The influence of orogenic collision inheritance on rifted margin architecture: Insights from comparing numerical experiments to the Mid-Norwegian margin

Abstract

Most rifts and rifted margins around the world developed on former orogens. This implies that the pre-rift lithospheric configuration is heterogeneous in most cases. Here we investigate how collision inheritance in the form of inherited weak thrusts, long-term thermal weakening, compositional changes, and orogenic collapse, could have played into the spatio-temporal evolution and final architecture of rifted margins. We present interpretations of dynamic numerical experiments, including constraints representative of the North Atlantic Mid-Norwegian rift system phases of continental collision, orogenic collapse, and extension, and compare these to interpretations of seismic reflection profiles. The experiments form rifted margins characterized by basement structures and sedimentary geometries very similar to the Møre and Vøring rifted margins - with onshore collapse-related basins, extensively deformed continental crust with detachments, shear zones, core complexes, rotated thrusts and an offshore succession of distinct structural domains (proximal, necking, hyperextension, exhumation, and outer). Although extensional models developed on homogeneous lithosphere are a good approximation of rifted margin architecture, our results suggest that models that consider pre-rift orogenic inheritance tend to reproduce more accurately the geometries observed in our natural example.

Topics & Concepts