Peculiar calcite speleothems filling fissures in calcareous sandstones and their palaeohydrological and palaeoclimatic significance: an example from the Polish Carpathians

Abstract

Peculiar calcite speleothems developed in fissures in the Cergowa Sandstones were found in the Klęczany Quarry (Polish Western Carpathians). They represent flowstone and stalactites, rafts and various sparry crusts. Such speleothems, especially phreatic ones, are uncommon in the Outer Carpathians that are composed mainly of siliciclastic rocks of flysch type, with only limited calcium carbonate content. The speleothems analysed grew in vadose and phreatic conditions as well as at the air-water interface. Phreatic speleothems and thin rafts comprise calcite crystals of eccentric morphology. Based on their stable isotope composition the majority of the speleothems form two clusters. The first is characterized by d18O values between –9.8 and –8.5‰ and of d13C values between –5.7 and –0.6‰ whereas the second cluster of samples yields d18O values between –9.4 and –7.3‰ and d13C values from –11.5 to –9.7‰. Speleothems grew between 230+14–13  ka and Holocene time. Phreatic speleothems, including massive rafts, precipitated from ascending water of deep circulation whereas vadose and water table speleothems crystallized from local infiltration water charged with soil CO2. Mixing of both waters in the shallow phreatic zone is plausible.