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At least 829 records · Page 46Linked to original sources
USGS2003

Geophysical surveys of Bear Lake, Utah-Idaho, September, 2002

The U.S. Geological Survey, in cooperation with researchers from several universities, has been studying the sediments of Bear Lake since 1996. The general purpose of this effort is to reconstruct past limnological conditions and regional climate on a range of timescales, from hundreds of years to hundreds of thousands of years. The objectives of the September, 2002 operations, preliminarily reported here, were (1) to compile a detailed bathymetric map of the lake using swath-mapping techniques, in order to provide baseline data for a variety of applications and studies, and (2) to complete a sidescan-sonar survey of the lake, providing a nearly complete acoustic image of the lake floor. Limited amounts of subbottom acoustic-reflection data (chirp) were also collected, along with samples of lake-floor sediments representative of different kinds of backscatter patterns.

Idaho, Utah↗
USGS2005

Lake Mohave Geophysical Survey 2002: GIS Data Release

This CD-ROM contains sidescan-sonar imagery, sub-bottom reflection profiles, and an interpretive map derived from these data. These data were collected in Lake Mohave, a reservoir behind the Davis Dam and below the Hoover Dam on the Colorado River. These data are veiwable within an Environmental system Research Institute, Inc. (ESRI) Geographic Information system (GIS) ArcView 3.2 project file stored on this CD-ROM

Open-File Report↗
USGS2006

GIS of selected geophysical and core data in the northern Gulf of Mexico continental slope collected by the U.S. Geological Survey

Since 1982 the U. S. Geological Survey (USGS) has collected a large amount of surficial and shallow subsurface geologic information in the deep-water parts of the US EEZ in the northern Gulf of Mexico. These data include digital sidescan sonar imagery, digital seismic-reflection data, and descriptions and analyses of piston and gravity cores. The data were collected during several different projects that addressed surficial and shallow subsurface geologic processes. Some of these datasets have already been published, but the growing interest in the occurrence and distribution of gas hydrates in the Gulf of Mexico warrants integrating these existing USGS datasets and associated interpretations into a Geographic Information System (GIS) to provide regional background information for ongoing and future gas hydrate research. This GIS is organized into five different components that contain (1) information needed to develop an assessment of gas hydrates, (2) background information for the Gulf of Mexico, (3) cores collected by the USGS, (4) seismic surveys conducted by the USGS, and (5) sidescan sonar surveys conducted by the USGS. A brief summary of the goals and findings of the USGS field programs in the Gulf of Mexico is given in the Geologic Findings section, and then the contents of each of the five data categories are described in greater detail in the GIS Data Catalog section.

Gulf of Mexico↗
USGS2006

A Preliminary Investigation of The Structure of Southern Yucca Flat, Massachusetts Mountain, and CP Basin, Nevada Test Site, Nevada, Based on Geophysical Modeling

New gravity and magnetic data collected in the vicinity of Massachusetts Mountain and CP basin (Nevada Test Site, NV) provides a more complex view of the structural relationships present in the vicinity of CP basin than previous geologic models, helps define the position and extent of structures in southern Yucca Flat and CP basin, and better constrains the configuration of the basement structure separating CP basin and Frenchman Flat. The density and gravity modeling indicates that CP basin is a shallow, oval-shaped basin which trends north-northeast and contains ~800 m of basin-filling rocks and sediment at its deepest point in the northeast. CP basin is separated from the deeper Frenchman Flat basin by a subsurface ridge that may represent a Tertiary erosion surface at the top of the Paleozoic strata. The magnetic modeling indicates that the Cane Spring fault appears to merge with faults in northwest Massachusetts Mountain, rather than cut through to Yucca Flat basin and that the basin is downed-dropped relative to Massachusetts Mountain. The magnetic modeling indicates volcanic units within Yucca Flat basin are down-dropped on the west and supports the interpretations of Phelps and KcKee (1999). The magnetic data indicate that the only faults that appear to be through-going from Yucca Flat into either Frenchman Flat or CP basin are the faults that bound the CP hogback. In general, the north-trending faults present along the length of Yucca Flat bend, merge, and disappear before reaching CP hogback and Massachusetts Mountain or French Peak.

Open-File Report↗
USGS2006

Geographic information systems (GIS) spatial data compilation of geodynamic, tectonic, metallogenic, mineral deposit, and geophysical maps and associated descriptive data for northeast Asia

This is the online version of a CD-ROM publication. It contains all of the data that are on the disc but extra files have been removed: index files, software installers, and Windows autolaunch files. The purpose of this publication is to provide a high-quality spatial data compilation (Geographical Information System or GIS) of geodynamic, mineral deposit, and metallogenic belt maps, and descriptive data for Northeast Asia for customers and users. This area consists of Eastern Siberia, Russian Far East, Mongolia, northern China, South Korea, and Japan. The GIS compilation contains integrated spatial data for: (1) a geodynamics map at a scale of 1:5,000,000; (2) a mineral deposit location map; (3) metallogenic belt maps; (4) detailed descriptions of geologic units, including tectonostratigraphic terranes, cratons, major melange zones, and overlap assemblages, with references; (5) detailed descriptions of metallogenic belts with references; (6) detailed mineral deposit descriptions with references; and (7) page-size stratigraphic columns for major terranes.

Open-File Report↗