| Abstract: | Schwartzwalder ores have high amounts of initial (common) Pb that was both variable and relatively radiogenic in its isotope ratios. Assuming the common Pb in these ores to have sources of similar age and similar Th/U, samples with initial Pb isotope ratios are identified - and others with variable initial ratios are normalized - to obtain U-Pb isochrons yielding an early Laramide age of 69.3 + or - 1.1 m.y. for the ores. The initial Pb-isotope systematics indicate local sources of U, dispersed in concentrations <100 ppm, in rocks of 1730 + or - 130 m.y. age. -G.J.N. |
| Genre: | Article |
| ProdID: | 70013073 |
| Citation Author: | Ludwig, K. R.; Wallace, A. R.; Simmons, K. R. |
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| Citation End Page: | 1871 |
| Citation Issue: | 7 |
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| Citation Language: | English |
| Citation Larger Work Title: | Economic Geology |
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| Citation Number Of Pages: | 14 |
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| Citation Search Results Text: | The Schwartzwalder uranium deposit, II: Age of uranium mineralization and lead isotope constraints on genesis.; 1985; Article; Journal; Economic Geology; Ludwig, K. R.; Wallace, A. R.; Simmons, K. R. |
| Citation Start Page: | 1858 |
| Citation Volume: | 80 |
| Citation Year: | 1985 |
| Type: | citation/reference |
| Text: | The Schwartzwalder uranium deposit, II: Age of uranium mineralization and lead isotope constraints on genesis.; 1985; Article; Journal; Economic Geology; Ludwig, K. R.; Wallace, A. R.; Simmons, K. R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 1 Jan 1985 00:00 -0600 |
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