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Revista geológica de Chile

versión impresa ISSN 0716-0208

Resumen

CLAVERO R., Jorge E.; SPARKS, Stephen J.; POLANCO, Edmundo  y  PRINGLE, Malcolm S.. Evolution of Parinacota volcano, Central Andes, Northern Chile. Rev. geol. Chile [online]. 2004, vol.31, n.2, pp. 317-347. ISSN 0716-0208.  http://dx.doi.org/10.4067/S0716-02082004000200009.

Parinacota is an active composite stratovolcano located in the Central Andes of Northern Chile (18°S). During its earlier stage (Parinacota 1 unit, Late Pleistocene, 300-70? ka) rhyolitic to andesitic magmas were erupted, forming a voluminous lava-dome complex with its associated pyroclastic fans (mainly block-and-ash flow deposits), essentially deposited towards the Upper Lauca basin (West). It later evolved to a steep-sided composite stratocone (Parinacota 2 unit, Late Pleistocene-Holocene, 70?-8 ka), mainly formed by andesitic lava flows and scoria tephra fallout deposits.Around 8 ka ago the ancestral Parinacota volcano, built during Parinacota 1 and 2, partially collapsed towards the west, in a single and catastrophic event generating the outstanding Parinacota Debris Avalanche deposit.Soon after the collapse a new stratocone started to build with the emission of andesitic lava flows and pyroclastic flows, and their associated fallout deposits (Parinacota 3 unit, Holocene, <8 ka). Some lahars mainly directed towards the south, west and east have also been generated during Parinacota 3. Contemporaneously with the formation of the central cone, a series of flank cones and their associated basaltic andesite to andesitic lava flows were formed (Ajata centres, 6-1.4 ka). These centres erupted through two fractures, NNE and NS oriented, in the south-western flank of the volcano. The new cone (Parinacota 3 unit) has an estimated minimum volume of 18 km3, giving a minimum eruption rate of 2.25 km3 ka-1 for the last 8,000 years, which means that Parinacota volcano must be considered one of the most active volcanoes in the Central Andes of Northern Chile during the Holocene

Palabras clave : Eruption rate; Debris avalanche; Holocene; Parinacota; Chile.

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