Structural Evolution and Coupled Kinematic-Thermal Modeling of the Upper Magdalena Basin in the Vicinity of the Garzon Massif, Colombia

F. Roure¹, J. L. Faure², B Colletta², C Macellari³, and M Osorio^4
1 IFP, Rueil-Malmaison, France
² IFP,
³ Hocol, Bogota, Colombia
⁴ Hocol,

The Upper Magdalena constitutes an intramountain basin, characterized by a succession of horsts and grabens inherited from Jurassic rifting episodes. Post-Jurassic sedimentation records subsequent Cretaceous thermal subsidence and Paleogene flexural subsidence in the foreland of the Central Cordillera, and Neogene transpressional reactivation and inversion of the Jurassic grabens during Andean tectonics, coeval with the thrust emplacement of the Eastern Cordillera. Surface and subsurface data including regional reflection seismic profiles and wells have been used here to constrain four structural sections across the Suaza Graben, between the Tarqui Horst in the west and the Garzon west-verging basement overthrust in the east. Cross-section balancing techniques have been used to restore the sections in their pre-orogenic configuration, the later being ultimately used to perform a coupled forward kinematic and petroleum modelling with Thrustpack. Results of the modelling demonstrate the strong control of the Garzon basement overthrust on the timing of the petroleum systems in the underthrust grabens. Surprisingly, the maturity ranks computed along the two profiles located beneath the Garzon overthrust are slightly less than in coeval portions of the Suaza Graben which are located farther south and farther north. Therefore, it is assumed that high conductivity in the autochthonous basement drives more heat to the source rocks in the vicinity of the Tarqui Horst, and conversely, high conductivity in the basement allochthon is responsible for faster cooling of the sediments below the Garzon overthrust.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005