Coquimbo Formation

The Coquimbo Formation (previously known as Piso de Coquimbo or Coquimbo Stufe) is a littoral, sedimentary, and fossiliferous geological formation that chiefly crops out along the coast of the Coquimbo Region, Chile. It is dated back to the Miocene to Middle Pleistocene. The lithology of the formation comprises sands, sandstones, siltstones, limestones, coquinas, and conglomerates. The strata and facies of the Coquimbo Formation reflect a complex marine depositional history, varying from deep to shallow water paleoenvironments controlled by tectonic events and turbulent, successive changes in sea the level that developed large marine terraces within the strata which is recorded in the form of marine transgressions and regressions.

The Coquimbo Formation preserves a rich fossil marine assemblage, including molluscs, barnacles, brachiopods, fish, seabirds, and marine mammals such as cetaceans and aquatic ground sloths. As a whole, the paleoenvironments, and paleofauna of the formation have experienced strong changes and sucessions through time mainly due to large climatic and tectonic events. In both lithology and fossil content the Coquimbo Formation is very similar to other units of South America, such as the Pisco Formation of Peru or Bahía Inglesa Formation of the Atacama Region, which is also found in Chile.