| Abstract: | An inverted metamorphic gradient is preserved in the western metamorphic belt near Juneau, Alaska. Detailed mapping of pelitic single-mineral isograds, systematic changes in mineral assemblages, and silicate geothermometry indicate that thermal peak metamorphic conditions increase structurally upward over a distance of about 8 km. Silicate geobarometry suggests that the thermal peak metamorphism occurred under pressures of 9-11 kbar. Our preferred interpretation of the cause of the inverted gradient is that it formed during compression of a thickened wedge of relatively wet and cool rocks in response to heat flow associated with the formation and emplacement of tonalite sill magma. -from Authors |
| Genre: | Article |
| ProdID: | 70016798 |
| Citation Author: | Himmelberg, G. R.; Brew, D. A.; Ford, A. B. |
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| Citation End Page: | 180 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Metamorphic Geology |
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| Citation Number Of Pages: | 16 |
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| Citation Search Results Text: | Development of inverted metamorphic isograds in the western metamorphic belt, Juneau, Alaska; 1991; Article; Journal; Journal of Metamorphic Geology; Himmelberg, G. R.; Brew, D. A.; Ford, A. B. |
| Citation Start Page: | 165 |
| Citation Volume: | 9 |
| Citation Year: | 1991 |
| Type: | citation/reference |
| Text: | Development of inverted metamorphic isograds in the western metamorphic belt, Juneau, Alaska; 1991; Article; Journal; Journal of Metamorphic Geology; Himmelberg, G. R.; Brew, D. A.; Ford, A. B. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 1 Jan 1991 00:00 -0600 |
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