Geological research suggests that the South American plate is moving west away from the Mid-Atlantic Ridge: "Parts of the plate boundaries consisting of alternations of relatively short transform fault and spreading ridge segments are represented by a boundary following the general trend."[2] As a result, the eastward-moving and more denseNazca plate is subducting under the western edge of the South American plate, along the continent's Pacific coast, at a rate of 77 mm (3.0 in) per year.[3] The collision of these two plates is responsible forlifting the massiveAndes Mountains and for creating the numerousvolcanoes (including bothstratovolcanoes andshield volcanoes) that are strewn throughout the Andes.[4][5]
Gómez Tapias, Jorge; Montes Ramírez, Nohora E.; Almanza Meléndez, María F.; Alcárcel Gutiérrez, Fernando A.; Madrid Montoya, César A.; Diederix, Hans (2015).Geological Map of Colombia.Servicio Geológico Colombiano. pp. 1–212. Retrieved2019-10-29.
