SYNTECTONIC BURIAL AND POSTTECTONIC EXHUMATION OF THE SOUTHERN PYRENEES FORELAND FOLD-THRUST BELT

In the Oligocene to earliest Miocene the entire southern Pyrenean fore land fold and thrust belt was backfilled and buried in up to 3 km of s yntectonic continental conglomerates from the range's own erosional de bris. Then, starting in the mid to late Miocene, the Pyrenees were exh umed by erosional excavation to their present relief. A model is propo sed for this unusual development whereby late Eocene-Oligocene tectoni c uplift of the margins of the Ebro basin raised local base level and blocked normal dispersal of erosional debris to adjacent oceans, thus causing the basin to fill then backfill northwards across the entire s outhern flank of the Pyrenees. Subsequent Miocene rifting of the Catal an Mediterranean margin, and the Messinian salinity crisis, lowered ba se level allowing the Ebro River to cut headward, capture the Ebro bas in, and re-excavate the Pyrenees.