New localities of coarsely crystalline cryogenic cave carbonates in Slovakia

Three new localities of coarsely crystalline cryogenic cave carbonates (CCCcoarse) have been recently discovered in the Western Carpathians, Slovakia. CCCcoarse are secondary mineral formations in the cave and belong to speleothems. They occur in the form of loose accumulations of calcite crystals and crystal aggregates freely deposited on the bottom of the cavities. Their genesis is interpreted as related to slow karst-water freezing in pools inside the caves, in relation to the existence of a permafrost zone during Quaternary glacials. The newly discovered CCCcoarse localities in Četníkova svadba Cave, Demänovská j. mieru Cave and Zlomísk Cave are characterized by description and photodocumentation of the present crystal forms, by preliminary C and O isotope data, and by their U-series ages. The ages of the cryogenic crystals are in the range between 47 and 12 ka BP, corresponding to the latter half of the Last Glacial. Any new locality of CCCcoarse formed during the Last Glacial represents an important source of information about paleoclimatic conditions of adjacent areas. The U-series ages of the new localities support the earlier conclusion that the formation of CCCcoarse is related to transitions from cold to warm climate periods within the Last Glacial

Cryogenic carbonates and cryogenic speleothem damage in the Za Hájovnou Cave (Javoříčko Karst, Czech Republic)

A new locality of coarse-grained cryogenic cave carbonates has been found in the Za Hájovnou Cave in Javoříčko Karst in Central Moravia, Czech Republic. Crystals and crystal aggregates, usually up to 15 mm in size, form typical loose accumulations on the surface of large fallen limestone blocks and clays covering the bottoms of several cave chambers distant from the cave entrance. The cryogenic origin of the carbonates is supported by their mode of occurrence, specific crystal and aggregate morphology, and C and O stable isotope data. U-series dating of one sample of cryogenic carbonate (age 29.5 ±0.1 ka) indicated that a period of karst water freezing occurred in marine isotope stage (MIS) 3, within the Weichselian. The cave also hosts numerous examples of speleothem damage. As shown in this paper, some of these are clearly connected with freezing conditions and cave ice action

Tracing metamorphism, exhumation and topographic evolution in orogenic belts by multiple thermochronology: a case study from the Nizke Tatry Mts., Western Carpathians

A combination of four thermochronometers [zircon fission track (ZFT), zircon (U–Th)/He (ZHe), apatite fission track (AFT) and apatite (U–Th–[Sm])/He (AHe) dating methods] applied to a valley to ridge transect is used to resolve the issues of metamorphic, exhumation and topographic evolution of the Nizke Tatry Mts. in the Western Carpathians. The ZFT ages of 132.1 ± 8.3, 155.1 ± 12.9, 146.8 ± 8.6 and 144.9 ± 11.0 Ma show that Variscan crystalline basement of the Nizke Tatry Mts. was heated to temperatures >210 °C during the Mesozoic and experienced a low-grade Alpine metamorphic overprint. ZHe and AFT ages, clustering at ~55–40 and ~45–40 Ma, respectively, revealed a rapid Eocene cooling event, documenting erosional and/or tectonic exhumation related to the collapse of the Carpathian orogenic wedge. This is the first evidence that exhumation of crystalline cores in the Western Carpathians took place in the Eocene and not in the Cretaceous as traditionally believed. Bimodal AFT length distributions, Early Miocene AHe ages and thermal modelling results suggest that the samples were heated to temperatures of ~55–90 °C during Oligocene–Miocene times. This thermal event may be related either to the Oligocene/Miocene sedimentary burial, or Miocene magmatic activity and increased heat flow. This finding supports the concept of thermal instability of the Carpathian crystalline bodies during the post-Eocene period