Campeche Knolls
Campeche Knolls
Campeche Salt Dome Province | |
---|---|
Oceanic basin | |
Coordinates: 20°22′00″N 93°47′00″W / 20.366667°N 93.783333°W | |
Location | |
Part of | Campeche Bank |
Offshore water bodies | |
Area | |
• Total | 22,653.6 square nautical miles (30,000.0 sq mi; 77,700 km2)[2] |
Dimensions | |
• Length | 260.7 nautical miles (300.0 mi; 482.8 km)[2] |
• Width | 86.9 nautical miles (100.0 mi; 160.9 km)[2] |
• Depth | 672.5 fathoms (4,035 ft; 1,229.9 m) ~ 1,725 fathoms (10,350 ft; 3,155 m)[3] |
The Campeche Knolls are
The Campeche Knolls are covered with a thick column of sediments above the salt unit, with sediment thickness reaching 3–6 mi (4.8–9.7 km) depending upon water depth and distance from the southern coast. The thick sediments provided prolific petroleum source rocks with the most productive one being of latest Jurassic and Cretaceous age.[5] Hydrocarbon generation makes Campeche Knolls a highly ranked and prolific petroleum region, with studies showing that salt activity supports leakage of gas and oil.[5]
The potential for gas hydrate accumulations in the Campeche Knolls was demonstrated as early as 1970, with the retrieval of gassy cores from Site 88 drilled during Leg 10 of the
During the R/V Sonne SO174 research cruise in 2004, remote sensing results guided researchers to the discovery of oil, gas, and asphalt seepage on the top of one knoll in the northern tip of the Campeche Knolls province.[5] This knoll was named Chapapote, the Aztec word for “tar,” and is located at 21° 54’ N by 93° 26’ W in approximately 1.8 mi (3, 000 m) water depth. Extensive surface deposits of solidified asphalt are present at Chapapote, with one subcircular-shaped flow measuring at least 49 ft (15 m) across.[4] A diverse biological community is also present on the Chapapote, with a range of organisms, including tubeworms, bacterial mats, and chemosynthetic mussels all calling the area home.[4] A sample grab conducted on the cruise recovered sediment with thin layers of gas hydrate. Molecular and isotopic compositions of the gas hydrate indicated that the gas was moderately mature and thermogenic in nature.[4]
In 2006, the METEOR Cruise No. 67 (MC67/2b) returned to Chapapote. Hydrates were recovered at one gravity coring station, with Core 10618-1 containing a large piece of pure, white gas hydrate embedded in asphalt. The recovery of this core was accompanied by a strong rising of gas bubbles to the sea surface. It is assumed that hydrate formed internally after deposition of the asphalt.[8] Of the three samples collected from upper first meter of the core, two were composed of Structure I hydrate. The third was a mixture of both Structure I and Structure II.[9] Hydrocarbons from the Chapapote are dominantly thermogenic in origin as evidenced by the stable carbon isotopes of hydrate forming hydrocarbons.[4]
Importance of Campeche Knolls as a gas hydrates study site
The Chapapote asphalt volcano is located in the Campeche Knolls.It was there that the deepest known recovery of surficial gas hydrate occurred at a water depth of 1.8 mi (3,000 m). The gas hydrate was embedded in an asphalt matrix. Analyses of the hydrate showed both Structure-I and Structure-II gas hydrate present in the recovered sample.[8] The only known recovery of gas hydrate in the southern Gulf of Mexico also occurred in the Campeche Knolls.[10]
See also
References
- ^ Bahía de Campeche in Geonames.org (cc-by)
- ^ ISSN 0002-7464.
- )
- ^ S2CID 46477324.
- ^ a b c d Ding, et al. 2010. Ding, F., V. Spiess, I. R. MacDonald, M. Bruning, N. Fekete, and G. Bohrman. "Shallow sediment deformation styles in north-western Campeche Knolls, Gulf of Mexico and their controls on the occurrence of hydrocarbon seepage." Marine and Petroleum Geology 27 (2010): 959-972.
- ^ DSDP Leg 10 Shipboard Science Party 1973. DSDP Leg 10 Shipboard Science Party. "Site 88 Initial Report." In DSDP Leg 10, 55-70. Washington, D. C.: U.S. Govt. Printing Office, 1973.
- ^ a b c Worzel and Bryant 1973. Worzel, J. L., and W. R. Bryant. "Regional aspects of deep sea drilling in the Gulf of Mexico, leg 10." In Initial Reports of the Deep Sea Drilling Project – Galveston, Texas to Miami, Florida, v. 10, 737-748. Washington, D.C.: U.S. Govt. Printing Office, 1973.
- ^ a b Bohrman and Spiess 2006. Bohrman, G., and V. Spiess. Fluid seepage in the Gulf of Mexico. Vol. 263, in Report and preliminary results of R/V METEOR Cruise M67/2a and 2b, Balboa-Tampico-Bridgetown, 15 March-24 April 2006, 119 pp. Bremen, Germany: University of Bremen, Dept. of Geosciences, 2006.
- ^ Klapp, et al. 2010. Klapp, S. A., et al. "Mixed gas hydrate structures at the Chapopote Knoll, southern Gulf of Mexico." Earth and Planetary Sciences Letters 299 (2010): 201-217.
- ^ Hutchinson 2011. Hutchinson, D. R., Ruppel, C. D., Roberts, H. H., Carney, R. S., and Smith, M.A. "Gas Hydrates in the Gulf of Mexico." In Gulf of Mexico Origin, Waters, and Biota: Volume 3, Geology, by N. A. Buster and C. W. Holmes, 247-275. College Station, Texas: Texas A&M University Press, 2011.
External links
- "Deep Sea Drilling Project Reports and Publications". DSDP Volume X. ISSN 1936-7392.
- Perkins, Sid (May 12, 2004). "Underwater Pavement: Asphalt deposits cover parts of Gulf of Mexico". Science News. Society for Science.
- Ruppel, Carolyn; Carney, Robert S. (December 17, 2017). "Active Asphalt Seep Discovered in the Northern Gulf of Mexico". NOAA Ocean Exploration. National Oceanic and Atmospheric Administration.