Cerro Redondo is a

lava dome In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruption ...

complex in the northern Puna, north of Rinconada. It is situated over the

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

basement east of the Sierra de Rinconada. The lava domes were erupted along ring fractures on a preceding fall deposit containing blocks and

breccia Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of d ...

. Another report indicates just one isolated dacite dome. Intense hydrothermal alteration has occurred on the lavas. The breccia and pyroclastics are 12.54±1.1

mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal assistant created by Motorola * Mya (TV channel), an Italian Television channel * Midwest Young Artists, a comprehensive youth music program Codes * Burmese ...

old, determined from

fission track Ion tracks are damage-trails created by swift heavy ions penetrating through solids, which may be sufficiently-contiguous for chemical etching in a variety of crystalline, glassy, and/or polymeric solids. They are associated with cylindrical d ...

dating of

apatite Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common ...

. The complex may be linked to a

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 ...

together with the neighbouring Chinchillas and Pan de Azúcar centres. Each of them is associated with mineral deposits which were mined on Pan de Azúcar. Cerro Redondo's breccia is flanked by normal faults and one reverse fault is located within the complex.

References

{{Volcanology-stub Volcanoes of Jujuy Province Miocene lava domes