Speleothems in underground spaces of the power plant Dlouhé Stráně
Abstract
Stalactites found on the concrete walls and roofs of power station adits show different structure in comparison to the cave stalactites known from carbonate karst. The adit stalactites are often constituted by unique skeletal calcite crystals with parallel orientations. The growth mechanism is opposite to cave speleothem growth mechanism: waters percolating through concrete reach supersaturation with respect to calcite after dissolving of an additional CO2 from atmosphere. In agreement with many cave stalactites, the adit stalactites are formed by pure calcite. The growth rate of the adit straw stalactite is enormous: it can reach 70 mm in length per year.