Large-scale structure of an Intraplate Fold-and-Thrust Belt: The Iberian Chain.

Abstract

The Iberian Chain is an intraplate fold-and-thrust belt developed during the late Eocene to Miocene because of the contractional inversion of the Iberian Mesozoic Basins. Its dominant trend is NW-SE, but E-W-, NE-SW- and N-S-trending structures are also present inside it. Its NE and SW boundaries are major thrusts: The North Iberian Thrust and the Serranía de Cuenca Thrust. The thrust-sheet on top of these thrusts, display two big anticlinoriums, separated by the big Almazán Synclinorium. They are interpreted as major fault-bend folds developed over the ramp and flat geometry of the two major thrusts. The level of erosion is low in most of its extent, so there is a small difference between the tectonic and the topographic reliefs. Hence, a low dip is needed for the major thrusts. A model section is presented which fits a cross-section thru the chain. A total displacement of 60km of the thrust-sheet is needed to fit the cross-section geometry, and the sole thrust is located at a depth of 10km.