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Seafloor Mapping Group
A 21-day field operation was conducted during August and September, 1998 in the estuaries and on the inner continental shelf off the northern Oregon and southern Washington coast to generate reconnaissance maps of the seafloor geology and the shallow subsurface stratigraphy. Sidescan sonar data were collected on the innermost shelf to document changes to the sea floor since 1997. Sediment samples, bottom photographs, and video images were collected to document the sea floor geology. Seismic-reflection profiles were collected to fill in gaps in the 1997 shelf-mapping program and to extend the framework geology from the shelf into the estuaries. The Columbia River has provided huge amounts of sediment to this shelf during the Holocene transgression. Previous studies have mapped the distribution and thickness of this modern deposit on the middle and outer shelf (Nittrouer and Sternberg, 1981; Wolf and others, 1997), however, its distribution on the inner shelf and its link to the adjacent estuarine systems were not as clearly understood because of incomplete data coverage in these areas. Anthropogenic activity within the Columbia River drainage basin (agriculture, logging, construction of dams, and dredging of the estuary mouth) may have altered the sediment discharge from the river which, in turn, may be affecting sediment distribution on the shelf and in adjacent coastal environments. The seismic-reflection data in concert with the sidescan-sonar imagery and sediment samples will provide an overall synthesis of the seafloor environment including the Holocene stratal geometry, the distribution of different sediment types, the distribution of mobile bedforms, outcrops of Pleistocene and older strata, and the locations of faults. The goal of this project is to provide a regional synthesis of the offshore geology to support a wide variety of management decisions and to provide a basis for further process-oriented investigations. The project is conducted cooperatively with the Washington State Department of Ecology and several universities including Portland State University, University of Wisconsin Eau Clair, University College of the Fraser Valley, Grays Harbor College, University of South Florida, and Oregon State University. Entity_and_Attribute_Detail_Citation Nittrouer, C.A., and Sternberg, R.W., 1981, The formation of sedimentary strata in an allochthonous shelf environment: the Washington continental shelf: Marine Geology, V. 42, p. 201-232. Wolf, S.C., Hamer, M.R., and McCrory, P.A., 1997, Quaternary geologic investigations of the Continental Shelf offshore southern Washington and northern Oregon: U.S. Geological Survey Open-File Report 97-67.
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This Compact Disc-Read Only Memory (CD-ROM) publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.
| Data format: | Link to folders containing SEG-Y data. in format SEG-Y |
|---|---|
| Network links: |
http://cmgds.marine.usgs.gov/data/1998_014_FA_b/ http://cmgds.marine.usgs.gov/data/1998_014_FA_p/ http://cmgds.marine.usgs.gov/data/1998_014_FA_s/ |
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