Paleogene kinematics of the central Catalan Coastal Ranges: temporal constraints from magneto-chronology and provenance analysis in synorogenic deposits in the SE margin of the Ebro Basin (NE Spain)

Abstract

The precise determination of the tectonic deformation timing such as thrust emplacement has always been a challenge for understanding the evolution of fold-and-thrust belts. In the Catalan Coastal Ranges, this issue has traditionally been addressed through the mapping and the analysis of the syn-tectonic successions preserved in the SE margin of the Ebro Basin. However, the age of the Paleogene contractional structures located towards the hinterland and responsible of the inversion and uplift of the inherited Mesozoic structure remained uncertain due to the lack of preserved syn-kinematic strata in these areas. With the aim of better understand the contractional evolution of the area during the Paleogene, this work presents a tectono-stratigraphic analysis approach that combines structural reconstructions, provenance analysis and magnetostratigraphic dating in well-exposed synorogenic sediments in the central SE margin of the Ebro Basin. The results of the study allow to establish the precise age of the main contractional structures present in the central Catalan Coastal Ranges. The combined analysis has revealed that: 1) the inversion of the Montmell-Vallès Faults System started in the Bartonian and continued up to the late Priabonian, and 2) the emplacement of the Gaià-El Camp Thrust and the formation of the Cabra-Carme Anticline took place from early to late Priabonian and was the responsible of the sudden increased of the sedimentation rates. A later decrease of the sedimentation rates during late Priabonian (chron C15n) has been interpreted as the prelude of the end of the Paleogene compressional phase in the area.