Texas A&M University
Department of Oceanography

Winter 1998 / Spring 1999 - Vol. 6, No. 3

Newly discovered seafloor channels formed by super-salty, flowing water

Discovery

The channels may not be very recent events.

 

 

 

 

 The brine-flow channels occur on the lower continental slope in water depths between 2,400 to 2,500 meters.

To obtain images of the seafloor, the oceanographers used sonar imaging instruments: a deep-towed, high-resolution (3.5 kHz) subbottom profiler and a 100 kHz side-scan sonar unit (see "Measuring the Depths"). Side-scan sonograms taken on the slopes of Vaca Basin illustrate the nature of newly discovered brine-flow channels.

Brine-flow channels observed on the flanks of Vaca Basin are well-developed and extend for great distances along the basin wall. The channels may not be very recent events, because we did not find high-salinity waters in the bottom of the basin. Also, brine flow into Vaca Basin may be periodic, since some of the channels intersect each other, thus indicating flow from different directions or at different times.

Similar brine-flow features, but not as extensive as those observed in Vaca Basin, occur on the flanks of submarine highs such as Green Knoll, a salt dome that is elevated 500 meters above the seafloor and is located seaward of the termination of the slope.

Harry Roberts of Louisiana State University has said that from a submersible, he has seen salt exposed at the seafloor on the top of Green Knoll.

Until now the origin of the channels observed on Green Knoll were unknown, but now we know they are brine-flow channels similar to those found in Vaca Basin.

Scientists examine the Department of Oceanography's sonar imaging instrument, called a towfish. Read "Measuring the Depths" for details about sonar imaging.

 

http://oceanography.tamu.edu/Quarterdeck/1998/3/bryant-3.html
Copyright 1998-1999, Department of Oceanography, Texas A&M University.
Updated November 24, 1998. (abdw)

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