VERGENCIAS OPUESTAS CUATERNARIAS EN EL AREA DE ACEQUION, PRECORDILLERA DE SAN JUAN (ARGENTINA)

LAURA P. PERUCCA; FRANCK ALBERT AUDEMARD; A. PANTANO; HORACIO NICOLÁS VARGAS; CARLOS ROBERTO AVILA; MARÍA ROMINA ONORATO

Revista de la Sociedad Geológica de España

Universidad de Salamanca. Facultad de Ciencias

Lugar: Salamanca; Año: 2012 vol. 25 p. 5 - 15

0214-2708

Some new evidences of Quaternary faulting between two structural systems, characterized by reverse faults with regional N-S strike and opposite vergences, occur at the depression placed between Sierra del Tontal - cordón Santa Clara and Sierra de Pedernal-Los Pozos (Precordillera of San Juan, Argentina).The Pleistocene-Holocene alluvial fill of this valley is crosscut by north-south trending thrust faults, arranged in two major trends of opposite vergency: a thin-skinned east verging one, very similar to the Precordillera Central style of deformation, and a second basement-involved west-verging one, resemblingthe structural style of the Precordillera Oriental, fact indicating the presence of a thick-skinned triangle zone. Most of the Pleistocene and even early Holocene displacement would have been concentrated by two Andean type thrusting (Acequión and Cerro La Chilca faults) and associated minor faults, beingthe triangular zone on the western flank of Sierra de Pedernal-Los Pozos.Finally, deformation structures recognized in the region would indicate the persistence of a compressive regime during late Pleistocene- early Holocene, which would be associated with thrust faults verging to the east and west. These faults continue to raise the mountain ranges located east and westof the depression, as indicate the elevated and folded Holocene lake levels located on the western flank of the Sierra de Los Pozos.