Abstract

MARTINEZ, Andrea L; MONTENEGRO, Teresita  and  HIGA, Luciana. Geología del basamento del borde nor-oriental del batolito Las Chacras-Piedras Coloradas, Libertador General San Martín, provincia de San Luis. Rev. Asoc. Geol. Argent. [online]. 2015, vol.72, n.4, pp.563-574. ISSN 0004-4822.

The studied area is located in the northeast of the Sierra de San Luis, and southwest of the Libertador General San Martín town, near Los Avestruces tungsten deposit and east of the Las Chacras-Piedras Coloradas Batholith. Even though this sector belongs to the Conlara Metamorphic Complex, it presents different lithological and structural features between eastern and western areas. In the eastern area, medium grain quartz, biotite and calc-silicate schists, and gneisses outcrop. Granites, pegmatites -frequently with boudinage structures-, and aplites, are conformably hosted in the metamorphic sequence. Scheelite and wolframite veins with associated lamprophyres are common in this area. The western area, however, consists of an assemblage of biotite and tourmaline schists, phyllites and meta-sandstones. The same types of intrusive rocks outcrop in this area, but the pegmatites are intensely folded. The tungsten veins are scarce. Granitoid rocks in both sectors show similar geochemical features to other Famatinian granitoids of the sierra. While both sectors reach amphibolite facies, structure directions are different. In the eastern area structures show predominant NE direction while the western area shows preferentially NNW orientation of the structures. Consequently, the eastern area can be linked with the gneisses and migmatites of the Conlara Metamorphic Complex while the western area outcrops resembles to those at the North of the Sierra, which were grouped under the name of Metamorfitas San Martín y Las Higueras according to previous authors.

Keywords : San Luis Range; Igneous-metamorphic basement; Conlara Metamorphic Complex.

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