The orbicular granodiorite of Recoba Hill in the North Patagonian Batholith
Journal
Andean Geology
ISSN
0718-7106
Date Issued
2025-01-31
Author(s)
Aníbal Soto
Francisco Hervé
Gianfranco Gregorina
Type
journal-article
Abstract
A small body of orbicular granodiorite crops out on the Recoba Hill, immediately east of the town of Chaitén, in the mainland area called Chiloé continental, in southern Chile. The rock comprises cm-sized igneous cores with a single shell of fine-grained plagioclase-quartz-K-feldspar assemblages. It is hosted in a Miocene granodiorite, and it is crosscut by aplite and mafic dikes. No other mention of orbicular rocks has to date been reported for the >1,000 km long North Patagonian Batholith, suggesting that the conditions necessary for their formation were infrequent. Thermobarometric determinations indicate pressures lower than 2 kbar (less than 6 km depth) for its formation, a level much shallower than the estimated source depth of the older rocks of the batholith.
Project(s)
Subjects
chaiten
;
chile
;
los lagos
;
aplite
;
barometry
;
batholith
;
granodiorite
;
mafic rock
;
miocene
;
chaitén
;
hornblende geothermobarometry
;
miocene intrusives
;
orbicular rocks
;
patagonian batholith