Abstract

SRUOGA, Patricia et al. Structural and lithofacies analyses of the Bahía Laura Complex in the El Dorado-Montserrat Area, province of Santa Cruz. Rev. Asoc. Geol. Argent. [online]. 2008, vol.63, n.4, pp.653-664. ISSN 0004-4822.

The Dorado-Monserrat area is located in the southeastern edge of the Deseado region, 110 km far from Puerto San Julián. It has an economic interest due to the Au-Ag-Ba epithermal vein system and also, the area is suitable for carrying out lithological and structural studies of the Bahía Laura Volcanic Complex (BLVC), of Middle to Late Jurassic age. Four lithofacies have been recognized (intermediate lavas/dikes, piro-epiclastics, welded ignimbrites, rhyolitic lavas/dikes), with special emphasis on near-vent facies. In addition, several normal faults, trending ENE (N 75°) and NNW, were identified. They are closely associated to the extensional regime which strongly controlled the Bahía Laura Volcanic Complex emplacement during the rift evolution. The study area is proposed as a recurrent eruptive centre, both during efusive and explosive activity, controlled by main en-échèlon ENE trending normal faults. Hypothetic trapdoor type calderas should have generated during large-volume ignimbrites emplacement.

Keywords : Lithofacies; Structure; Volcanism; Jurassic; Santa Cruz.

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