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| Formato: | Artículo científico |
| Lenguaje: | en |
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Universidad Nacional Autónoma de México
2008
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| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=57225103 |
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- Transitional adakite-like to calc-alkaline magmas in a continental extensional setting at La Paz Au-Cu skarn deposits, Mesa Central, Mexico: metallogenic implications Víctor A. Valencia Porfirio J. Pinto Linares Gilles Levresse José M. Torres Aguilera David Estrada Jordi Tritlla Manuel González Ciencias de la Tierra Au Pb like La Paz Mexico The granodiorite intrusions with associated Cu-Au skarn mineralization of La Paz district arelocated in the east part of the Mesa Central of Mexico. The skarn developed at the contact between amiddle Cretaceous calc-argillaceous sedimentary sequence and the magmatic intrusions. A Ag-Pb-Zn veinsystem postdates the intrusive-skarn assemblage. Two well defined fault systems (N-S and E-W) dividethe La Paz district. The N-S Dolores fault, with a normal vertical displacement estimated between 500 to1000 m, separates the western Au-Cu skarn zone from the eastern hydrothermal Ag-Pb-Zn vein system.This fault is considered to be part of the Taxco-San Miguel de Allende fault system. The U-Pb datingof the intrusives at the La Paz district clearly indicates a single emplacement event dated at ca. 37 Ma(monocrystal zircon age). This age probably represents the last post-Laramide orogenic mineralizingevent known to occur in the Sierra de Catorce district. Also, four calculated discordant ages suggest thepresence of greenvilian basement underneath a a thick crust (35-45 km).The chemistry of the intrusive show a certain variability in composition, but they mostly belong tothe high-K calc-alkaline magmatic series. Major and trace elements relationships for the intrusives showa chemical evolution from the adakite to the island arc fields, and from mineralized to barren intrusives,repectively. They also suggest the importance of crustal delamination processes, and the necessity ofdeep cortical drains to transfer oxidized magmas and metals to surface 2008 artículo científico 1026-8774 https://www.redalyc.org/articulo.oa?id=57225103 en http://www.redalyc.org/revista.oa?id=572 Revista Mexicana de Ciencias Geológicas application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Ciencias Geológicas (México) Num.1 Vol.25