Cryogenic Cave Pearls In the Periglacial Zones of Ice Caves

Žák, Karel; Orvošová, Monika; Filippi, Michal; Vlček, Lukáš; Onac, Bogdan P.; Perşoiu, Aurel; Rohovec, Jan; Světlík, Ivo

doi:10.2110/jsr.2013.16

Cited by 8 publications

(2 citation statements)

References 21 publications

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“…In addition to the layering, questions remain regarding the importance of microbial activity in the growth of cave pearls (Jones & MacDonald, 1989; Jones, 2009; Melim & Spilde, 2018) and other speleothems (Jones, 2011; Pacton et al ., 2013). Early views of caves as sterile settings where microbes could be safely ignored have been replaced with a more nuanced awareness that microbes are likely important in some cave pearls, but not all cave pearls (Donahue, 1969; Jones & MacDonald, 1989; Nader, 2007; Jones, 2009; Gradziñski et al ., 2012; Zak et al ., 2013; Melim & Spilde, 2018). Research is still needed on the conditions that lead to more or less microbial involvement in cave pearls.…”

Section: Introductionmentioning

confidence: 99%

The rise and fall of cave pearl pools: Highly variable growth, recrystallization and demise of a mine pearl site

Melim

Spilde

2021

Sedimentology

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Speleothems form layered archives of the climate and local cave conditions during their formation. The origin of layering in cave pearls, however, is not well-understood. Cave pearls grown in two adjacent mine sites between 2006 and 2014 elucidate the complexity of speleothem growth and recrystallization. Site A cave pearls grew under an active drip, while Site B cave pearls grew in small rimstone-dam pools that filled with reverse-graded fitted pearls between about 2009 and 2014. Despite the variation in pool setting, all samples are layered in grey and/or brown laminations and dendrites. The order and number of these layers varies widely, even between pearls growing millimetres apart in the same pool. However, stable isotope values reflect homogenized local precipitation. The variability between adjacent samples supports control by very local factors within each pool, likely related to CO 2 degassing at the water-air interface and water flow within the confined space of each pool. Recrystallization of calcite to calcite occurs resulting in triangular microspar patches and much less obvious bladed calcite. Laminations of brown or grey 1 to 5 µm calcite crystals recrystallize to bladed calcite up 100 µm long, all the while retaining a memory of the original layers in the form of 'ghost' layers, as revealed by gentle acid etching. Pearls at the top of rimstone-dam pools grew faster than those just a few millimetres deeper, resulting in reverse grading. This model is applicable to reverse grading in marine and lacustrine pisolites. This study suggests that cave pearls in active flow regimes (drips or currents) are similar and largely abiogenic, in contrast to other locations with less flow, where more biological input is common. Recrystallization of calcite to calcite proceeds not only to equant spar (classic Ostwald ripening), but also to bladed calcite. Thus, bladed calcite in speleothems needs to be carefully evaluated for recrystallization even when aragonite is absent.

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Section: Introductionmentioning

confidence: 99%

The rise and fall of cave pearl pools: Highly variable growth, recrystallization and demise of a mine pearl site

Melim

Spilde

2021

Sedimentology

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“…19,20 Periglacial features in ice caves have been reported in the Jura Mountains in Switzerland 21 and the Carpathian Mountains of Slovakia and Romania. 22,23 They were also reported in caves that are not necessarily ice caves nor contain permafrost (cold caves in the following text) by Mitter 24 in the West Carpathian Mountains in Slovakia, the Dinaric Mountains and Alps in Slovenia [25][26][27] and in the Scandinavian Mountains of southern Norway. 28 These studies only report or describe patterned ground without a systematic study of the morphology, formation and environmental setting of these features in karst caves.…”

Section: Introductionmentioning

confidence: 91%

Sorted patterned ground in a karst cave, Ledenica pod Hrušico, Slovenia

Obu

Kosutnik

Overduin

et al. 2018

Permafrost & Periglacial

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Patterned ground is a characteristic periglacial landform in polar and alpine environments but has not been systematically studied in karst caves. Here we characterize the periglacial environment and sorted stripes within the Ledenica pod Hrušico ice cave, western Slovenia. The stripes were mapped, sediment depth and grain size were measured, and cave and outside air temperatures were monitored together with ground temperatures. Eleven sorted stripes of coarse limestone debris had developed on 1 m thick silt‐rich sediment, underlain by limestone bedrock. Silt‐rich cave sediments can accumulate as insoluble carbonate residue or during flood events, whereas coarse debris may result from frost shattering. Cold winter air entered the ice cave, but little air exchange occurred during summer, when the cave air temperature slowly rose to a maximum of 5°C. Winter temperature oscillations propagated efficiently to the snow‐free cave floor. Fourteen freeze‐thaw cycles were observed at the patterned‐ground surface during winter 2015/2016 and may cause the differential frost heaving necessary for sediment sorting. Such periglacial conditions and mixtures of silty and coarse sediments can produce sorted patterns in karst caves.

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Ice Caves in Romania

Perşoiu

Onac

2018

Cave and Karst Systems of Romania

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Cryogenic Cave Pearls In the Periglacial Zones of Ice Caves

Cited by 8 publications

References 21 publications

The rise and fall of cave pearl pools: Highly variable growth, recrystallization and demise of a mine pearl site

The rise and fall of cave pearl pools: Highly variable growth, recrystallization and demise of a mine pearl site

Sorted patterned ground in a karst cave, Ledenica pod Hrušico, Slovenia

Ice Caves in Romania

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