Aplicación del análisis de paleoesfuerzos a regiones plegadas: la compresión terciaria en el sector de Cariñena-Belchite (borde norte de la Cordillera Ibérica)

Abstract

Palaeostress analysis from brittle mesostructures (mainly faults and stylolytes) in the norther border of the Iberian Chain (Cariñena-Belchite area) shows the existence of several compressional stress states, with σ₁, axes oriented NNE-SSW, NW-SE, ESE-WSW. NNE compression direction is consistent with the main shortening direction, responsible for the formation of most macro-structures. Some NE and NW compression directions are due to deflection of the principal compression by larger reverse faults and folds. The deflected compression axes are then perpendicular to macro-structures. ESE compression is early with respect to the main compressional stage, and corresponds either to a intra-mesozoic compression or an Early Tertiary shortening stage. The results obtained in this study indicate that palaeostress analysis in fold-and-thrust areas, even when deformation is not very strong (in this area the total shortening is less than 15 %) must be carefully interpreted, taking into account deflections of the stress fields due to larger macro-structures.