Lateral and temporal variations in thrust belt behaviour in a low convergence retrowedge, north Pyrenees.

The Pyrenees is a collisional orogen built by inversion of an immature rift system during convergence of the Iberian and European plates from Late Cretaceous to late Cenozoic. The full mountain belt consists of the pro-wedge and foreland of the southern Pyrenees and the retro-wedge and foreland of the northern Pyrenees, where the inverted lower Cretaceous rift system is mainly preserved. Due to low overall convergence and absence of oceanic subduction, this immature orogen preserves one of the best geological records of early orogenesis, the transition from early convergence to main collision and the transition from collision to post-convergence. During these transitional periods major changes in orogen behavior reflect evolving lithospheric processes and tectonic drivers. These records are best preserved in the North Pyrenean Zone (NPZ), the retrowedge thrust belt and its adjacent syn-orogenic basin. This paper reviews along strike variations in structural and stratigraphic characteristics of the NPZ and adjacent basin evolution and explores the changing role in space and time of rheological, thermal and structural Inheritance and local and plate scale drivers.