Kinematic Evolution Model for the Growth of a Passive Roof Duplex in the Marañón Fold and Thrust Belt – Ojo de Consuzo Duplex, Ancash, Peru

Abstract

Recent studies in mineral deposit exploration have enhanced our understanding of the geometry of the Marañón Fold and Thrust Belt (MFTB) in central and northern Peru’s Andes, where both thin-skinned and thick-skinned deformation are present, directly related to the evolution and stress response of older structures. However, many of these studies are based on outdated geological information. This study highlights a passive roof duplex in the inner zone of the MFTB in northern Ancash province, Peru, based on updated national geological mapping. The concept of a wedge stacking large rock fragments balanced by back thrusts in the superficial layers at the front of the wedge is a concept that has been little studied in the MFTB. This study demonstrates how with a simple structural analysis methodology, satellite image analysis, and the interpretation of a structural section, such types of structures can be determined, especially at the level of exposure that will be presented below. The analysis of this structure shows us an antiformal stacking and indicates how the outcrops of the Upper Jurassic, mapped only in this area, have influenced the thin-skinned deformation in this part of the MFTB and how this shortening affects the tectonic transport of the entire basin.