Coranzuli is a

back-arc A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of ...

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

in the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

, related to the Altiplano-Puna volcanic complex. It formed along the Lipez geological lineament about 6.6 million years ago. Volcanic ash samples found in the Coastal Cordillera of

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

may come from this volcano. The Rachaite () stratovolcano is located close to the caldera. The formation of this caldera has been influenced by a number of local fault systems, the Coyaguayama and Rachaite lineaments. Marine sediments of

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ...

age with some later volcanic intrusions form the basement together with

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

sediments. Three cycles of volcanic activity preceding the Coranzuli ignimbrite have been identified. The Coranzuli system is part of a Late Miocene volcanic episode that also includes Aguas Calientes, Cerro Panizos and the Toconquis ignimbrite of Galan. The Morro Grande Formation may have originated by volcanic activity in the area of Cerro Coranzuli. 6.8 to 6.4 million years ago, this caldera erupted the Coranzuli ignimbrites. They have a total volume of . They are named in order from oldest to youngest Abra Grande ignimbrite, Potreros ignimbrite, Las Termas ignimbrites 1 and 2, and a smaller one Corral de Sangre. They are most likely the products of the same eruption. The Coranzuli Ignimbrite was erupted in three distinct flows, the last one is the largest one and has the highest matrix component. This ignimbrite is of

rhyodacitic Rhyodacite is a volcanic rock intermediate in composition between dacite and rhyolite. It is the extrusive equivalent of those plutonic rocks that are intermediate in composition between monzogranite and granodiorite. Rhyodacites form from rapid ...

composition. The Las Termas Ignimbrite contains pumice and is highly welded and crystalline. A wide caldera was left by the eruption that formed this ignimbrite and postcaldera volcanism generated three thick

dacitic Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite ...

lava flows within it. The Cerro Coranzuli lava dome was erupted subsequently. A major

seismic Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...

velocity anomaly is found beneath Coranzuli volcano.

References

{{DEFAULTSORT:Coranzuli (caldera) Volcanoes of Jujuy Province Calderas of Argentina Miocene calderas