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Megafan formation driven by explosive volcanism and active tectonic processes in a humid tropical environment
Author(s) -
Galve Jorge P.,
Alvarado Guillermo E.,
PérezPeña José Vicente,
Mora Mauricio M.,
BoothRea Guillermo,
Azañón José Miguel
Publication year - 2016
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12236
Subject(s) - geology , volcanism , volcano , fluvial , earth science , landslide , quaternary , bedrock , debris , tectonics , geomorphology , geochemistry , paleontology , oceanography , structural basin
Quaternary volcanism in the Central Cordillera of Costa Rica has created an orographic barrier that concentrates rainfall on its northern side. This humid climate produces weathered bedrock prone to landsliding. Ash fall from explosive eruptions kills the vegetation cover and intensifies erosion processes. These eruptions, hydrothermal activity and associated earthquakes destabilize the slopes of river valleys, and even the volcanic edifices, producing landslides and large debris avalanches. All these processes mobilize an extra sediment input that is deposited in the piedmont lowlands forming the Santa Clara megafan. The megafans described in the literature mainly grow according to climatic fluctuations; however, sedimentation in the Santa Clara megafan is also controlled by endogenic processes with longer recurrence periods. Analysis of this megafan provides new insight into the origin and evolution of these landforms. In volcanic regions, active volcanism should be considered when investigating the formation of some megafans.