Juan de la Vega
25°52′S 68°48′W / 25.867°S 68.800°W[1] Juan de la Vega is a maar in Chile. It is located in the north-central Andes.[2]
Sulfur deposits are widespread in northern Chile and are associated with volcanoes, chiefly their craters and slopes. A number of these have been mined, especially in the northern segment of the area.[3] These volcanoes form part of the Central Volcanic Zone, a north-south trending volcanic arc. Notable volcanic structures close to Juan de La Vega are the Aguilar caldera and the still active Lastarria volcano;[4] Juan de la Vega is located inside the Aguilar caldera south of a resurgent dome.[5]
Juan de la Vega is found close to the Salar de La Isla.[1] It is a well preserved maar, has a diameter of 1 kilometre (0.62 mi) and a depth of 170 metres (560 ft). It is surrounded by a pyroclastic ring that contains xenoliths derived from the Paleozoic basement formations.[2] This ring is 10–30 metres (33–98 ft) thick and progressively thins outward. It covers a surface area of 6 square kilometres (2.3 sq mi).[6] One andesitic lava flow that was cut by the maar formation is 13.2 ± 0.7 million years ago. A diatreme is also associated with the maar.[2]
The maar was originally created by phreatomagmatic activity linked to a local fault. After the eruption, hydrothermal activity took place in the maar crater and left deposits of sulfur both in the maar and the surrounding pyroclastics.[2] This is an unusual deposit of sulfur as these are usually found at stratovolcanoes in the region.[1] This sulfur was prospected for mining.[7]
References
- ^ a b c Cornejo & Naranjo 1988, p. 212.
- ^ a b c d Cornejo & Naranjo 1988, p. 209.
- ^ Cornejo & Naranjo 1988, p. 211.
- ^ Cornejo & Naranjo 1988, p. 213.
- ^ Cornejo & Naranjo 1988, p. 214.
- ^ Cornejo & Naranjo 1988, p. 216,217.
- ^ Cornejo & Naranjo 1988, p. 220.
External links
- Cornejo, Paula; Naranjo, Jose A. (August 1988). "Azufrera Juan de la Vega: Un maar de origen freatomagmatico, Andes del Norte de Chile (25 52' S)" (PDF). biblioserver.sernageomin.cl (in Spanish). Santiago: 5th Chilean Geological Congress. Retrieved 3 January 2017.
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