A group of young basaltic volcanoes lies in Argentina near the Chilean border, south of Lanín volcano. The Huanquihué volcano group consists of a NNE-SSW-trending chain of stratovolcanoes of Pleistocene age, some of which lie along the border. A Holocene compound cinder cone with three nested craters up to 400 m in diameter that occupied a valley NE of Cerro Huanquihué and a tuff cone constructed within glacial Lake Epulafquen lies at the northern end of the chain. Growth of this Holocene tuff cone, La Angostura ("The Narrowing"), created a peninsula that formed a narrow channel connecting Lake Epulafquen and Lake Huechulafquen. A very recent lava flow from the base of the Achín-Niellu cinder cone (also known as Cerro Escorial) traveled north into glacial Lago Epulafquen, forming a prominent lava delta. The Escorial lava flow is an extremely youthful flow that diverted local drainages and formed new lakes. A radiocarbon date of about 200 years before present was obtained from this flow, and local residents recount oral histories of the eruption, which was observed by their grandparents.