Mesozoic Structures between Volcan Maipo and Cerro Campanario in the Cordillera Principal, Mendoza, Argentina

NULLO FE; PROSERPIO CA; HALLER MJ

Santiago

Simposio; Symposium on Geology of the Andes and its Relation to Hydrocarbon and Mineral Resources; 1985

Circumpacific Council for Energy and Mineral Resources

A thick Mesozoic sedimentary sequence of marine and continental origin is recognized in the southern segment of the Cordillera Principal. On a basement of Permo-Triassic siliceous volcanics, Lias-Early Cretaceous marine sediments developed in an important basin represented a lowstand during the Kimmeridgian. From the Neocomian onwards, thick clastic sediments were deposited in elongated mountain basins. Volcanic activity started toward the end the Cretaceous, related to the active continental margin of the American plate. The main structural features of this segment of the Andes are tilted folds related to southerly trending thrusts with typical east vergency. The increasing instability of the basin, which started in the Early Cretaceous, gave as a result the transverse shortening of the basin, its uplift and finally the development .of intermountain basins during the Senonian. The present landscape of the Cordillera is the result of reactivation of Mesozoic tectonic lineaments during Tertiary times. Guidelines for the prospection of potential economic resources in Southern Mendoza are discussed, based on the structural evolution of the area. Stratabound barite deposits are related to regressive stages of the Mesozoic depositional sequence. This region is also an important oil and gas producing area. Uranium ore deposits are associated to Late Senonian continental sequences.