Abstract

The complex tectonic evolution of northwestern South America is recorded by a variety of deformed, onland basins ranging in age from Paleozoic to recent. We integrate the Mesozoic to recent structural geology and basinal history of the 12,000 km², intermontane Cesar-Rancheria Basin (CRB) in northern Colombia to reconstruct the tectonic history of the basin and tectonic controls on its sedimentation, subsidence history, and petroleum systems. Methods and data used for this study include (1) interpretations of crustal structure using gravity and magnetic modeling; (2) subsurface mapping of key horizons using 3500 km (2175 mi) of two-dimensional (2-D) seismic reflection data tied to 16 wells; (3) construction of serial structural cross sections, which are balanced to the level of Late Cretaceous sedimentary rocks; and (4) construction of burial history graphs and development of a 2-D basin model showing predicted oil and gas windows. Basement-involved southeast-dipping reverse faults expose Jurassic to early Cretaceous rocks in the CRB and Paleozoic rocks in the Perija range (PR) east of the CRB. About 10% of shortening across the CRB is a consequence of motion along these faults driven by discrete interactions between the Caribbean and South America plates. Two major periods of NW-SE crustal, interplate shortening are identified: (1) an early–middle Eocene, west-to-east shortening event that produced east-dipping Cretaceous and Paleocene strata beneath a major unconformity that increases in erosional hiatus from east to west across the study area; this shortening and overlying unconformity is related to the collision of the Great Arc of the Caribbean with the northwestern continental margin of the South American plate; and (2) a late Miocene–Pliocene, west-to-east shortening event with major exhumation of the eastern CRB where faulting of recent sedimentary deposits are related to the collision between the Panama Arc and northwestern South America. The west-to-east migration of deformation during the Cenozoic controlled by the west-to-east, diachronous collision between the Great Arc of the Caribbean and northern South America also led the present-day distribution of preserved depocenters with a major thickness of the Paleocene-early Eocene section to the east of the study area, and a major Miocene depocenter to the west.