Fracture pattern analysis as a tool for constraining the interaction between regional and diapir-related stress fields: Poza de la Sal Diapir (Basque Pyrenees, Spain)

Abstract

AbstractDuring diapir evolution the local stress field results from the interaction between diapir-related and remote ‘regional’ stress fields. The fracture pattern hosted in the overburden can register this evolving interaction, providing significant insights for the unravelling of the diapir kinematics. In this work we present the example of the Poza de la Sal Diapir, which is a salt diapir that pierces the synorogenic deposits of the Basque Pyrenees. The integrated analysis of mesostructural data, which includes field-collected faults, joints and fracture traces digitalized on high-resolution orthophotos, allowed us to establish an evolutionary model for the stress field around diapirs. The presented data support the idea that, during diapir evolution, stress fields evolve from mostly regional-related to mostly diapir-related. Contrasting with other geological data (seismic data, geological map and cross-section), we observe that different methods provide complementary information, coherent with the proposed evolutionary model of the Poza de la Sal Diapir.