Stress evolution at the horsetail end of a major strike-slip fault: Tectonic controls on a large porphyry, South Cotabato, Philippines

Category Tectonic & Seismotectonic
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Aurelio, Mario Juan A.
Holding Date 11 October 2008

Tensor solutions calculated from a microtectonic study of the Tampakan area in south Cotabato, Philippines, indicate rotating stress orientations in the past few million years. The area, believed to be straddling the SW flank of an eroded stratovolcano, is traversed by a fault system characterized by an evolving left-lateral shear pair controlled by southern horsetail branches of the Cotabato Fault Zone. This stress regime evolution provides insights to help explain seemingly anomalous fault orientations which are theoretically inconsistent with classical wrench fault tectonics, as well as in understanding the spatial and temporal relationships between mineral concentrations and geologic structures.