Gravity and crustal structure in the western Snake River Plain, Idaho
A gravity survey was made over the western Snake River Plain, Idaho. The data were reduced to sea level and expressed as simple Bouguer gravity anomalies for an assumed density of 2.67 g/cm/sup 3/. Three elongated, northwesttrending, en echelon gravity highs were defined by the survey. The largest high is about 150 km long and 40 km wide; its maximum amplitude is 70 mgal. Application of limiting-depth methods implies that the tops of the disturbing bodies can be no deeper than 5 km below sea level. Two-dimensional analyses, based on a density contrast of 0.3 g/cm/sup 3/, indicate that the anomaly-causing bodies extend from near sea level to at least 6 km below sea level and possibly to as much as l8 km below sea level. The total mass excess of the disturbing bodies is estimated to be 1 x 10/sup 19/ g, and the corresponding volume for material 0.3 g/cm/sup 3/ more dense than the surrounding material is approximately 33,000 km/sup 3/. If the highlands on either side of the plain are regionally compensated, the crust under the plain is probably undercompensated by an amount proportional to the local anomalous bodies.
- Research Organization:
- Geological Survey, Denver
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-17-041005
- OSTI ID:
- 4689725
- Journal Information:
- Journal of Geophysical Research, Vol. 68, Issue 20; Other Information: Orig. Receipt Date: 31-DEC-63; ISSN 0148-0227
- Publisher:
- American Geophysical Union
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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