Caldera Basin

27°11′50″S 70°45′30″W / 27.19722°S 70.75833°W / -27.19722; -70.75833EtymologyCalderaRegionAtacama RegionCountry ChileState(s)CopiapóCitiesCalderaCharacteristicsOn/OffshoreOnshoreBoundariesPacific Ocean, Chilean Coast RangeHydrologyRiver(s)CopiapóGeologyPlateSouth AmericanOrogenyAndeanAgeEarly Miocene-recentStratigraphyStratigraphy

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]

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

References

Further reading

• Achurra, L.E.; J.P. Lacassie; J.P. Le Roux; C. Marquadt; M. Belmar; J. Ruiz Del Solar, and S.E. Ishman. 2009. Manganese nodules in the Miocene Bahía Inglesa Formation, north-central Chile: Petrography, geochemistry, genesis and palaeoceanographic significance. Sedimentary Geology 217. 128–139. Accessed 2017-08-15.
• Achurra, L.; C. Marquadt; J.P. Lacassie, and J.P. Le Roux. 2003. [[1] Nódulos de Mn de la Formación Bahía Inglesa: geoquímica, génesis e implicancias paleoambientales], 1–10. X Congreso Geológico Chileno. Accessed 2017-08-15.
• Acosta Hospitaleche, Carolina, and Jhoann Canto. 2005. Primer registro de cráneos asignados a Palaeospheniscus (Aves, Spheniscidae) procedentes de la Formación Bahía Inglesa (Mioceno Medio-Tardío), Chile. Revista Chilena de Historia Natural 78. 489–495. Accessed 2017-08-15.
• Chávez Hoffmeister, Martín Felipe. 2008. La ornitofauna de la Formación Bahía Inglesa, Caldera, Chile (MSc. thesis), 1–165. Universidad Austral de Chile. Accessed 2017-08-15.
• Chávez, Martín F. 2007. Sobre la presencia de Paraptenodytes y Palaeospheniscus (Aves: Sphenisciformes) en la Formación Bahía Inglesa, Chile. Revista Chilena de Historia Natural 80. 255–259. Accessed 2017-08-15.
• Chávez, Martín. 2007. Spheniscus megaramphus Stucchi et al. 2003 (Aves: Sphenisciformes) en la Formación Bahía Inglesa, Chile. Boletín de la Sociedad Geológica del Perú 102. 101–107. Accessed 2017-08-15.
• Le Roux, Jacobus P.; Luciano Achurra; Álvaro Henríquez; Catalina Carreño, and Huber Rivera. 2015. [[2] Lithostratigraphy, depositional environments and tectonic setting of the Bahía Inglesa Formation west of Copiapó, north-central Chile], 821–824. XIV Congreso Geológico Chileno. Accessed 2017-08-15.
• Oyanadel Urbina, Pablo; Jorge Carrillo Briceño; Jaime Villafaña; Victor Castelleto; Cristian Varas; Alex Alballay, and Marcelo Rivadeneira. 2015. [[3] Nuevo registro de familias de peces óseos en Formación Bahía Inglesa], 1–4. XIV Congreso Geológico Chileno. Accessed 2017-08-15.
• Staig, Felipe; Sebastián Hernández; Patricio López; Jaime A. Villafaña; Cristian Varas; Luis Patricio Soto, and Jorge D. Carrillo Briceño. 2015. Late Neogene Elasmobranch fauna from the Coquimbo Formation, Chile. Revista Brasileira de Paleontologia 18. 261–272. Accessed 2017-08-15.
• Suárez, Mario E. 2011. Línea de base paleontológica proyecto Puerto Santa Fe, 1–29. Comuna de Caldera Región de Atacama. Accessed 2017-08-15.
• Valenzuela Toro, Ana, and Carolina S. Gutstein. s.a. [[4] Mamíferos marinos fósiles (excepto Cetacea) de Formación Bahía Inglesa: Registro, implicancias paleoambientales y perspectivas de estudio]. . .. 770–772. Accessed 2017-08-15.