Pockmark (geology)
Pockmarks are craters in the seabed caused by fluids (gas and liquids) erupting and streaming through the sediments.
Pockmarks were discovered off the coasts of Nova Scotia, Canada in the late 1960s by Lew King and Brian McLean of the Bedford Institute of Oceanography. Pockmarks are uncommon on the land surface, and are expected in the ocean.
They were discovered off Nova Scotia, using a new side scan sonar developed in the late 1960s by Kelvin Hughes.
The craters off Nova Scotia are up to 150 m (490 ft) in diameter and 10 m (33 ft) deep. Pockmarks have been found worldwide.[1][2] Discovery was aided by the use of high-resolution multibeam acoustic systems for bathymetric mapping. In these cases, pockmarks have been interpreted as the morphological expression of gas or oil leakage from active hydrocarbon system or a deep overpressured petroleum reservoir.
See also
Bibliography
- Joseph T. Kelley, Stephen M. Dickson, Daniel F. Belknap,Walter A.Barnhardt and Mark Henderson, Giant sea-bed pockmarks: Evidence for gas escape from Belfast Bay, Maine ; doi: 10.1130/0091-7613(1994)022<0059:GSBPEF>2.3.CO;2 Geology January, 1994 v. 22, no. 1, p. 59-62 (Abstract)
References
- ↑ Judd, Alan and Martin Hovland, 'Seabed Fluid Flow: The Impact on Geology, Biology and the Marine Environment, Cambridge University Press, 2007, ISBN 978-0-521-81950-3
- ↑ Hovland, Martin, Seabed Pockmarks and Seepages : Geological Ecological and Environmental Implication, Springer, 1988, ISBN 978-0-86010-948-8