Mechanisms of accretion and subsequent thickening in the Barbados Ridge accretionary complex: balanced cross sections across the wedge toe

Abstract

Detailed analysis of ODP Leg 110 cores provides evidence for a complex structural evolution of the frontal thrust system of the Barbados Ridge accretionary wedge. Thrust faulting and back rotation are the dominant thickening mechanisms within 5km of the toe of the wedge. Folding and duplex formation are only secondary thickening processes at this point. The overall progression in structural style across the accretionary wedge is discussed and reflects the need for continuous shape adjustments to maintain a stable critical taper during progressive accretion. Erosion of material from the slope of the wedge at Sites 673 and 674 may have had an important affect on the structural development of the wedge. It is important to note that erosion becomes significant in the region of the wedge where underplating and out-of-sequence thrusting is proposed to have occurred. -from Authors