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Results for “Geologie en Mijnbouw”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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7 recordsLinked to original sources
USGS1982

Velocity and bottom-stress measurements in the bottom boundary layer, outer Norton Sound, Alaska.

We have used long-term measurements of near-bottom velocities at four heights above the sea floor in Norton Sound, Alaska, to compute hourly values of shear velocity u., roughness and bottom-drag coefficient. Maximum sediment resuspension and transport, predicted for periods when the computed value of u. exceeds a critical level, occur during peak tidal currents associated with spring tides. The fortnightly variation in u. is correlated with a distinct nepheloid layer that intensifies and thickens during spring tides and diminishes and thins during neap tides. The passage of a storm near the end of the experiment caused significantly higher u. values than those found during fair weather.-from Authros

Geologie en Mijnbouw↗
USGS1982

Variation in sand body types on the eastern Bering Sea epicontinental shelf.

The eastern epicontinental shelf of the Bering Sea is characterized by variations in river and glacial sediment supply, wave energy, tidal range (microtidal to mesotidal), and tidal, geostrophic, and storm-induced currents. These factors, combined with the effect of the Holocene rise in sea level, have resulted in the formation of a complex assemblage of generally linear sand bodies of similar morphology anad lithology, but different origins. The sand bodies are large features found from the present shoreline to tens of kilometers offshore, in water depths up to 50m. -from Authors

Geologie en Mijnbouw↗
USGS1982

Late Pleistocene- Holocene transgressive sedimentation in deltaic and non-deltaic areas of the northeastern Bering epicontinental shelf.

The distribution of late Pleistocene and Holocene surface sediments on the northern Bering Seafloor is patchy and dependent upon locations of seafloor bedrock and pre-late Pleistocene glacial debris, late Holocene river sediment influx, and modern strong bottom currents. Seafloor vibracores and high-resolution profiles record two different sedimentary environments in the northern Bering shelf: late Pleistocene-Holocene shoreline transgression in Chirikov Basin, and Holocene deposition from the Yukon River in Norton Sound.-from Author

Geologie en Mijnbouw↗
USGS1982

Microfaunal analysis of late Quaternary deposits of the northern Bering Sea.

Holocene microfaunal associations and distribution patterns define three inner-shelf (1-20m) biofacies in Norton Sound, northern Bering Sea. The Holocene facies relations are the basis for interpreting early Holocene and late Pleistocene environmental conditions in the NE Bering Sea area. Norton Sound cores provide evidence of two marine transgressions and a varying river input.-from Author

Geologie en Mijnbouw↗
USGS1982

Geotechnical characteristics of bottom sediments in the northeastern Bering Sea.

Sediment of Holocene age derived from the Yukon River, consisting dominantly of silty fine sand and sandy silt, covers the bottom of central and western Norton Sound, which is a high energy environment involving extensive ice loading, high waves, and strong bottom currents. The sediment characteristics indicate that it is susceptible to liquefaction during major storms. Substantially finer grained, weak and highly compressible sediment of Holocene age covers eastern Norton Sound and the Port Clarence embayment, which are low energy environments. Pleistocene peaty deposits underlie the Holocene and late Pleistocene deposits in both Norton Sound and Chirikov Basin and are somewhat overconsolidated. The presence of gas indicates high in situ pore pressure and hence low material strength.-from Authors

Geologie en Mijnbouw↗
USGS1981

Depositional and erosional features of the inner shelf, northeastern Bering Sea.

Sonographs and bathymetric profiles from water depths less than 15m in the Nome-Solomon, Port Clarence, and Yukon Delta areas of the Alaskan Bering Sea coast show features generated by waves, currents, and drifting ice. The surficial sediments in the Nome-Solomon and Port Clarence areas range in grain size from sand to boulder gravel and have many surface features visible on sonographs, whereas the sediments off the Yukon Delta are fine sands and silts that have few such features. Materials in the Nome-Solomon and Port Clarence areas have been seggregated by grain size into ribbons and irregular, elongate, and lobate patches. Coarse sand and fine gravel patches and ribbons are characterized by symmetrical ripples generated by storm waves. Ice-gouged furrows occur in all the nearshore areas studied.-from Authors

Geologie en Mijnbouw↗
USGS1982

Distribution of gas-charged sediment in Norton Sound and Chirikov Basin.

Numerous zone of anomalous acoustic resonses caused by gas in the subsurface sediment layers have been detected on seismic reflection records from Norton Sound and Chirikov Basin. The frequency and distribution of these zones suggest that as much as 7000km2 of the northeastern Bering Sea may be underlain by gas-charged sediment. Much of the gas is of shallow biogenic origin, having been generated in buried peat deposits. Seismic velocity beneath a large gas seep south of Nome decreases in the interval from 250 to 440m below the seafloor, where thermogenic gases of deeper origin are migrating upward along a system of basin margin faults.-from Authors

Geologie en Mijnbouw↗