Open AccessVolcanism-induced karst landforms and speleogenesis, in the Ankarana Plateau (Madagascar). Hypothesis and preliminary research
Author(s) -
Éric Gilli
Publication year - 2014
Publication title -
international journal of speleology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.41
H-Index - 32
eISSN - 1827-7713
pISSN - 0392-6672
DOI - 10.5038/1827-806x.43.3.5
Subject(s) - geology , karst , plateau (mathematics) , landform , geochemistry , metamorphism , geomorphology , volcano , volcanism , canyon , cave , basalt , earth science , paleontology , tectonics , history , archaeology , mathematical analysis , mathematics
The Ankarana is a limestone plateau in the northern part of Madagascar, where a cave system, more than 120 km long, has been explored. The plateau is bordered by volcanoes and is cut across by several canyons. An analysis of surface landforms and caves suggests that the karst genesis was probably initiated by volcanism beneath an impervious cover. Volcanic bulging and magma intrusions may have favored a basalt-limestone assimilation process and metamorphism. The ascent of deep volcanic fluids (CO2 and SO2) from magma degassing and from limestone metamorphism, may explain the speleogenesis. Once denuded, the karst evolved classically, but the selective erosion of metamorphosed rocks (more likely to be weathered than pure limestone), resulted in the creation of unusual landforms such as canyons and large circular basins