REACTIVACIÓN DE ESTRUCTURAS EN EL ÁREA LOS COLORADOS. LÍMITE OCCIDENTAL DE LA CORDILLERA ORIENTAL JUJEÑA

EMILIO BARRABINO; RAÚL SEGGIARO; EDUARDO GALLARDO

Tucumán

Congreso; XX Congreso Geológico Argentino; 2017

Asociación Geológica Argentina

REACTIVATION OF STRUCTURES IN LOS COLORADOS AREA. WESTERN BOUNDARYOF THE JUJUY EASTERN CORDILLERAThe región betwen Los colorados and Lipán ranges, located on the western border of the Eastern Cordillera with the Puna, shows a structural setting generated by two west-vergent thrusts that record evidences of reactivations of paleozoic and cretaceous faults. An asymmetric syncline with NNE steering axis is development between these two thrusts. In its western flank ordovician deposits of the Santa Victoria Group are exposed followed in conformity by silurian-devonic strata. Towards the core of the synclinal the fill sequences of the rift basin Salta Group unconformably overlies with low angle. Los Colorados thrust limits the western flank of the syncline and displaces Ordovician strata over the Pirgua Subgroup. The palinspastic reconstruction of this thrust shows a pre-Cretaceous block with the Paleozoic units inclined to the east. The eastern flank is truncated by the Lipán thrust juxtaposes the basement and Cambro-Ordovician strata with the Pirgua Subgroup. When performing the palinspatic reconstruction to the roof of the Salta Group, the existence of a normal Cretaceous fault inclined to the west at the foot of the western slope of the mountain of Lipán is reflected. When this reconstruction is carried to the floor of the Cretaceous, the basement and the cambro-ordovician units are in contact with the silurian-devonic strata revealing a strong anisotropy of the substrate where the fracture and the displacement of blocks would have occurred during the construction of the Cretaceous rift.