SANTANDER MASSIF

Determine the importance of the tectonic control in the exhumation and uplift of Santander Massif from Eocene to late Miocene; and assess if erosion (unloading) also played an important role in the history of exhumation and uplifting of Santander Massif during this time.

A compilation of published and new apatite and zircon fission-track and (U-Th)/He cooling ages along a transect between the Bucaramanga and the Guaicáramo faults is presented here to support the interpretation of Pre-Pleistocene episodic exhumation and deformation during the evolution of the central part of the Santander Massif's. The Pamplona Wedge controls the structural evolution of the central part of the Santander Massif producing a set of north to south trending transpressional faults and curved oblique faults with a dextral (NE-SW) and sinistral (NW-SE) slip component in a regional framework developed by indentation tectonics.

The whole database points to three tectonic events: (i) exhumation during the Late Cretaceous, (ii) exhumation and uplifting of the western flank of the Santander Massif from Eocene to early Miocene times, and (iii) exhumation and uplifting associated to increasing deformation toward the central part of the Santander Massif from late Miocene to Recent times. The first phase was associated with shortening and reactivation of intraplate structures as consequence of the interaction of the Nazca, Caribbean Plate and South America Plates. The second phase was related to tectonic activity of the Bucaramanga Fault and structures as the Suratá Fault, in turn caused by the onset and final closure of the collision of the Panamá-Chocó Block; this phase was characterized by fast erosion with isostatic response of the massif. The third phase was related to westward motion of the Pamplona Wedge.

Our and published thermochronological data agree with quantitative geomorphological and structural data suggesting that the current geomorphology reflects the tectonic control from the late Miocene to the Recent, associated with the most recent phase of exhumation, surface uplift and rejuvenation of deformation toward central part of the Santander Massif.