Lonquimay is a small, flat-topped, symmetrical stratovolcano of late-Pleistocene to dominantly Holocene age immediately SE of Tolguaca volcano. A glacier fills its summit crater and spills down the S flank. It is dominantly andesitic, but basalt and dacite are also found. There is an E-W fissure, although the prominent NE-SW Cordón Fissural Oriental fissure zone cuts across the entire volcano, that produced a series of NE-flank vents and cinder cones, some of which have been the source of voluminous lava flows, including those during 1887-90 and 1988-90 that traveled up to 10 km.
Lonquimay (left) is a small, flat-topped, symmetrical stratovolcano of late-Pleistocene to dominantly Holocene age located immediately SE of the largely Pleistocene Tolguaca volcano (extreme right). The Cordón Fissural Oriental fissure zone extends 10 km NE of Lonquimay and has produced a series of vents and cinder cones that have been the source of voluminous lava flows in historical time. Major lava flows erupted during 1887-90 and 1988-90 traveled up to 10 km from their NE-flank vents.
Photo by Norm Banks, 1990 (U.S. Geological Survey).
Last updated 2022-03-21 22:00:02