THE INTERPLAY BETWEEN FLUIDS, FOLDS AND THRUSTS DURING THE DEFORMATION OF A SEDIMENTARY SUCCESSION

In this paper, field evidence is presented to support the idea that fl uid pressures in excess of lithostatic pressure were operating during the initiation and reactivation of large thrusts and folds in the Wenl ock shales of Llangollen, North Wales. It is also argued that as major thrusts are reactivated and as major folds amplify into finite struct ures they in turn exert an influence on the subsequent migration and c oncentration of fluids within the deforming sedimentary succession.