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Last Glacial Maximum cryogenic calcite deposits in an alluvial fan at Villetoureix, southwest France

hal.structure.identifierDe la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie [PACEA]
hal.structure.identifierInstitut national de recherches archéologiques préventives - Centre de recherches archéologiques de Bègles [Inrap, Bègles]
dc.contributor.authorBERTRAN, Pascal
hal.structure.identifierEnvironnements, Dynamiques et Territoires de Montagne [EDYTEM]
hal.structure.identifierUniversity of Melbourne
dc.contributor.authorCOUCHOUD, Isabelle
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorCHARLIER, Karine
hal.structure.identifierGéochrononologie Traceurs Archéométrie [GEOTRAC]
hal.structure.identifierLaboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
hal.structure.identifierSilesian University of Technology
dc.contributor.authorHATTÉ, Christine
hal.structure.identifierArchéosciences Bordeaux
dc.contributor.authorLEFRAIS, Yannick
hal.structure.identifierLaboratoire de géographie physique : Environnements Quaternaires et Actuels [LGP]
dc.contributor.authorLIMONDIN-LOZOUET, Nicole
hal.structure.identifierDe la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie [PACEA]
dc.contributor.authorQUEFFELEC, Alain
dc.date.issued2023-03-20
dc.identifier.issn1045-6740
dc.description.abstractEnThe origin of white calcite silts forming 0.5 to 3-cm-thick lenses in alluvial fan deposits 14C-dated to the Last Glacial Maximum in the Dronne Valley (Dordogne, southwest France) is investigated using microscopic imagery, chemistry, and O and C stable isotopes. The calcite silts, composed mainly of aggregates of 3–5-μm euhedral crystals, do not resemble secondary precipitations of pedological origin because of the strata-like pattern and the lack of clearly identifiable biological structures. Their association with evidence of ice formation in the soil (platy structure, involutions) suggests that they were deposited in a deep seasonal frost context. Their isotopic composition differs significantly from those of detrital carbonates and of Holocene bioprecipitation and seems to be best explained by precipitation under closed-system conditions. Calculation of the isotopic composition of calcite that would have formed in equilibrium with groundwater of regional LGM aquifers provides values that are in the range of the composition of the calcite silts for a precipitation temperature close to 0°C. Therefore, these deposits are interpreted as cryogenic calcite precipitated from waters close to saturation with respect to calcite freezing at the base of/within icings or within the ground, possibly from frost blisters. Similar calcite precipitation at the outlet of karstic springs may have been abundant in the calcareous terrains of southwest France during the LGM, although still unrecognized in the geological record.
dc.language.isoen
dc.publisherWiley
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/
dc.subject.encryogenic calcite
dc.subject.enicing
dc.subject.enLast Glacial Maximum
dc.subject.enmalacofauna
dc.subject.enO and C stable isotopes
dc.subject.ensouthwest France
dc.title.enLast Glacial Maximum cryogenic calcite deposits in an alluvial fan at Villetoureix, southwest France
dc.typeArticle de revue
dc.identifier.doi10.1002/ppp.2183
dc.subject.halSciences de l'environnement
bordeaux.journalPermafrost and Periglacial Processes
bordeaux.page244-258
bordeaux.volume34
bordeaux.issue2
bordeaux.peerReviewedoui
hal.identifierhal-04038659
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-04038659v1
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