It consists of two Pleistocene lava domes reaching a maximum elevation of 4,535 metres (14,879 ft) and are of andesitic composition and older Pliocene volcanics.
[1] Yanaurcu is part of the Northern Volcanic Zone[3] of the Andes which contains the arc volcanoes of Ecuador,[4] which include Cayambe, Chachana, Cotopaxi, Illiniza, Pichincha, Pilavo, Pululagua, Reventador, Sangay, Sumaco and Tungurahua.
[6] The volcano consists of two lava domes, the larger southern Cerro Negro group and smaller northern Ñagñaro and in between Pliocene volcanics.
These three units are constructed on top of even older volcanics of andesitic-dacitic composition,[1] which crop out north and south/east of the northerly and southerly lava dome, respectively.
[6] The subduction process is further impacted by the entrainment of the Carnegie Ridge into the trench,[4] which is suspected to have influenced volcanism in Ecuador by leading to the formation of adakitic melts, a notion that is however controversial.