Cryogenic Carbonates in Cave Environments: A Review

Authors

Karel Žák, Institute of Geology AS CRFollow
Bogdan P. Onac, University of South FloridaFollow
Aurel Perşoiu, University of South FloridaFollow

Document Type

Article

Publication Date

8-2008

Digital Object Identifier (DOI)

https://doi.org/10.1016/j.quaint.2007.02.022

Abstract

Cryogenic cave carbonate (CCC) represents a specific type of speleothem. Its precipitation proceeds at the freezing point and is triggered by freezing-induced concentration of solutes. Compared to classical speleothems (stalagmites, flowstones), CCC occurs as accumulations of loose uncemented aggregates. The grain sizes range from less than 1 μm to over 1 cm in diameter. Karst groundwater chemistry and its freezing rate upon entering the cave are responsible for highly variable grain morphology. Rapid freezing of water results in the formation of CCC powders with grain size typically below 50 μm. Slow freezing of water in caves (usually in systems where the CO₂ escape is partly restricted; e.g., ice covered water pools) results in the formation of large mineral grains, with sizes from less than 1 mm to about 20 mm. The range of carbon and oxygen stable isotope compositions of CCC is larger than for a typical carbonate speleothem. Rapid freezing of water accompanied by a quick kinetic CO₂ degassing results in large ranges of δ¹³C of the CCC powders (between –10‰ and +18‰ PDB). Slow freezing of water, with a restricted CO₂ escape results in gradual increase of δ¹³C values (from −9‰ to +6‰ PDB; data ranges in individual caves are usually much more restricted), accompanied by a δ¹⁸O decrease of the precipitated carbonate (overall range from −10‰ to −24‰ PDB). These unusual trends of the carbonate δ¹⁸O evolution reflect incorporation of the heavier ¹⁸O isotope into the formed ice. New isotope data on CCC from three Romanian ice caves allow better understanding of the carbon and oxygen isotope fingerprint in carbonates precipitated from freezing of bulk water. CCCs are proposed as a new genetic group of speleothems.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Quaternary International, v. 187, issue 1, p. 84-96

Scholar Commons Citation

Žák, Karel; Onac, Bogdan P.; and Perşoiu, Aurel, "Cryogenic Carbonates in Cave Environments: A Review" (2008). Geology Faculty Publications. 101.
https://digitalcommons.usf.edu/gly_facpub/101

Full Text URL

https://doi.org/10.1016/j.quaint.2007.02.022