Main Article Content
The reconnaissance of an important rock avalanche in the Pilun Challa glacial valley (37°40´S and 71°08´W) is a consistent clue for a simple episode of glaciation on the area, fact revealed from geomorphological studies. The hypotesis had been previously proposed to the south the Caviahue-Copahue region. The huge movement originated from the southern margin of the Pilun Challa valley, as well as in many other adjacent regions, occurred after the local Pleistocene glaciation that affected the area. This complex landslide has a breakaway zone at the crest of a overstepped slope of the glacial valley and like most of the similar movements located between 36° and 38°S, it occurred during postglacial times, as suggested for their accumulations located on the previous glacial valley. A rock platform located at intermediate height between the breakaway zone and the glacial floor valley could have had an important role in the avalanche mechanics inferred for the Pilun Challa rock avalanche. Proximal avalanche deposits are therefore not connected with the distal ones, probably due the jumping of the rock mass over the ramp created by the intermediate plain. The movement obtruded the Pilun Challa valley forming an ephemeral lake upstream. The mass climbed the opposite flank of the valley forming a run-up. These avalanche deposits were identified during the first half of the 20´century as moraine accumulations due to their chaotic nature, the existence of lake deposits upstream, and transversal orientation of the morphology respect to the glacial valley. Therefore a position of ice stability was defined based on this inference, which together with other supposed glacial pulses constituted a second glaciacion. Other landslides, glacial morphologies and volcanic forms are also described in the area in the present survey.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Nota de copyright
Los autores conservan los derechos de autor y garantizan a la revista el derecho de ser la primera publicación del trabajo licenciado según una licencia de atribución Creative Commons que permite a otros compartir el trabajo con el reconocimiento de la autoría y de la publicación en la que se publicó por primera vez.
Declaración de privacidad
Los nombres y direcciones de correo electrónico introducidos en esta revista se usarán exclusivamente para los fines declarados por esta revista y no estarán disponibles para ningún otro propósito u otra persona.