Unraveling 470 m.y. of shortening in the Central Andes and documentation of Type 0 superposed folding

Abstract

In the Famatina Ranges, Central Andes of western Argentina, 470 m.y. of protracted shortening is recorded through episodic coaxial-coplanar fold amplification. Ordovician anticlines within the east-vergent thrust belt were refolded and tightened during later Paleozoic and Cenozoic shortening. Folding episodes are recorded in four major unconformities that can be measured on both flanks of one of these map-scale anticlines. Superposed folding (Type 0), interpreted from mapping and bedding plots, shows similar axial orientation in older and younger rocks throughout the different stratigraphic layers. Of the shortening, 30% is pre-Cenozoic and allows the recording of episodic deformation during continuous plate convergence at the Gondwana–South American margin.