a large contribution from atmospheric air and an important role for a hydrothermal system. Other Purico has been quarried for building materials, and many buildings in San Pedro de Atacama were built from rocks quarried there. , Alitar was under investigation as a potential source of geothermal power. Two sulfur deposits occur at Purico, the first southeast of Cerro Toco and the second at Alitar. The Purico deposit in 1968 was estimated to feature 4 million tons of caliche with a grade of 50%, while the Alitar deposit in that year amounted to 1.5 million tons of caliche with a grade of 60%. In the 1950s and as recently as 1993, sulfur was mined on Purico and transported by truck to San Pedro de Atacama where it was processed. In 1993, production of sulfur amounted to . The Purico complex is the site of a number of astronomical observatories, including but not limited to the Llano de Chajnantor Observatory and the Atacama Large Millimeter Array. In 1998, the Cerro Chascón Science Preserve was established on Purico, which among other things disallows mining in the area of the preserve. This Science Preserve covers most of the Purico complex. See also List of volcanoes in Chile Ignimbrite Salar de Atacama Notes References Sources Further reading Crustal architecture and magma dynamics in a large continental magmatic system: a case study of the Purico-Chascon Volcanic Complex, Northern Chile External links Stratovolcanoes of Chile Atacama Desert Pyroclastic shields Landforms of Antofagasta Region Geology of Antofagasta Region