| Abstract: | Mesothermal, gold-bearing quartz veins are widespread within allochthonous terranes of Alaska that are composed dominantly of greenschist-facies metasedimentary rocks. The most productive lode deposits are concentrated in south-central and southeastern Alaska; small and generally nonproductive gold-bearing veins occur upstream from major placer deposits in interior and northern Alaska. Ore-forming fluids in all areas are consistent with derivation from metamorphic devolatilisation reactions, and a close temporal relationship exists between high-T tectonic deformation, igneous activity, and gold mineralization. Ore fluids were of consistently low salinity, CO2-rich, and had ??18O values of 7 ???-12??? and ??D values between -15??? and -35???. Upper-crustal temperatures within the metamorphosed terranes reached at least 450-500??C before onset of significant gold-forming hydrothermal activity. In southern Alaska, gold deposits formed during latter stages of Tertiary, subduction-related, collisional orogenesis and were often temporally coeval with calc-alkaline magmatism. -from Authors |
| Genre: | Article |
| ProdID: | 70017985 |
| Citation Author: | Goldfarb, R. J.; Snee, L. W.; Pickthorn, W. J. |
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| Citation End Page: | 394 |
| Citation Issue: | 3 |
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| Citation Language: | English |
| Citation Larger Work Title: | Mineralogical Magazine |
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| Citation Number Of Pages: | 20 |
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| Citation Search Results Text: | Orogenesis, high-T thermal events, and gold vein formation within metamorphic rocks of the Alaskan Cordillera; 1993; Article; Journal; Mineralogical Magazine; Goldfarb, R. J.; Snee, L. W.; Pickthorn, W. J. |
| Citation Start Page: | 375 |
| Citation Volume: | 57 |
| Citation Year: | 1993 |
| Type: | citation/reference |
| Text: | Orogenesis, high-T thermal events, and gold vein formation within metamorphic rocks of the Alaskan Cordillera; 1993; Article; Journal; Mineralogical Magazine; Goldfarb, R. J.; Snee, L. W.; Pickthorn, W. J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Fri, 1 Jan 1993 00:00 -0600 |
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