INVERSION TECTONICS OF THE VARISCAN FORELAND OF THE BRITISH-ISLES

Late Westphalian inversion structures on the Variscan foreland display wide variations in orientation that are the product of the underlying basement grain. The orientation of the major basement lineaments in r elation to the direction of maximum shortening also determined the sev erity of deformation of the inverted basins. NE-SW-trending faults wer e oriented roughly perpendicular to the NW-SE to NNW-SSE direction of maximum shortening determined from thrust transport directions in the Variscan orogen to the south. As a consequence, NE-SW-trending basins in the Variscan foreland have been strongly inverted, the Silesian pos t-rift fill has commonly been expelled from the basins and the syn-rif t sediments have been deformed by chevron folds (Dublin and Bowland Ba sins). In contrast, the N-S- and NW-SE-trending faults were oriented m ore obliquely to the direction of maximum shortening and, as a consequ ence, display a significant component of oblique slip. This oblique sl ip component is manifested as en-echelon periclines and flower structu res. In general, the N-S- and NW-SE-trending basins were less strongly inverted and the Silesian post-rift fill has been retained.