Texas A&M University
Department of Oceanography
Newly discovered seafloor channels formed by super-salty, flowing water
The main ingredient:
Three slope canyons formed by moving salt
Salt was a key player in the formation of three
of four major canyon systems on the continental slope. Eroded into the complex
topography of the slope are the Mississippi Canyon, Keathley Canyon, Bryant
Canyon and Alaminos Canyon.
The Mississippi Canyon is a Pleistocene feature formed
about one million years ago by slope failure, seafloor "slumping"
processes, and debris and turbidity current flows.
The others - Alaminos Canyon, Keathley Canyon, and Bryant
Canyon - were created by the combination of coalescing salt canopies (uniting
of horizontal "pockets" of salt within the sediment layers), turbidity
currents, and debris flow erosional forces.
Draped over the late Pleistocene sediments of the slope
is a "blanket" of Holocene material. The Holocene blanket consists
of land-derived (terrigenous) sediment and deep-sea (pelagic) organisms,
and ranges in thickness from several meters to 10 meters thick.
During the Holocene high sea-stand, salt migrated upward
into portions of the eroded canyon areas at a rate of 3 to 6 centimeters
per year. In some areas of Bryant Canyon, salt rose as much as 600 meters.
-- William R. Bryant
http://oceanography.tamu.edu/Quarterdeck/1998/3/bryant-mainingredient.html
Copyright 1998-1999, Department
of Oceanography, Texas A&M University.
Updated November 24, 1998. (abdw)
Send Quarterdeck inquiries to quarterdeck@ocean.tamu.edu.
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