver Island, and seems only to occur with methane related areas. The three cores contain 37 species. The >63 mu samples had the highest diversity of foraminifera and the >45 mu < 63 mu samples had large numbers but relatively few species; some of these species were deep water Arctic species. The species that were found in the small fraction were normally not found in the >63 mu size fraction. The 805A sample had foraminifera in the top three centimeters followed by a dead zone with no foraminifera until the 14 centimeter level. A second dead zone occurred in the lower half of the 805A core. These dead zones could be interpreted as a sign of higher than normal methane activity. No such zone was found in the 805C which is at the base of the mud volcano, although there is a good presence of Ammotium cassis. This suggests, that at least during two periods of time, that there were much higher concentrations of methane seepage at the summit of the volcano, than there were at the areas of the other two cores.
English
Thesis or Dissertation
Coverage:Geographic coordinates:
North:76.0000
West:-156.0000East: 160.3147
South:1.1340

Quaternary geology; aliphatic hydrocarbons; alkanes; Arctic Ocean; Atlantic Ocean; Beaufort Sea; biogeography; British Columbia; Canada; Cenozoic; cores; Deep Sea Drilling Project; DSDP Site 609; East Pacific; Equatorial Pacific; Foraminifera; geochemistry; glacial transport; hydrocarbons; Invertebrata; IPOD; Kopanoar mud volcano; Leg 130; Leg 8; Leg 94; Mackenzie Delta; methane; microfossils; Mid-Atlantic Ridge; mud volcanoes; North Atlantic; North Pacific; Northeast Atlantic; Northwest Pacific; Northwest Territories; Ocean Drilling Program; ODP Site 805; Ontong Java Plateau; organic compounds; Pacific Ocean; paleoecology; Protista; Quaternary; sampling; transport; Vancouver Island; West Pacific; Western Canada;

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