its eastward migration from the Pacific region. Late Cretaceous After rifting, the northern edge of the South American plate developed into a passive margin with the Proto-Caribbean Seaway. This stable passive margin allowed for thermal subsidence to occur which began to increase due to the building up of the Cordillera Central range of Colombia. This uplift was initiated by the eastward moving Caribbean plate interacting with the Nazca and northwestern South American plate. Paleocene-Eocene The Caribbean plate has been migrating eastward from the Pacific region and eventually collided with the South American plate in the middle Paleocene. This collision transformed the passive margin of northern South America into an active margin. The Caribbean plate had subducted significant amounts of oceanic Proto-Caribbean crust by this time and was now subducting beneath the South American crust. This boundary interaction was greatly affecting the region of northwestern South America. Foreland basins formed across the region which received large amount of sediment due to the plate boundary interactions to the north. Oligocene-Holocene The Caribbean plate continued its eastward migration and continued to deform the northwestern regions of South America while also producing deformation along the northeastern regions. As plate migration proceeded, accretion along the South American plate increased. This accretion greatly influenced mountain building of the region. Uplift of the Sierra de Perijas occurred during the Oligocene whereas the Mérida Andes formed later in the middle Miocene. This uplift and subsequent erosion deposited large amount of sediment into the basin. The Maracaibo syncline formed later in this stage due to "inversion of Eocene rift-related structures". Stratigraphy The main events of sediment deposition follow the same pattern as the tectonic events, where major sedimentary formations coincide with the four tectonic stages mentioned above. Depositional history The break-up of Pangea resulted in the break-up of the Paleozoic metamorphic basement rock. The basement rock formed half-grabens where eroded sediments from the break-up were then deposited. These sediments created the metasedimentary rocks of the La Quinta formation. Development of the passive margin occurred after rifting. Characterized by carbonate and shale, the stable passive margin allowed for large amounts of clastic sediment to deposit and stay undisturbed until burial. Some of the most important source rocks come from this stage, including the La Luna and Socuy formations. The timing of the Paleogene collision is clearly recorded in the stratigraphy of the Maracaibo basin. There is an abrupt change in