Geochemistry of surface and subsurface waters in quartz-sandstones: significance for the geomorphic evolution of tepui table mountains (Gran Sabana, Venezuela)

•160 Water chemical analyses were performed on the tepui table mountains.•Chemical composition of waters is coupled with host-rock chemical analyses.•The SiO2 content is related mainly to dissolution of quartz and not to hydrolysis.•These chemical data suggest that the arenisation weathering process is active.•Quartz dissolution plays a key role in long-term geomorphic evolution of tepuis.