RIFTS AT HIGH ANGLES TO OROGENIC BELTS: TESTS FOR THEIR ORIGIN AND THE UPPER RHINE GRABEN AS AN EXAMPLE.

Abstract

Rift valleys striking at high angles to orogenic belts are of two main kinds: those originating at ocean opening (aulacogens) and those originating at collision (impactogens). The authors consider differences between the geological evolution of the two kinds of rifts that can be helpful in distinguishing between them. They review the Permian to Recent evolution of the Upper Rhine Graben as an example. There is little evidence to support the idea that there was active rifting in the Rhine Graben in Late Triassic times contemporary with the opening of the Alpine Tethys. Refs.