Volcanic Geomorphology of Costa Rica

Costa Rica has two active volcanic ranges (< 1 Ma) and several volcanically inactive ranges (1.0–29 Ma), where isolated eroded volcanic foci can be recognized. Large features are described and exemplified (i.e., calderasCaldera, andesitic shield volcanoes, stratovolcanoes, volcanic domesVolcanic dome, and pyroclastic cones)Pyroclastic cone, including their constructive basic elements (lava flowsLava Flow, debris fans, volcanic ash fields), among others small characteristic features of the volcanic landscape. Under a tropical climate, the morphology of lava flowsLava Flow with minor surface features (i.e., levees, lava fronts)Lava front can well be recognized up to 100 ka, and cratersCrater at < 350 ka, although the morphologies of cones, domes, calderasCaldera, lava platformsPlatform, and large lava fields could be preserved for longer (~ 2 Ma). IgnimbriteIgnimbrite fans and plateaus could be preserved under dry tropical forest for even longer (< 5 Ma). Volcano-tectonic features are mainly related to calderas and volcanic grabensVolcanic graben. Erosional forms and resistant elements (planezes, waterfalls, and volcanic necks) are part of the erosive pattern. The soil development and the denudation rate are more developed on the Caribbean side of the volcanic ranges than on the Pacific side due to differential orogenic rainfall and the presence of areas with hydrothermalHydrothermal alteration. Inversion of reliefInversion of relief is particularly well development on ignimbritesIgnimbrite. Along the piedmont, it is possible to recognize alluvial, fluvial, and debris avalancheDebris avalanche fans and lahars. On the Pacific OceanPacific Ocean, side of Costa Rica several representative marine landforms can recognized as seamounts (30 to 0.6 Ma), the Cocos submarine volcanic range (< 15 Ma), and an isolated subaerial volcanic island (< 2.2 Ma), the Coco Island, which emulates a guyot.