Many small volcanoes occuring as discrete satellite vents to large central volcanoes are also common in the Central Andes. La Poruna (21°53'S 69°30'W), a perfectly formed scoria cone, may be a satellite vent to Volcan San Pedro. This 180 m high cone has a basal diameter of 900 m and has a prominent bocca on the western side from which an 8 km long compound lava flow was erupted (Figure M15a & b). Similar young satellite vents are also associated with Chachani, Parinacota, Ollague, and Socompa volcanoes. Apart from their physical similarity, most of these lateral eruptions have two other features in common; in almost every case they are associated with regional faults or lineaments and their erupted products are the most mafic and primitive erupted from the volcano (e.g. O'Callaghan & Francis, 1986; Wörner et al., 1988).
O'Callaghan, L.J., Francis, P.W., 1986. Volcanological and petrological evolution of San Pedro volcano, Provincia El Loa, north Chile. J Geol Soc London, 143: 275-286.
Wörner, G., Harmon, R.S., Davidson, J., Moorbath, S, Turner, D.L., McMillan, N., Nye, C., Lopez-Escobar, L., and Moreno, H., 1988. The Nevados de Payachata volcanic region (18ºS/69ºW, N. Chile). I. Geological, geochemical and isotopic observations. Bull. Volcanol. 50, p287-303.