Quartzite Karst Caves


Quartzite is a sort of sandstone, and like all sandstones it consists of grains of rock, the sand and a sort of glue which glues them together. In the case of quartzites it all consists almost completely of quartz or silica (SiO2). It is formed either directly as a clastic sediment, or sandstone with a high quartz content may become quartzite during metamorphism, because the other materials are dissolved under temperature and pressure and are thus removed. It typically has a low porosity.

Quartz is probably the most resistant material in the crust, not soluble by most acids, so resistant we use it to make glas which is used for chemical factories, because it is so inert. Unfortunately it is rather brittle. But sandstone is far less brittle, because of its inner structure. A grain of sand might break, but it’s not that sure that the force will be big enough to break the next grain, or the cement between the grains. As a result quartzite, not pure quartz, is the most durable rock known.

That’s pretty bad for the formation of caves, though. What we need for caves is a material which can be removed, and that requires dissolution or at least some kind of weathering.

The Longest Quartzite Karst Caves

Cave Name Country State Length VR
Cueva Ojos de Cristal Venezuela Roraima 16,100 m 73 m
Cueva Muchimuk-Colibri Venezuela Churi 8,000 m 160 m
Cueva Charles Brewer Venezuela Churi 7,300 m 110 m
CaveGruta do Centenário Brazil Minas Gerais 4,700 m 481 m
Gruta das Torras Brazil Bahia 3,800 m 0 m
Gruta da Bocaina Brazil Inficionado 3,200 m 404 m
Cueva Juliana Venezuela Churi 3,000 m 45 m
Sima Auyan-tepuy Noroeste Venezuela Auyantepuy 2,900 m 370 m
Gruta das Bromelias Brazil Conceição do Ibitipoca (MG) 2,700 m 0 m
Cueva Zuma Venezuela Churi 2,500 m 90 m
Cueva de la Arana Venezuela Churi 2,500 m 0 m

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