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| Format: | Artículo científico |
| Langue: | en |
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Asociación Argentina de Sedimentología
2009
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| Accès en ligne: | https://www.redalyc.org/articulo.oa?id=381740363003 |
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Table des matières:
- THE AREQUITA FORMATION (LOWER CRETACEOUS): PETROGRAPHIC FEATURES OF THE VOLCANIC FACIES IN THE LAGUNA MERÍN BASIN, EAST URUGUAY Rossana MUZIO Ethel MORALES Gerardo VEROSLAVSKY Bruno CONTI Ciencias de la Tierra Uruguay Mesozoic rhyolites petrography ignimbrites The southeastern border of the Laguna Merín Basin (Rocha Department, East Uruguay) consists of Mesozoic volcanic deposits of the Puerto Gómez and Arequita formations, overlain by a sedimentary cover of Cenozoic and recent deposits. Well- preserved lava flow and pyroclastic deposits have been identified in the Arequita Formation after detailed mapping (1.50.000) in Sierra de los Ajos region. The present study focuses on the petrographic characterization of this felsic volcanism, with special emphasis on the pyroclastic units. Differences in the structural and petrographic distribution of these volcanic units are related to the N20ºE trending India Muerta Lineament. East of this lineament, SiO2-rich rhyolites and pyroclastic deposits (ignimbrites) are present whereas to the west, the volcanic rocks are mainly represented by basic to felsic lavas. Based on petrographic features and regional distribution, explosive mechanisms have been assigned to some of the volcanic units, interpreted as pyroclastic flow and pyroclastic surge deposits. 2009 artículo científico 1851-4979 https://www.redalyc.org/articulo.oa?id=381740363003 en http://www.redalyc.org/revista.oa?id=3817 Latin American Journal of Sedimentology and Basin Analysis application/pdf Asociación Argentina de Sedimentología Latin American Journal of Sedimentology and Basin Analysis (Argentina) Num.1 Vol.16