%0 Journal Article
%T The Lautaro Basin: A record of inversion tectonics in northern Chile La Cuenca Lautaro: un registro de inversi車n tect車nica en el norte de Chile
%A Fernando Mart赤nez
%A C谷sar Arriagada
%A Constantino Mpodozis
%A Mat赤as Peˋa
%J Andean Geology
%D 2012
%I Servicio Nacional de Geolog赤a y Miner赤a (SERNAGEOMIN)
%X The Triassic and Jurassic tectonic history of northern Chile has been dominated by extension, although clear evidence about the nature and geometry of the extensional basins and subsequent inversion structures has been adequately illustrated in only a few cases. In this contribution we present a structural study of the Lautaro Basin located at the western edge of the Frontal Cordillera in the Atacama region of northern Chile. The Lautaro Basin is a Jurassic half-graben, filled by at least 2,600 m of marine deposits of the Lautaro Formation and developed on top of, at least 2,000 m of Triassic volcanic successions of the La Ternera Formation, also accumulated during an earlier period of extensional deformation. Detailed field mapping and construction of a regional balanced cross-section, supported by good exposures along the Copiap車 River valley, allow reconstruction of the structural style of both the Jurassic and Triassic extensional depocenters. New structural data have shown that the Lautaro Basin has a complex structural framework reflected in two major Mesozoic extensional periods, overprinted by Cenozoic inversion involving thin- and thick-skinned tectonics. Shortening was accommodated by a combination of inversion of pre-existing normal faults, buttresses, development of footwall short-cuts, and both thin and thick-skinned thrusting. New estimates of shortening are up to 13.1 km (30%), while Mesozoic extension is estimated to be 3 km (7%). Durante el Tri芍sico y Jur芍sico la evoluci車n tect車nica del norte de Chile fue dominada por extensi車n cortical. No obstante, evidencias claras acerca del estilo estructural y subsecuente inversi車n de las cuencas asociadas con el evento extensional, han sido ilustradas en pocos casos. En este trabajo, se presenta un estudio estructural de la Cuenca Lautaro, localizada en el borde occidental de la Cordillera Frontal, en la regi車n de Atacama del norte de Chile. La Cuenca Lautaro, es un hemigraben que aloja al menos 2.600 m de dep車sitos marinos de la Formaci車n Lautaro, acumulados sobre al menos 2.000 m de sucesiones volc芍nicas tri芍sicas de la Formaci車n La Ternera. Los excelentes afloramientos de la regi車n permitieron construir una secci車n balanceada y restaurar el estilo estructural de los depocentros extensionales tri芍sicos y jur芍sicos. Los resultados obtenidos muestran que la Cuenca Lautaro tiene una arquitectura estructural compleja, reflejada en dos episodios extensionales mayores. Posteriormente, se sobreimpone al menos un evento de inversi車n tect車nica que desarrolla una tect車nica mixta de piel fina y piel grues
%K Cuenca Lautaro
%K Hemigraben
%K Secci車n balanceada
%K Inversi車n tect車nica
%K Norte chileno
%K Lautaro Basin
%K Half-graben
%K Balanced cross section
%K Inversion tectonics
%K Northern Chile
%U http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062012000200004