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The Toms Canyon structure [~20-22 km wide] is located on the New Jersey outer continental shelf beneath 80-100 m of water, and is buried by ~1 km of upper Eocene to Holocene sedimentary strata. The structure displays several characteristics typical of terrestrial impact craters (flat floor; upraised faulted rim: brecciated sedimentary fill), but several other characteristics are atypical (an unusually thin ejecta blanket; lack of an inner basin, peak ring, or central peak; bearing nearly completely filled with breccia). Seismostratigraphic and biostratigraphic analyses show that the structure formed during planktonic foraminiferal biochron P15 of the early to middle late Eocene. The fill unit is stratigraphically...
Categories: Publication; Types: Citation; Tags: Marine Geology
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High-frequency Quaternary glacioeustasy resulted in the incision of six moderate- to high-relief fluvial erosion surfaces beneath the Virginia inner shelf and coastal zone along the updip edges of the Atlantic continental margin. Fluvial valleys up to 5 km wide, with up to 37 m of relief and thalweg depths of up to 72 m below modern mean sea level, cut through underlying Pleistocene and Mio-Pliocene strata in response to drops in baselevel on the order of 100 m. Fluvially incised valleys were significantly modified during subsequent marine transgressions as fluvial drainage basins evolved into estuarine embayments (ancestral generations of the Chesapeake Bay). Complex incised-valley fill successions are bounded...
Categories: Publication; Types: Citation; Tags: Marine Geology
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Observed morphodynamic changes over multiple decades were coupled with storm-driven run-up characteristics at Fire Island, New York, to explore the influence of wave processes relative to the impacts of other coastal change drivers on the near-term evolution of the barrier island. Historical topography was generated from digital stereo-photogrammetry and compared with more recent lidar surveys to quantify near-term (decadal) morphodynamic changes to the beach and primary dune system between the years 1969, 1999, and 2009. Notably increased profile volumes were observed along the entirety of the island in 1999, and likely provide the eolian source for the steady dune crest progradation observed over the relatively...
Categories: Publication; Types: Citation; Tags: Marine Geology
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Over 150 million m3 of sand-sized sediment has disappeared from the central region of the San Francisco Bay Coastal System during the last half century. This enormous loss may reflect numerous anthropogenic influences, such as watershed damming, bay-fill development, aggregate mining, and dredging. The reduction in Bay sediment also appears to be linked to a reduction in sediment supply and recent widespread erosion of adjacent beaches, wetlands, and submarine environments. A unique, multi-faceted provenance study was performed to definitively establish the primary sources, sinks, and transport pathways of beach-sized sand in the region, thereby identifying the activities and processes that directly limit supply...
Categories: Publication; Types: Citation; Tags: Marine Geology
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The mineralogical compositions of 119 samples collected from throughout the San Francisco Bay coastal system, including bayfloor and seafloor, area beaches, cliff outcrops, and major drainages, were determined using X-ray diffraction (XRD). Comparison of the mineral concentrations and application of statistical cluster analysis of XRD spectra allowed for the determination of provenances and transport pathways. The use of XRD mineral identifications provides semi-quantitative compositions needed for comparisons of beach and offshore sands with potential cliff and river sources, but the innovative cluster analysis of XRD diffraction spectra provides a unique visualization of how groups of samples within the San Francisco...
Categories: Publication; Types: Citation; Tags: Marine Geology
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Combined EM-300 multibeam bathymetric data and satellite photography reveal the physiography of the continental margin between 35°50′ and 37°03′N and from the shoreline west of 122°40′ and 122°37′W, which includes Monterey Bay, in a previously unprecedented detail. Patterns in these images clearly reveal the processes that are actively influencing the current geomorphology of the Monterey Bay region, including the Monterey Bay National Marine Sanctuary (MBNMS). Our data indicates that seafloor physiography within the MBNMS results from plate margin tectonic deformation, including uplift and erosion along structural lineaments, and from fluid flow. Mass wasting is the dominant process active within the Ascension–Monterey...
Categories: Publication; Types: Citation; Tags: Marine Geology
First release: 2015 Revised: July 2017 (ver. 2.0) Approximately 95 square kilometers of area was mapped with multibeam sonar. The survey expanded the extent of mapping data collected by Solmar Hydro Inc. in 2013 under a contract with WindFloat Pacific. When added to the Solmar Hydro data the total area mapped is approximately 140 square kilometers, lying in Federal waters on the shelf offshore of Coos Bay of interest for renewable energy (OCS-P lease blocks 6523, 6524, 6573, 6574, 6623, 6624, 6673, and 6674). Water depths range from 300 to 500 meters and are within the effective depth range of the Reson 7111. The seabed in his area is composed of sand and mud, with rocky outcrops on tectonically uplifted features....
