Compressional Pliocene and compressional-transpressional Pliocene states of stress, southern Chilean Andes (38-42 degrees 30 ' S).

Miocene-Pliocene and Quaternary intrusive rocks and sedimentary deposits fr om the Central Depression and the Main Cordillera, between 38 and 42 degree s 30'S, have been affected by local and regional brittle deformation. Micro fault geometry and kinematic analysis along with calculation of deviatoric tensors allowed to determine regional-scale states of stress. Two tectonic events were identified. A Pliocene event, prior to the Quaternary, affects the entire zone of study, and is characterized by a maximum compressional s tress sigma(1), roughly oriented in an E-W direction. A Pleistocene event c orresponds to an overall deformation partitioned into two coeval distinctiv e states of stress: a compressional stress sigma(1), oriented in a N-S to N NE-SSW direction in the fore are zone, and a dextral transpressional state of stress with sigma(1) striking NE-SW, in the intra-arc zone.