Bottom currents and abyssal sedimentation processes south of Iceland
Shor, Alexander N.
MetadataShow full item record
LocationEast Katla Ridge
KeywordMarine sediments; Sedimentation and deposition; Ocean currents; Submarine geology; Ocean circulation; Atlantis II (Ship : 1963-) Cruise AII94-1
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-1 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 106 m3 sec-1; suspended sediment transport is approximately 0.4 x 106 grams sec-1, 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-1, 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 echo-sounder records). Holocene silty turbidites are locally thick in a sub-marine channel; sandy turbidites and current-winnowed 'sandy contourites' are present in the axis of the major submarine canyon. ‘ Sandy contourite' deposits beneath the axis of the Iceland-Scotland Overflow Current are very poorly sorted muddy sands lacking primary sedimentary structures. Bioturbation is inferred to cause the unique characteristics of these deposits, as well as the absence of fine silt laminae in 'muddy contourites' at the current margin.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Woods Hole Oceanographic Institution and the Massachusetts Institute of Technology October 1979
Suggested CitationThesis: Shor, Alexander N., "Bottom currents and abyssal sedimentation processes south of Iceland", 1979-10, DOI:10.1575/1912/1721, https://hdl.handle.net/1912/1721
Showing items related by title, author, creator and subject.
Implementation of the vortex force formalism in the coupled ocean-atmosphere-wave-sediment transport (COAWST) modeling system for inner shelf and surf zone applications Kumar, Nirnimesh; Voulgaris, George; Warner, John C.; Olabarrieta, Maitane (2012-01)The coupled ocean-atmosphere-wave-sediment transport modeling system (COAWST) enables simulations that integrate oceanic, atmospheric, wave and morphological processes in the coastal ocean. Within the modeling system, the ...
Investigation of the effect of a circular patch of vegetation on turbulence generation and sediment deposition using four case studies Ortiz, Alejandra C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2012-06)This study describes the spatial distribution of sediment deposition in the wake of a circular patch of model vegetation and the effect of the patch on turbulence and mean flow. Two difference types pf vegetation were ...
Von Arx, William S. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1950-03)During the past four years a deliberate effort has been made at the Woods Hole Oceanographic Institution to devise methods of kinematic observation generally suited to the needs of oceanographers. One result of this work, ...