| Abstract: | Quantitative limonite mapping within the leached capping of the porphyry copper deposit at La Escondida, Chile, permits reconstruction of the paleohydrologic and chemical evolution of a well-developed supergene ore-forming system. The mineralogy, textures, and relative abundance of supergene limonite minerals (hematite, goethite, and jarosite) are used to reconstruct the former ratio of pyrite to chalcocite and the preoxidation copper grade based on empirical limonite sulfide correlations. Evidence for cumulative downward enrichment in vertical profiles through leached capping allows quantitative analysis of chemical mass balance in dynamic supergene systems. Slopes of linear regressions for profiles of reconstructed enriched copper grades vs. depth indicate lateral fluxes into or out of a given vertical profile. -from Authors |
| Genre: | Article |
| ProdID: | 70015390 |
| Citation Author: | Alpers, C. N.; Brimhall, G. H. |
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| Citation End Page: | 255 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Economic Geology |
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| Citation Number Of Pages: | 27 |
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| Citation Search Results Text: | Paleohydrologic evolution and geochemical dynamics of cumulative supergene metal enrichment at La Escondida, Atacama Desert, northern Chile; 1989; Article; Journal; Economic Geology; Alpers, C. N.; Brimhall, G. H. |
| Citation Start Page: | 229 |
| Citation Volume: | 84 |
| Citation Year: | 1989 |
| Type: | citation/reference |
| Text: | Paleohydrologic evolution and geochemical dynamics of cumulative supergene metal enrichment at La Escondida, Atacama Desert, northern Chile; 1989; Article; Journal; Economic Geology; Alpers, C. N.; Brimhall, G. H. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sun, 1 Jan 1989 00:00 -0600 |
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