| Abstract: | The U-Pb and K-Ar geochronology applied to intrusive rocks from the Coastal Batholith of Central Chile, demonstrates the existence of a basement block of the Mirasol Unit, with a crystallization age of 299??10 Ma, exposed in the northern block of the Melipilla Fault. The age of 214??1 Ma obtained in the ‘Dioritas Gne??isicas de Cartagena Unit‘, indicates that a Late Triassic magmatism took place in this region; it coincides with the end of an extensive crustal melting period, proposed for northern Chile. The ages of the Jurassic plutonic units (Laguna Verde, Sauce, Pen??uelas and Limache) are restricted to the 156-161 Ma interval, showing in certain cases, inherited zircons from an unknown source. The difference between ages obtained using both chronological methods is a few million years, indicating that a short time passed between the crystallization and the cooling of the plutonic bodies, as well as a fast magmatic differentiation process. The Laguna Verde and Sauce Units, experienced a fast uplift, probably as a result of an extensional tectonic process in the magmatic arc, or induced by the magmatic pressure through fracture zones during Middle Jurassic. |
| Genre: | Article |
| ProdID: | 70018631 |
| Citation Author: | Gana, P.; Tosdal, R. M. |
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| Citation End Page: | 164 |
| Citation Issue: | 2 |
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| Citation Language: | Spanish |
| Citation Larger Work Title: | Revista Geologica de Chile |
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| Citation Number Of Pages: | 14 |
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| Citation Search Results Text: | U-Pb and K-Ar geochronology in Paleozoic and Mesozoic intrusive rocks of the Coastal Cordillera, Valparai??so, Chile [Geocronologi??a U-Pb y K-Ar en intrusivos del Paleozoico y Mesozoico de la Cordillera de la Costa, Regio??n de Valparai??so, Chile]; 1996; Article; Journal; Revista Geologica de Chile; Gana, P.; Tosdal, R. M. |
| Citation Start Page: | 151 |
| Citation Volume: | 23 |
| Citation Year: | 1996 |
| Type: | citation/reference |
| Text: | U-Pb and K-Ar geochronology in Paleozoic and Mesozoic intrusive rocks of the Coastal Cordillera, Valparai??so, Chile [Geocronologi??a U-Pb y K-Ar en intrusivos del Paleozoico y Mesozoico de la Cordillera de la Costa, Regio??n de Valparai??so, Chile]; 1996; Article; Journal; Revista Geologica de Chile; Gana, P.; Tosdal, R. M. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1996 00:00 -0600 |
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