Partitioning of sediment on the shelf offshore of the Columbia River littoral cell Twichell, David C. Cross, VeeAnn A. Peterson, Curt D. 2010-07-07T17:44:43Z 2010-07-07T17:44:43Z 2010-02-11
dc.description This paper is not subject to U.S. copyright. The definitive version was published in Marine Geology 273 (2010): 11-31, doi:10.1016/j.margeo.2010.02.001. en_US
dc.description.abstract Sediment derived from the Columbia River has been deposited on the continental shelf, along the barriers and beaches, and in the bays of the Oregon and Washington coast during the Holocene. The barrier and beach deposits of this 150-km section of coast comprise approximately 6 km3 of these Holocene sediments (Peterson et al., 2010-this issue) while the fluvial and bay deposits comprise about 104 km3 (Baker et al., 2010-this issue), and the shelf deposit is approximately 79 km3. Seismic-reflection, sidescan sonar, and surface sediment data show that the shelf deposit is not uniform in distribution or composition. The shelf deposit is 15–50 m thick off the beaches of the southern part of the study area but is less than 3 m thick, and, in places, absent from the inner shelf in the northern third of the study area. Surface sediment texture of the shelf deposit varies as well. Pleistocene-age gravel covers parts of the inner shelf in the northern third of the area. To the south, the surface of the Holocene shelf deposit is composed of fine sand near shore that grades offshore to dominantly very fine sand in 25–30 m water depth and muddy sand on the middle and outer shelf (> 50 m depth). Although a huge volume of sediment covers the shelf, its uneven distribution indicates that in places only small amounts are available as a potential offshore source to the adjacent beaches, and in other places the finer-grained nature of the shelf deposit indicates that significant winnowing of fine sediment would be necessary to make it compositionally equivalent to sediment on adjacent beaches. en_US
dc.format.mimetype application/pdf
dc.identifier.citation Marine Geology 273 (2010): 11-31 en_US
dc.identifier.doi 10.1016/j.margeo.2010.02.001
dc.language.iso en_US en_US
dc.publisher Elsevier B.V. en_US
dc.subject Continental shelf en_US
dc.subject Holocene sediments en_US
dc.subject Columbia River en_US
dc.title Partitioning of sediment on the shelf offshore of the Columbia River littoral cell en_US
dc.type Article en_US
dspace.entity.type Publication
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relation.isAuthorOfPublication.latestForDiscovery d0c18f4f-3c4b-4313-ad14-f210b23fe637
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