Primary Investigator: Jose Miguel Cembrano, PONTIFICIA UNIVERSIDAD CATÓLICA DE CHILE
Coinvestigator: W. Ashley Griffith
In this project, we plan to address the tectono-magmatic significance of NW and NE-striking,long-lived basement fault structures, through a combination of field geology, geophysics and numerical modeling. We will tackle the problem by selecting two outstanding case studies of in the Andes of Central Chile: The Tatara-San Pedro-Pellado volcanic complex- Laguna del Maule volcanic field Alignment (TSPP) and the Cortaderas-Chillán lineament (CChL). Our working hypothesis is that WNW and ENE-striking structures correspond to long-lived fault zones that play a fundamental tectono-magmatic role in Andean evolution. They have accommodated part of the upper plate deformation arising from the ~ ENE-WNWtrending shortening and –at the same time- they have provided episodic pathways for magma and hydrothermal fluid transport in the lithosphere. Furthermore, we speculate that because WNW-striking fault zones are severely misoriented with respect to the prevailing stress field, they reactivate as sinistralreverse faults under nearly lithostatic fluid pressures. ENE-striking faults, in turn, have a dextral-normal kinematics and do not require supra-lithostatic fluid pressures to reactivate. The expected outcome of this project is a robust tectono-magmatic model that can account for thenature, timing and tectono-magmatic role of Andean transverse structures. We hope that these ideas can shed light on exploration strategies of ore deposit and geothermal resources in the Andes and other mountain belts.