The geomorphological evolution of the Paricutin cone and lava flows, Mexico, 1943-1990

Erosion and sedimentation processes in the Paricutin cone and adjacent lava fields have been evaluated 47 years after the eruption through field study of the morphological characteristics of the area. Previous studies indicate an initial stage of accelerated erosion, decreasing quickly after the stripping of the ash layers and cessation of the volcanic activities. In the cone and crater area, revegetation is the main process, after the first stage of stripping of fine ash. The lava fields are the least affected areas by erosional processes, with vegetation development in minor depressions, crevices and along the edges of the lava flows. The "llanos" or lava dammed plains, are the most active physiographic units, with continuous deposition of sediments. They are completely covered by vegetation or under agricultural use. Incision of channels along the lava field edge promotes the integration of the drainage system, but still most of the affected area drains into the lave field. Present erosion rates are higher than normal rates, and a complete rehabilitation of the pyroclastic area may extend over decades. Filling of sediments and revegetation of the lava fields will develop in a longer period of several millennia.