Stratigraphy and Petrography of Igneous Rocks in the Upper Part of the Talamanca Cordillera, Costa Rica
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| Autoři: | , , , , |
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| Médium: | artículo original |
| Stav: | Versión publicada |
| Datum vydání: | 2018 |
| Popis: | In the Talamanca Cordillera, the widespread magmatic products record Neogene and Quaternary intrusive and extrusive phases. Generally, it is possible to recognize three magmatic stages: 1) Volcanic series older than Upper Miocene, ranging from ~17 to 11 mya; 2) Plutonic events during the Middle-Upper Miocene, between 12,5 and 7,5 mya, known as Talamanca Intrusive Group or Granite-Gabbro Series of Talamanca; c) Post-intrusive magmatic pulses from Neogene-Quaternary, whose temporal range extends from ~5 to 2 mya. For the first time it is proposed here a differentiation of post-intrusive magmas into three units by petrographic criteria: a) Kamuk Unit, andesites with labradorite-type plagioclase and occasional orthopyroxene. b) Durika Unit, defined by andesine-type plagioclase and the presence of biotite phenocrysts as the predominant ferromagnesian phase. c) Rio Lori Unit, whose products were not sampled in this study, but based in previous work they are characterized by the presence of quartz, amphibole and biotite phenocrysts. Additionally, we provide a new contribution to the geologic cartography of the Talamanca Cordillera, with a geological description of the summits of Cuericí, Ena, Dúrika, Utyum, Kámuk, fila Pittier and Echandi. We also present new data referring to the geology of the summit of Chirripo. |
| Země: | Portal de Revistas UCR |
| Instituce: | Universidad de Costa Rica |
| Repositorio: | Portal de Revistas UCR |
| Jazyk: | Español |
| OAI Identifier: | oai:portal.ucr.ac.cr:article/32669 |
| On-line přístup: | https://revistas.ucr.ac.cr/index.php/geologica/article/view/32669 |
| Klíčové slovo: | Basalt quartz monzonite orthopyroxene andesite biotite latite dacite Basalto monzonita cuarzosa ortopiroxeno andesita biotita latita dacita |