Geometry and kinematics of an antiformal stack deduced from brittle structures. Example of the Internal Betic Zone in the Sierra Espuña (province of Murcia, Spain)

Abstract

In this work, we present a detailed analysis of brittle and brittle–ductile structures related to the contacts of a stack of tectonic units cropping out in the Sierra Espuña (Betic Cordillera, southern Spain). These data show two superposition stages with opposing transport directions: first, a top-to-the-north (according to current coordinates) stage (Oligocene in age), and a second stage from the Middle Oligocene–Aquitanian, with a top-to-the-north sense of transport. In the Burdigalian, the Internal Betic Zone units of the Sierra Espuña sector could rotate near 180° because of the oblique collision against the External Zones, and therefore the previous stacking directions went in the contrary direction with respect to that measured nowadays. The reconstruction of movements shows that the Malaguide Complex was situated to the south of the Alpujarride prior to the Alpine tectonics, which is in good agreement with previous palaeogeographic reconstructions.