Interpretación geodinámica de la vertiente centro-occidental surpirenaica (cuencas de Jaca-Tremp)

Abstract

A system of imbricated thrusts (piggy-back sequence), coeval with the sedimentary filling of the Jaca and Tremp basins, was generated during Eocene and Oligocene. The Eocene sedimentation was conditioned by ramp anticlines, thus creating syntectonic slope facies on the smooth or rear slope of each thrust (Burgui marls and limes tones). Separating these ramp anticlines are several troughs containing different turbiditic systems. Within these systems and channelized along the troughs, assembla,ges of carbonate megabeds are intercalated. These assemblages migrated southwards, while each individual megabed within every assemblage shifted eastwards. This arrangement reflects the general thrust sheets movements as they were emplaced earlier at the western pan of the Jaca basin, being progressively displaced towards South and East. The carbonate material that compose the megabeds would source from a northern Eocene platform, located on the active basin margin, as well as from erosion on the ramp anticlines simultaneously created.
The imbricated thrust system affecting the cover is genetically related to and overlain a big duplex system developed on the basement. The latter dips NW, being of "hinterland dipping" type and has its root or "branch line" located on an intrapaleozoic fault within the axial zone. The tectonic configuration was generated by an NNW-SSE compression, probably due to the dextral relative movement between the Iberian and European plates.