Caldera Basin

Caldera Basin (Spanish: Cuenca de Caldera) 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 43 kilometres (27 mi) and an east–west width of 20 kilometres (12 mi) 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.^[1]

Caldera Basin
Cuenca de Caldera
Coordinates	27°11′50″S 70°45′30″W
Etymology	Caldera
Region	Atacama Region
Country	Chile
State(s)	Copiapó
Cities	Caldera
Characteristics
On/Offshore	Onshore
Boundaries	Pacific Ocean, Chilean Coast Range
Hydrology
River(s)	Copiapó
Geology
Plate	South American
Orogeny	Andean
Age	Early Miocene-recent
Stratigraphy	Stratigraphy

Stratigraphy

The following units make up the sedimentary fill^[1]

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