Olistostromes and the onset of subduction

Abstract

Olistostromes found in a number of major fold belts are of an age comparable with the start of underthrusting as indicated by attendant arc-related volcanism. They occur at the inner edge of inferred accretionary wedges, and are commonly associated with contemporaneous basaltic rocks. These olistostromes may result from disruption of the crust during lithosphere fracturing at the commencement of subduction. Components of the olistostromes provide evidence concerning the site of initial underthrusting.