MODELS FOR RELATIVE MOTION OF CRUSTAL BLOCKS WITHIN THE CARPATHIAN REGION, BASED ON RESTORATIONS OF THE OUTER CARPATHIAN THRUST SHEETS

Details of the Oligocene-present-day motion of the Adriatic block with respect to Europe can be determined by palinspastic restorations of t he outer Carpathians thrust sheets. The arcuate nature of the Carpathi ans poses problems for simple restorations of sections because they cr eate converging restoration paths which require large amounts of strik e-parallel extension (40-50%). Such large amounts of extension are not seen on maps or in the field. A combination of thrust transport direc tions changing with lime between and within thrust sheets and divergen t transport directions helps minimise the arc-parallel extension neces sary (18-25%). The Pannonian basin can be treated either as an area do minated by strike-slip motion (rigid block movements) or as an area of back are extension. Tile differences in restoration geometry produced by these two scenarios help to indicate which of the two mechanisms w as dominant. The consequences of the rigid block restoration indicate the model is inappropriate because it requires approximately 20 degree s clockwise rotation of the Adriatic block during the late Tertiary. I t also indicates at least 300 km strike-slip motion distributed among the late Tertiary faults of the Dinaride-Balkanide and Hellenide Mount ain belts. The back are extension model alleviates the the 20 degrees clockwise rotation of the Adriatic block and requires about 200 km dis tributed strike-slip motion in Yugoslavia and Bulgaria.