Determinación de direcciones principales de esfuerzos neotectónicos mediante el análisis del maclado mecánico de la calcita

Abstract

Pleistocene karstic deposits developed into Upper Cretaceous limestones of the Prebetic zone, in the boundary region between the Iberian and Betic chains, were sampled in order to investigate the calcite e-twin occurrence in these modern sediments. Amazingly, sparry calcite grains from the karstic coating have mechanical twins, and they are very abundant in these grains close to recent faults (twin density of 5.7 twins/mm). Analysis of calcite e-twining by inverse methods reveal that the region has undergone an extensional regime with maximum shortening direction NE-SW. Similar results were obtained from fault population analysis. Which points out that calcite e-twin analysis are useful to establish the neotectonic principal stresses orientation in this region. The e-twin analysis techniques based on strain determinations also yield good results.