The Quaternary deposits of Chile are generally classified according to their mode of deposition and the physiographic province in which they occur. Lacustrine, fluvial, mudflow, and eolian deposits occur in the Cordillera de la Costa, Central Valley, Altiplano, Cordillera de los Andes, and in Magallanes. In addition, deltaic and terrace deposits occur in coastal areas, and glacial deposits in the Central Valley, Cordillera de los Andes, and Magallanes.
Quaternary volcanic deposits are present in all physiographic provinces, although in the Central Valley, Cordillera de la Costa, and along the shore of the Pacific they are mostly water-laid tuffs. Flows and pyroclastics are distributed throughout large areas of the Altiplano and the Cordillera de los Andes, and in a few isolated areas in Magallanes. The composition of the Quaternary tuffs of Chile ranges from rhyolitic to basaltic, but the lavas are basaltic or andesitic.
The deposits have been very little warped or tilted, but they have been affected by displacements of fault blocks and by epeirogenic movements. The net results of epeirogeny have been general uplift of the coast north of Puerto Montt and general subsidence to the south.