| Abstract: | A geophysical investigation was undertaken as part of an effort to characterize the geologic framework influencing ground-water resources in east-central Nevada and west-central Utah. New gravity data were combined with existing aeromagnetic, drill-hole, and geologic data to help determine basin geometry, infer structural features, estimate depth to pre-Cenozoic basement rocks, and further constrain the horizontal extents of exposed and buried plutons. In addition, a three-dimensional (3D) geologic model was constructed to help illustrate the often complex geometries of individual basins and aid in assessing the connectivity of adjacent basins. In general, the thirteen major valleys within the study area have axes oriented north-south and frequently contain one or more sub-basins. These basins are often asymmetric and typically reach depths of 2 km. Analysis of gravity data helped delineate geophysical lineaments and accommodation zones. Structural complexities may further compartmentalize ground-water flow within basins and the influence of tectonics on basin sedimentation further complicates their hydrologic properties.
The horizontal extent of exposed and, in particular, buried plutons was estimated over the entire study area. The location and subsurface extents of these plutons will be very important for regional water resource assessments, as these features may act as either barriers or pathways for groundwater flow. A previously identified basement gravity low strikes NW within the study area and occurs within a highly extended terrane between the Butte and Confusion synclinoria. Evidence from geophysical, geologic, and seismic reflection data suggests relatively lower density plutonic rocks may extend to moderate crustal depths and rocks of similar composition may be the source of the entire basement gravity anomaly. |
| Genre: | USGS Numbered Series |
| ProdID: | 80394 |
| Citation Author: | Watt, Janet T.; Ponce, David A. |
| Citation Contributing Office: | USGS Geophysics Unit of Menlo Park, California |
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| Citation Day: | |
| Citation Edition: | Version 1.0 |
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| Citation Language: | ENGLISH |
| Citation Larger Work Title: | |
| Citation LatN: | 0403000 |
| Citation LatS: | 0370000 |
| Citation LonE: | -1130000 |
| Citation LonW: | -1163000 |
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| Citation No Pagination: | N |
| Citation Number Of Pages: | |
| Citation Online Only Flag: | Y |
| Citation Phsyical Description: | Report: iv, 43 p. (With a section on
Geologic and Geophysical Basin-by-basin Descriptions
by Alan R. Wallace, Janet T. Watt, and David A. Ponce); 2 Plates: each 18 x 24 inches |
| Citation Projection: | |
| Citation Public Comments: | Prepared in cooperation with the Bureau of Land Management (BLM) |
| Citation Publisher: | Geological Survey (U.S.) |
| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 2007-1163 |
| Citation Search Results Text: | Geophysical Framework Investigations Influencing Ground-Water Resources in East-Central Nevada and West-Central Utah; 2007; OFR; 2007-1163; Watt, Janet T.; Ponce, David A. |
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| Citation Year: | 2007 |
| Type: | citation/reference |
| Text: | Geophysical Framework Investigations Influencing Ground-Water Resources in East-Central Nevada and West-Central Utah; 2007; OFR; 2007-1163; Watt, Janet T.; Ponce, David A. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/of/2007/1163/ |
| Date Other: | Sat, 22 Sep 2007 00:00 -0500 |
| Publisher: | Geological Survey (U.S.) |