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This part of DS 781 presents data for the isopachs for the Point Conception to Hueneme Canyon, California, region. The vector data file is included in "Isopachs_PointConceptionToHuenemeCanyon.zip," which is accessible from https://doi.org/10.5066/F7891424. As part of the USGS's California State Waters Mapping Project, a 50-m grid of sediment thickness for the seafloor within the 3-nautical mile limit between Point Conception and Hueneme Canyon was generated from seismic-reflection data collected in 2014 (USGS activity 2014-632-FA) supplemented with outcrop and geologic structure (fault) information following the methodology of Wong (2012). This sediment thickness layer was merged with a previously published sediment...
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This part of DS 781 presents data for the transgressive contours for the Point Conception to Hueneme Canyon, California, region. The vector file is included in "TransgressiveContours_PointConceptionToHuenemeCanyon.zip," which is accessible from http://dx.doi.org/10.5066/F7891424. As part of the USGS's California State Waters Mapping Project, a 50-m grid of sediment thickness for the seafloor within the 3-nautical mile limit between Point Conception and Hueneme Canyon was generated from seismic-reflection data collected in 2014 (USGS activity 2014-632-FA) supplemented with outcrop and geologic structure (fault) information following the methodology of Wong (2012). Water depths determined from bathymetry data were...
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As sea level rises and hurricanes become more intense, barrier islands around the world become increasingly vulnerable to conversion from self-sustaining migrating landforms to submerging or subaqueous sand bodies. To explore the mechanism by which such state changes occur and to assess the factors leading to island disintegration, we develop a suite of numerical simulations for the Chandeleur Islands in Louisiana, U.S.A., which appear to be on the verge of this transition. Our results suggest that the Chandeleurs are likely poised to change state, leading to their demise, within decades depending on future storm history. Contributing factors include high rates of relative sea level rise, limited sediment supply,...
Categories: Publication; Types: Citation; Tags: Marine Geology
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High resolution bathymetric, sea-floor backscatter, and seismic-reflection data were collected offshore of southeastern Louisiana aboard the research vessel Point Sur on May 19-26, 2017, in an effort to characterize mudflow hazards on the Mississippi River Delta front. As the initial field program of a research cooperative between the U.S. Geological Survey, the Bureau of Ocean Energy Management, and other Federal and academic partners, the primary objective of this cruise was to assess the suitability of sea-floor mapping and shallow subsurface imaging tools in the challenging environmental conditions found across delta fronts (for example, variably distributed water column stratification and widespread biogenic...
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The Monterey submarine canyon, incised across the continental shelf in Monterey Bay, California, provides a record of the link between onshore tectonism, fluvial transport, and deep-marine deposition. High-resolution seismic-reflection imaging in Monterey Bay reveals an extensive paleocanyon unit buried below the seafloor of the continental shelf around Monterey and Soquel canyon heads. Paleocanyons shifted position through numerous phases of cut-and-fill in response to Salinas, Pajaro, and San Lorenzo river extensions and avulsions across the continental shelf during high-frequency Pleistocene sea-level and climatic variations. Five seismic facies within the Monterey paleocanyon unit and below the modern canyon...
Categories: Publication; Types: Citation; Tags: Marine Geology
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The influences of wave climate and sediment supply on the depths of sand-mud transitions (hSMT) are investigated. Depths of sand-mud transitions (SMT) are based on published granulometric data from surface samples gathered from 14 sites in different wave-dominated coastal environments with fluvial input, including high energy (Columbia, Eel, Russian, San Lorenzo, Copper, and Nepean rivers), moderate energy (Ebro, Nile, Santa Clara, Tseng-wen and Kao-ping rivers), and low energy (Po, Pescara and Tronto rivers) regimes. Geometric mean diameter (GMD) and mud percent are compiled from samples along shore-normal transects, and significant correlation is found between these two textural descriptors. Nominally, the SMT...
Categories: Publication; Types: Citation; Tags: Marine Geology
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Geophysical and geological survey data were collected off Town Neck Beach in Sandwich, Massachusetts, in May and July 2016. Approximately 130 linear kilometers of subbottom (seismic-reflection) and 234-kilohertz interferometric sonar (bathymetric and backscatter) data were collected along with sediment samples, sea floor photographs, and (or) video at 26 sites within the geophysical survey area. Sediment grab samples were collected at 19 of the 26 sampling sites and video and (or) photographic imagery of the sea floor were taken at all 26 sites. These survey data are used to characterize the sea floor by identifying sediment-texture, seabed morphology, and underlying geologic structure and stratigraphy. Data collected...
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This part of DS 781 presents data for the isopachs of the Point Sur to Point Arguello, California, region. The vector data file is included in the “Isopachs_PointSurToPointArguello.zip,” which is accessible from https://doi.org/10.5066/P97CZ0T7. As part of the USGS's California State Waters Mapping Project, a 50-m grid of sediment thickness for the seafloor within the 3-nautical mile limit between Point Sur and Point Arguello was generated from seismic-reflection data collected between 2008 and 2014, and supplemented with geologic structure (fault and fold) information following the methodology of Wong (2012). Reference Cited: Wong, F. L., Phillips, E.L., Johnson, S.Y., and Sliter, R.W., 2012, Modeling of depth...
