Bottom Currents and Abyssal Sedimentation Processes South of Iceland.
An investigation was carried out to observe the geologic effects of steady bottom currents on sediments of East Katla Ridge on the southern insular rise of Iceland. Near-bottom southwest to west-flowing currents exceeded 20 cm/sec for two weeks over a 25-kilometer wide section of the ridge flank bet...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
1980
|
| Subjects: | |
| Online Access: | http://www.dtic.mil/docs/citations/ADA086952 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA086952 |
| Summary: | An investigation was carried out to observe the geologic effects of steady bottom currents on sediments of East Katla Ridge on the southern insular rise of Iceland. Near-bottom southwest to west-flowing currents exceeded 20 cm/sec for two weeks over a 25-kilometer wide section of the ridge flank between approximately 1400 and 1800 meters water depth; maximum density and minimum temperature were observed at 1800 meters. Total transport of Iceland-Scotland Overflow Water was calculated to be 5.0 x 10 to the sixth power cu m/sec. Suspended sediment transport is approximately 0.4 x 10 to the sixth power grams/sec, with a net deposition of 10 to 15 cm/1000 years estimated from the flux difference in and out of the station array. Sediment distribution patterns indicate that the current axis, where flow exceeds approximately 15 cm/sec, is a site of erosion and winnowing (sand layer formation) while the current margin is a site of rapid accumulation (from observed Holocene rates of 25 to 35 cm per 1000 yr to estimated rates of greater than 100 cm/1000 yr based on 3.5 kHz echosounder records). Holocene silty turbidites are locally thick in a submarine channel; sandy turbidites and current-winnowed 'sandy contourites' are present in the axis of the major submarine canyon. |
|---|