| Abstract: | Interpretations of gravity and aeromagnetic anomaly data, supplemented by results from two seismic reflection profiles and five magnetotelluric soundings, were used to study buried structure and lithology of the Libby thrust belt of northwestern Montana. The gravity anomaly data show a marked correlation with major structures. The Purcell anticlinorium and the Sylvanite anticline are very likely cored by stacks of thrust slices of dense crystalline basement rocks that account for the large gravity highs across these two structures. Gravity anomaly data for the Cabinet Mountains Wilderness show a string of four broad highs. The principal magnetic anomaly sources are igneous intrusive rocks, major fault zones, and magnetite-bearing sedimentary rocks of the Ravalli Group. The most important magnetic anomalies in the principal study area are five distinct positive anomalies associated with Cretaceous or younger cupolas and stocks. |
| Genre: | USGS Numbered Series |
| ProdID: | 6130 |
| Citation Author: | Kleinkopf, M. Dean; with sections by Harrison, Jack Edward; Stanley, W. D. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | 22 p.; 2 plates in pocket |
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| Citation Publisher: | U.S. G.P.O., |
| Citation Series: | Professional Paper |
| Citation Series Code: | PP |
| Citation Series Number: | 1546 |
| Citation Search Results Text: | Geophysical interpretations of the Libby thrust belt, northwestern Montana; 1997; PP; 1546; Kleinkopf, M. Dean; with sections by Harrison, Jack Edward; Stanley, W. D. |
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| Citation Year: | 1997 |
| Type: | citation/reference |
| Text: | Geophysical interpretations of the Libby thrust belt, northwestern Montana; 1997; PP; 1546; Kleinkopf, M. Dean; with sections by Harrison, Jack Edward; Stanley, W. D. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/pp_1546.jpg |
| URL (INDEX PAGE): | http://pubs.usgs.gov/pp/p1546/ |
| URL (PLATE): | http://pubs.usgs.gov/pp/1546/plate-1.pdf |
| URL (PLATE): | http://pubs.usgs.gov/pp/1546/plate-2.pdf |
| URL (INDEX PAGE): | http://ngmdb.usgs.gov/Prodesc/proddesc_13146.htm |
| Date Other: | Sat, 1 Nov 1997 00:00 -0600 |
| Publisher: | U.S. G.P.O., |