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This data release of dune metrics for the Massachusetts coast is part of a 2018 update to the Massachusetts Shoreline Change Project. Because of continued coastal population growth and the increased threat of coastal erosion, the Massachusetts Office of Coastal Zone Management (CZM) launched the Shoreline Change Project in 1989 to identify erosion-prone areas of the coast. Maps of historic shoreline locations from the mid-1800s to 1978 were produced from multiple data sources, and in 2001, a 1994 shoreline was added to enable the calculation of long- and short-term shoreline change rates. In 2013, the U.S. Geological Survey (USGS), in cooperation with CZM, delineated an additional oceanfront shoreline using 2007...
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Understanding how effectively methane can be extracted from a gas hydrate reservoir requires knowing how compressible, permeable, and strong the overlying seal sediment is. This data release provides results for flow-through permeability, consolidation, and direct shear measurements made on fine-grained seal sediment from Site NGHP-02-08 offshore eastern India. The sediment was collected in a pressure core from the Krishna-Godavari Basin during the 2015 Indian National Gas Hydrate Program Expedition 2 (NGHP-02). Gas hydrate is a crystalline solid that forms naturally in the sediment of certain marine and permafrost environments where pressure is relatively high (equivalent to the pressure measured ~300 meters water...
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Unvegetated to vegetated marsh ratio (UVVR) in the Fire Island National Seashore and Central Great South Bay salt marsh complex, is computed based on conceptual marsh units defined by Defne and Ganju (2018). UVVR was calculated based on U.S. Department of Agriculture National Agriculture Imagery Program (NAIP) 1-meter resolution imagery. Through scientific efforts initiated with the Hurricane Sandy Science Plan, the U.S. Geological Survey has been expanding national assessment of coastal change hazards and forecast products to coastal wetlands, including the Fire Island National Seashore and Central Great South Bay salt marshes, with the intent of providing Federal, State, and local managers with tools to estimate...
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The Sandy Hook artificial reef, located on the sea floor offshore of Sandy Hook, New Jersey was built to create habitat for marine life. The reef was created by the placement of heavy materials on the sea floor; ninety-five percent of the material in the Sandy Hook reef is rock. In 2000, the U.S. Geological Survey surveyed the area using a Simrad EM1000 multibeam echosounder mounted on the Canadian Coast Guard (CCG) ship Frederick G. Creed. The purpose of this multibeam survey, done in cooperation with the U.S. Army Corps of Engineers when the Creed was in the New York region in April 2000, was to map the bathymetry and backscatter intensity of the sea floor in the area of the Sandy Hook artificial reef. The collected...
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This data set collects, from peer-reviewed research, values of sea surface temperature (SST) that occurred at various sites across the Earth during a brief period of the mid-Piacenzian


map background search result map search result map Improving understanding of near-term barrier island evolution through multi-decadal assessment of morphologic change Integration of bed characteristics, geochemical tracers, current measurements, and numerical modeling for assessing the provenance of beach sand in the San Francisco Bay Coastal System Sand sources and transport pathways for the San Francisco Bay coastal system, based on X-ray diffraction mineralogy Isopachs--Point Conception to Hueneme Canyon, California Transgressive Contours--Point Conception to Hueneme Canyon, California Seismic Reflection, Geometrics multi-channel streamer tracklines, USGS field activity 2017-003-FA, Mississippi River Delta front offshore of southeastern Louisiana (Esri polyline shapefile, GCS WGS 84) Unvegetated to vegetated marsh ratio in Fire Island National Seashore and Central Great South Bay salt marsh complex, New York Dune Metrics for the Massachusetts Coast as Derived From 2013–14 Topographic Lidar Data Isopachs—Point Sur to Point Arguello, California Backscatter imagery collected in 2016 by the U.S. Geological Survey off Town Neck Beach Sandwich, Massachusetts during field activity 2016-017-FA (GeoTIFF image) Backscatter imagery collected in 2016 by the U.S. Geological Survey off Town Neck Beach Sandwich, Massachusetts during field activity 2016-017-FA (GeoTIFF image) Unvegetated to vegetated marsh ratio in Fire Island National Seashore and Central Great South Bay salt marsh complex, New York Improving understanding of near-term barrier island evolution through multi-decadal assessment of morphologic change Seismic Reflection, Geometrics multi-channel streamer tracklines, USGS field activity 2017-003-FA, Mississippi River Delta front offshore of southeastern Louisiana (Esri polyline shapefile, GCS WGS 84) Isopachs--Point Conception to Hueneme Canyon, California Transgressive Contours--Point Conception to Hueneme Canyon, California Integration of bed characteristics, geochemical tracers, current measurements, and numerical modeling for assessing the provenance of beach sand in the San Francisco Bay Coastal System Sand sources and transport pathways for the San Francisco Bay coastal system, based on X-ray diffraction mineralogy Dune Metrics for the Massachusetts Coast as Derived From 2013–14 Topographic Lidar Data Isopachs—Point Sur to Point Arguello, California