Look up and you'll see the terrestrial vault
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Look up and you'll see the terrestrial vault

by Manuel de Paz Álvarez

The stalactites in this picture hang from subvertical Carboniferous limestone strata, deformed during the Variscan Orogeny. The reddish colours are inherited from the Fe-rich nodular limestones (Griotte) from which the calcium carbonate that constitutea the stalactites has been dissolved. Upon contact with the air of the cave, the drops loose their CO2, causing precipitation of the now-saturated calcium carbonate.
The photo was taken in the beautiful Valporquero Cave, in the province of León, northern Spain