| Title | CMECS map for an area of the Oregon Outer Continental Shelf relevant to renewable energy |
| Download | Download (whole publication) |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Cochrane, G R; Hemery, L G; Henkel, S K; Schroeder, D M |
| Source | Program and abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada; by Todd, B J ; Brown, C J; Lacharité, M; Gazzola, V; McCormack, E; Geological Survey of Canada, Open File 8295, 2017 p. 43, https://doi.org/10.4095/305840  Open Access |
| Links | GeoHab 2017
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| Year | 2017 |
| Publisher | Natural Resources Canada |
| Meeting | 2017 GeoHab: Marine Geological and Biological Habitat Mapping; Dartmouth, NS; CA; May 1-4, 2017 |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Program and abstracts: 2017
GeoHab Conference, Dartmouth, Nova Scotia, Canada |
| File format | pdf |
| Area | Oregon; United States of America |
| Lat/Long WENS | -131.0000 -123.5000 46.5000 42.0000 |
| Subjects | marine geology; stratigraphy; surficial geology/geomorphology; engineering geology; History and Archaeology; environmental geology; Health and Safety; mapping techniques; oceanography; marine
environments; coastal studies; conservation; marine organisms; marine ecology; resource management; ecosystems; energy resources; continental margins; continental shelf; seafloor topography; bathymetry; hydrologic properties; geophysical surveys;
acoustic surveys, marine; sonar surveys; seismic surveys, marine; seismic reflection surveys; photography; marine sediments; benthos; slumps; slump structures; pockmarks; biotopes; biomes; Oregon Outer Continental Shelf; Biology; Renewable energy;
Wind energy |
| Program | Offshore Geoscience |
| Released | 2017 09 26 |
| Abstract | In 2014 the USGS and the BOEM entered into an Intra-agency agreement to map an area of the Oregon Outer Continental Shelf (OCS) off of Coos Bay, Oregon under consideration for development of a floating
wind energy farm. The BOEM requires seafloor mapping and site characterization studies in order to evaluate the impact of seafloor and sub-seafloor conditions on the installation, operation, and structural integrity of proposed renewable energy
projects, as well as to assess the potential effects of construction and operations on archaeological resources. The mission of the USGS is to provide geologic, topographic, and hydrologic information that contributes to the wise management of the
Nation's natural resources and that promotes the health, safety, and well-being of the people.
For the Oregon OCS study the USGS acquired multibeam echo sounder (MBES) and seafloor video data surrounding the proposed development site, a 95 km2
area 15 miles offshore of Coos Bay, Oregon. The USGS subsequently produced a bathymetry digital elevation model and backscatter intensity grids. Analysis of the video data was conducted by OSU and a Coastal and Marine Ecosystems Classification
Standard (CMECS) geoform and substrate component interpretation of the MBES data was conducted by the USGS.
Though combinations of mud and sand dominate the surficial substrate there is a diverse assortment of geomorphologic features related to
geologic processes. Video supervised numerical analysis of the MBES backscatter intensity data and vector ruggedness derived from the MBES bathymetry data was used to produce a substrate model for the study area called a seafloor character raster.
The sea floor character raster consists of three substrate classes, soft-flat areas, hard-flat areas and hard-rugged areas that were used to generate CMECS substrate attributes. For substrate polygons that had video grain size information a finer
level of CMECS grain size was added to the map. CMECS geoform attributes were produced using depth, slope and benthic position index classes to delineate geoform boundaries. Seven geoforms were identified in this process including ridges, slump
scars, slump deposits, basins and pockmarks. There is one anticlinal ridge where bedrock is exposed, a slump and associated scarps, and pockmarks. Pockmarks are seen in the form of fields of small pockmarks (< 100 metres diameter), a lineation of
large pockmarks with methanogenic carbonates, and areas of large pockmarks that have merged into larger variously shaped depressions. The slump appears to have originated at the pockmark lineation. Existing multichannel seismic data was examined to
attempt to identify crustal faults associated with pockmark areas and lineations. Faults related to anticlines could be inferred by displacement of reflecting strata but structures related to pockmarks could not be resolved.
Statistical analysis
of the video data for correlations between substrate, depth and biotic assemblages by OSU resulted in the identification of seven biomes, three hard bottom biomes and 4 soft bottom biomes. A biotope map was generated using the seafloor character
raster and the substrate and depth values of the biomes. Hard substrate biotopes were small in size and were located primarily on the ridge and in pockmarks along the pockmark lineation. The soft bottom biotopes consisted of large contiguous areas
delimited by isobaths. |
| Summary | (Plain Language Summary, not published)
The sixteenth annual GeoHab Conference was held this year (2017) at the Waterfront Campus of the Nova Scotia Community College in Dartmouth, Nova Scotia,
Canada. |
| GEOSCAN ID | 305840 |
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