The orogenesis in the andean system of colombia

Abstract

The structural provinces of Colombia are briefly outlined and the tectonic and magmatic events discussed in historical order. The Paleozoic is considered as an era of compressional movements which culminated in the Caledonian (and Variscean?) orogeny. They caused a retreat of the sea to the west Andean area and the temporal consolidation of the east Andean province. In the east Andean province the Early Mesozoic is a time of tensional fault movements and extrusion of alkaline magmas. This break-down was followed by an advance of the sea which, in Middle Cretaceous time, covered the same geographical area as during the Early Paleozoic. The west Andean province remained ocean floor and was successively covered by an increasing amount of toleitic basalt flows. At the end of the Cretaceous, compressional forces set in again and the sea retreated from the east Andean province. In the course of several Cenozoic tectonic phases the Cordilleras moved upward, while the depressions between them moved downward and were filled with mainly terrestrial deposits of up to 10,000 m in thickness. The final uplift of the Colombian Andes to their present height (up to 5,800 m) took place after Early Pleistocene time.