Original paper

Local inversion in rifts triggered by micro-plate rotation

Kahn, Daniel; Lindenfeld, Michael; Rumpke, Georg; Aanyu, Kevin

Abstract

Continental rifts are large extension related structures that form in the crust of the Earth. Even though these systems form during extension we show in this contribution that local block rotations can lead to compressional features and thus inversion within the rift. An extreme example of such an inversion is the Rwenzori mountain range, a 5000m high basement block that lies within the western part of the East African rift system (Fig. I). We show with a numerical model how such a basement block can be captured within the rift and how it rotates during progressive rift opening to produce local inversion structures and active normal faults that strike parallel to the current opening vectors of the rift. We finally compare these results with fault patterns in the field, fault plane solutions from active fault systems around the Rwenzori block and recent GPS measurements of plate movement vectors.