Depositos sinorogenicos en el antepais neopaleozoico del cinturon de Famatina, centro-oeste de Argentina: implicancias paleoambientales, paleogeografias y tectonosedimentarias.Synorogenic deposits in the late Paleozoic foreland basin of central-western Argentina: paleoenvir-onments, paleogeography and tectosedimentary implications.
Synorogenic deposits in the late Paleozoic foreland basin of central-western Argentina: paleoenvironments, paleogeography and tectosedimentary implications
| dc.contributor | en-US | |
| dc.creator | Ezpeleta, Miguel | |
| dc.creator | Astini, Ricardo A. | |
| dc.creator | Davila, Federico | |
| dc.date | 2010-06-21 | |
| dc.identifier | http://www.andeangeology.cl/index.php/revista1/article/view/V35n2-a04 | |
| dc.identifier | 10.5027/andgeoV35n2-a04 | |
| dc.description | RESUMEN:En el cinturon de Famatina, ubicado entre las provincias geologicas argentinas de Sierras Pampeanas y Precordillera, se describe y analiza una sucesion de conglomerados de -400 m, considerada en trabajos previos como la seccion superior del intervalo postglacial neopaleozoico del Grupo Paganzo (Pensilvaniano tardio). En este trabajo estos conglomerados (Formacion Las Pircas nom.nov.), extensamente desarrollados en Famatina, son separados como una unidad litoestratigrafica diferente asociada a un episodio de deformacion, sobre la base de: 1. la presencia de una discordancia angular en su base, 2. un fuerte contraste litofacial con la unidad glacial subyacente y 3. su organizacion estratigrafica interna. El analisis de facies indica un predominio de depositos de abanicos aluviales proximales, que pasan en transicion hacia sistemas fluviales entrelazados y desarrollo local de depositos lacustres. La recurrencia de megacapas con bloques y conglomerados de composicion granitica indica una significativa exhumacion de basamento, sugiriendo actividad tectonica coetanea. Asimismo, los estudios de procedencia indican participacion de clastos de areniscas fluviales pensilvanianas y volcanitas acidas ordovicicas que actualmente se exponen en la sierra de Famatina. Esto es compatible con el analisis de paleocorrientes, que muestra una dispersion de los sedimentos hacia el oeste. La posicion de los altos topograficos de basamento al este del arco principal, junto con evidencias de plegamiento, sugieren una etapa de deformacion de zocalo dentro del antepais no descrita con anterioridad. Esto permite explicar la fuente principal de esta cuña clastica depositada de este a oeste parcialmente equivalente a la Formacion Tupe en el ambito de Precordillera. Este modelo de antepais puede ser comparado con el antepais fragmentado moderno de los Andes Centrales.ABSTRACT:In the Famatina belt, western Argentina, a -400 m thick conglomerate succession is extensively developed and has been previously considered as the uppermost section of a postglacial interval (late Pennsylvanian) of the Paganzo Group. Here we separate it as a different lithostratigraphic unit (Las Pircas Formation, nom. nov.) with a significant tectonic meaning based on: 1. the angular discordance at its base; 2. the strong lito facial contrast with the underlying glacial unit and 3. its internal stratigraphic organization. Facies analyses indicate topographically controlled proximal alluvial fans succeeded by braided fluvial systems, and local development of lacustrine deposits. Granite bearing-megaboulder beds and conglomerates indicate significant basement exhumation and tectonic unroofing. Clast composition also depicts early Pennsylvanian sandstones and Ordovician volcanic rocks mainly exposed in the central part of Famatina (at present). Paleocurrent analyses are compatible with a dispersal pattern mostly to the west. The position of basement topographic high further east from the main contemporaneous arc together with evidences of folding allow us to interpret previously unrecognized basement thrusting within the foreland. This may have been the main source for the westward coarse arkosic clastic wedge known in the Argentine Precordillera as the Tupe Formation and equivalents. This late Pennsylvanian-Early Permian foreland model can be compared with the modern broken foreland of the Central Andes. | es-ES |
| dc.description | In the Famatina belt, western Argentina, a -400 m thick conglomerate succession is extensively developed and has been previously considered as the uppermost section of a postglacial interval (late Pennsylvanian) of the Paganzo Group. Here we separate it as a different lithostratigraphic unit (Las Pircas Formation, nom. nov.) with a significant tectonic meaning based on: 1. the angular discordance at its base; 2. the strong lito facial contrast with the underlying glacial unit and 3. its internal stratigraphic organization. Facies analyses indicate topographically controlled proximal alluvial fans succeeded by braided fluvial systems, and local development of lacustrine deposits. Granite bearing-megaboulder beds and conglomerates indicate significant basement exhumation and tectonic unroofing. Clast composition also depicts early Pennsylvanian sandstones and Ordovician volcanic rocks mainly exposed in the central part of Famatina (at present). Paleocurrent analyses are compatible with a dispersal pattern mostly to the west. The position of basement topographic high further east from the main contemporaneous arc together with evidences of folding allow us to interpret previously unrecognized basement thrusting within the foreland. This may have been the main source for the westward coarse arkosic clastic wedge known in the Argentine Precordillera as the Tupe Formation and equivalents. This late Pennsylvanian-Early Permian foreland model can be compared with the modern broken foreland of the Central Andes. | en-US |
| dc.format | application/pdf | |
| dc.format | text/html | |
| dc.language | eng | |
| dc.publisher | Servicio Nacional de Geología y Minería | en-US |
| dc.relation | http://www.andeangeology.cl/index.php/revista1/article/view/V35n2-a04/423 | |
| dc.relation | http://www.andeangeology.cl/index.php/revista1/article/view/V35n2-a04/html | |
| dc.source | Andean Geology; Vol 35, No 2 (2008); 253-278 | es-ES |
| dc.source | Andean Geology; Vol 35, No 2 (2008); 253-278 | en-US |
| dc.source | 0718-7106 | |
| dc.source | 0718-7092 | |
| dc.title | Depositos sinorogenicos en el antepais neopaleozoico del cinturon de Famatina, centro-oeste de Argentina: implicancias paleoambientales, paleogeografias y tectonosedimentarias.Synorogenic deposits in the late Paleozoic foreland basin of central-western Argentina: paleoenvir-onments, paleogeography and tectosedimentary implications. | es-ES |
| dc.title | Synorogenic deposits in the late Paleozoic foreland basin of central-western Argentina: paleoenvironments, paleogeography and tectosedimentary implications | en-US |
| dc.type | info:eu-repo/semantics/article | |
| dc.type | info:eu-repo/semantics/publishedVersion | |
| dc.type | es-ES | |
| dc.type | en-US |
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Andean Geology
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