Characteristics of cryogenic calcite from cave Grandioznaya (V. A. Anufrieva), Southern Ural
O. I. Kadebskaya, Y. V. Dublyansky
Section: Monitoring of anthropogenically disturbed areas
Cave Grandioznaya, discovered in 1999 in Republic Bashkortostan is one of the largest natural caves in Ural Mountains.Speleological research of the cave is conducted by the Salavat club of speleologists (Republic of Bashkortostan).Unusual calcite formations were found in the cave in 2016, as on large blocks, and on a clay bottom in free space were discovered. Using the temperature data logger HOBO Water Temp Pro v2, it was found that stable positive temperatures are observed throughout the year in the grotto where calcite was found (fluctuations do not exceed 0.5 оC). On the basis morphological, chemical and stable isotope studies, as well as the 230Th/234U dating, this calcite was found to be of cryogenic origin. Crusts are aggregates (up to 6 cm in size) of differently oriented calcite crystals with clay primers. The color tone of the crusts depends on the amount of clay particles. Finding of such calcite, formed on the transition from Younger Dryas to the Preboreal stage of the Holocene epoch is indicative of the presence of degrading permafrost in this part of
Ural at the time. During this, rather sharp, warming of the climate, an active thawing of the permafrost existed, which is a prerequisite for the formation of cryogenic calcite in caves. Methods of identification of cryogenic calcite, as well as other speleothems that remained after disappearance of underground ice, developed by the authors allows assessing the extent of ancient permafrost and its effect on karst ecosystems in the study region.
ISSN 1995-4301
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