Juan de la Vega

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]