3D reconstruction of syntectonic strata deposited during the inversion of salt-related structures: Insights from the llert syncline (south-central pyrenees)

Abstract

The Llert syncline is located in the South-central Pyrenees, between the eastern termination of the E-W trending Cotiella Basin and the north-western limb of the N-S trending Turbón-Serrado fold system. The Cotiella Basin is an inverted upper Coniacian-lower Santonian salt-floored post-rift extensional basin developed along the northern Iberian rift system. The Turbón-Serrado fold system consists of upper Santonian–Maastrichtian contractional saltcored anticlines developed above an inverted transfer zone of the Pyrenean rift system. Based on field observations, we have conducted a 3D reconstruction of the Llert syncline in order to further constrain the transition between these oblique salt-related structures. Our results suggest that the evolution of the Llert syncline was mainly controlled by tectonic shortening related to the positive inversion of the Cotiella Basin, synchronously to the growth of the Turbón-Serrado detachment anticline. This structure was also conditioned by the pre-compressional structural framework of the Pyrenean rift system. Our contribution provides new insight into the geometric and kinematic relationships of structures developed during the inversion of passive margins involving salt.