| Abstract: | Electromagnetic induction data using distant field sources, mostly of natural origin, in the frequency range of 4.5-27,000 Hz are analyzed to depict the geoelectric structure in an area of volcanic-rock cover located in southeastern Arizona between the Morenci and Safford porphyry copper deposits. The data for each station consist of scalar electromagnetic measurements at descrete frequencies for two-orthogonal magnetic and electric field pairs. Observations spaced about 5-km apart indicate resistivities in the range of 100-700 ohm-m for the unweathered Tertiary volcanic rocks to a depth of 200 to 500 m. Beneath this zone the data indicate resistivities in the range of 10-100 ohm-m that suggest the existence of an older volcanic rock unit. The less resistive unit appears to be displaced upward beneath Turtle Mountain, an area bounded to the northeast and southwest by mapped Basin and Range faults, and bounded to the southeast by an unmapped fault of older origin that trends northeast. Lateral changes in the resistivity of the two main geoelectric layers result in lowered resistivity in an area of known hot-springs near the confluence of the Gila and San Francisco Rivers, as well as along a north-south trending zone located on the east flank of Turtle Mountain, about 5-km (3-mi) west-northwest of the hot springs. This second anomaly is at a probable depth of 400-500 m and is interpreted to indicate a buried fault or fracture zone. |
| Genre: | USGS Numbered Series |
| ProdID: | 19670 |
| Citation Author: | Klein, D. P.; Baer, M. J. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | 1 v. 107 p. :ill., maps ;28 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 83-815 |
| Citation Search Results Text: | Geoelectric structure of the Gila-San Francisco Wilderness Area, Graham and Greenlee counties, Arizona from audio-magnetotelluric data; 1983; OFR; 83-815; Klein, D. P.; Baer, M. J. |
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| Citation Year: | 1983 |
| Type: | citation/reference |
| Text: | Geoelectric structure of the Gila-San Francisco Wilderness Area, Graham and Greenlee counties, Arizona from audio-magnetotelluric data; 1983; OFR; 83-815; Klein, D. P.; Baer, M. J. |
| URL (THUMBNAIL): | http://pubs.usgs.gov/of/1983/0815/report-thumb.jpg |
| URL (DOCUMENT): | http://pubs.usgs.gov/of/1983/0815/report.pdf |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
