Geology of the Campanian M1 sandstone oil reservoir of eastern Ecuador: A delta system sourced from the Amazon Craton

The location of the source area of sediment was determined using U-Pb detrital zircon dating. Provenance ages are uniform within the M1 Sandstone cluster in a population that ranges from 1.4 to 1.6 billion years. These ages indicate that sands were derived mostly from erosion of the lithotectonic Rio Negro-Jurena province, located to the northeast of the studied area. Detrital ages from the overlying Maastrichtian Tena Formation include ages between 80 and 200 Ma pointing to an important change in the source areas, located in the Eastern Cordillera of Ecuador. The change in sediment supply from east to west recorded in the Tena Formation coincide with the initial episodes of the Andean orogeny, and may be driven by the collision of fragments of the Caribbean large igneous province (CLIP) against the continental margin of northwestern South America.