Structural control and tectonic environment of the Cenozoic giant Kadjaran porphyry Cu-Mo and epithermal system, southern Armenia, Lesser Caucasus

In this contribution, we focus on the Oligocene to Miocene structural evolution of the giant Kadjaran porphyry Cu-Mo deposit and its epithermal overprint. This evolution was controlled by long-lived regional faults during the Cenozoic tectonic and magmatic evolution of the Meghri-Ordubad composite pluton located in the southernmost Lesser Caucasus. We discuss the ore-bearing fracture network characteristics related with the deposit-scale ore-controlling structures in the frame of regional strike-slip faults. Stereonets summarizing the orientations of different generations of mineralized veins allow us to constrain the favorable fracture network environment for ore-formation at the giant Kadjaran deposit. During the middle- late Oligocene, NNE-oriented shortening created the major similar to N-S- and NE-oriented steeply dipping ore-controlling deposit-scale faults under dextral strike-slip tectonics. The gently to moderately dipping NE-, similar to N-S- and similar to E-W-oriented fracture networks along the steeply dipping deposit-scale faults were the most important structural control for the emplacement of the main porphyry stockwork mineralization. These deposit-scale ore-controlling faults were reactivated during the early Miocene under WNW-oriented shortening and NNE-oriented extension. The progressive anticlockwise rotation of paleostress orientations from middle- late Oligocene to early Miocene was linked to reorganization of tectonic plates during Arabia-Eurasia collision.