Caldera Basin () is a sedimentary basin located in the coast of northern Chile west of Copiapó. The basin has a fill of marine sediments of Late Cenozoic age. With a north–south extension of and an east–west width of the basin occupies an area between the coast and the Chilean Coast Range and between the port of Caldera and the mouth of Copiapó River. The sedimentary fill rests on metamorphic rocks of Paleozoic age and on plutonic rocks of Mesozoic age.
Stratigraphy + The following units make up the sedimentary fill Name Age Lithologies Depositional environment Caldera Beds Pleistocene Bahía Inglesa Formation Quebrada Blanca Late Miocene Conglomerate, sandstone, biocalcirudite Shoreface, outer shelf, tsunami Rocas Negras Calcirudite, biocalciarenite Shoreface Mina Fosforita Sandstone, siltstone, shale Uppermost continental slope, shoreface Chorrillos Clast-supported conglomerate Submarine canyon debris flow fill, formed possibly by a tsunami La Higera Shale with gypsum veins, sandstone, siltstone, diatomaceous clay Outer shelf or uppermost continental slope Cerro Ballena Silty sandstone Supratidal flat Punta Totoral Biocalcarenite, biocalcirudite, matrix-supported conglomerate Rapid sea-level oscillations Puerto Viejo Sandstone, siltstone, claystone, shale, microcoquina Shoreface, marine transgression El Pimiento Biocalcarenite, quartzarenite Shoreface Angostura Formation Early to Mid-Miocene Matrix-supported conglomerate High-energy river mouth
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