Geology of cerro Los Guanacos area, Calamuchita department, Córdoba province
Geologically, the area of cerro Los Guanacos belongs to the Sierras de Córdoba basement and consists of an upper Proterozoic-Eopalaeozoic sequence of serpentinites, amphibolites, gneises, schists, marbles and metaquarzites, with mineralogical assemblages that indicate medium-grade metamorphism (amph...
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00044822_v57_n1_p55_GonzalezChiozza |
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| Sumario: | Geologically, the area of cerro Los Guanacos belongs to the Sierras de Córdoba basement and consists of an upper Proterozoic-Eopalaeozoic sequence of serpentinites, amphibolites, gneises, schists, marbles and metaquarzites, with mineralogical assemblages that indicate medium-grade metamorphism (amphibolite facies), equivalent to that observed regionally. Petrological, geochemical and structural studies were used to define the protoliths of the sequence. The base of the sequence is marked by the Los Guanacos ultrabasic body, a serpentinized ophiolitic fragment originally composed of mantle-crust transitional peridotites with associated basic sills. These rocks are overlain by metamorphites generated from marine pelitic sediments with intercalations of tabular bodies of limestone, basalt and silicic layers. Similarities in the rare earth element content of the three igneous lithotypes of the sequence (peridotites, basites from sills and basalts), suggest a comagmatic relationship between them. Structurally, the area is dominated by a synformal anticlinal fold, which hosts the Los Guanacos chromite-bearing ultramafic body in its core. Also remarkable is the presence, in the base of the ultramafic body, of an amphibolitic metamorphic sole that is associated with a shear zone, and defines a tectonic contact between the ultrabasites and migmatic gneises. |
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