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Impact of Bolivian paleolake evaporation on the ?18O of the Andean glaciers during the last deglaciation (18.5-11.7 ka): Diatom-inferred ?18O values and hydro-isotopic modeling

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dc.creatorQuesada, Benjamín Raphael
dc.creatorSylvestre, Florencespa
dc.creatorVimeux, Françoisespa
dc.creatorBlack, Jessicaspa
dc.creatorPaillès, Christinespa
dc.creatorSonzogni, Corinnespa
dc.creatorAlexandre, Annespa
dc.creatorBlardd, Pierre-Henrispa
dc.creatorTonetto, Alainspa
dc.creatorMazura, Jean-Charlesspa
dc.creatorBruneton, Hélènespa
dc.date.accessioned2020-08-19T14:44:14Z
dc.date.available2020-08-19T14:44:14Z
dc.date.created2015-07-12spa
dc.description.abstractDuring the last deglaciation, the Bolivian Altiplano (15–23°S, 66–70°W) was occupied by paleolake Tauca covering, at least, ?51,000 km2 at its maximum highstand between 16.5 and 15 ka. Twenty-five hundred years later, after a massive regression, a new transgressive phase, produced paleolake Coipasa, smaller than Tauca and restricted to the southern part of the basin. These paleolakes were overlooked at the west by the Sajama ice cap. The latter provides a continuous record of the oxygen isotopic composition of paleo-precipitation for the last 25 ka. Contemporaneously to the end of paleolake Tauca, around 14.3 ka, the Sajama ice cap recorded a significant increase in ice oxygen isotopic composition (?18Oice). This paper examines to what extent the disappearance of Lake Tauca contributed to precipitation on the Sajama summit and this specific isotopic variation. The water ?18O values of paleolakes Tauca and Coipasa (?18Olake) were quantitatively reconstructed from 18.5 to 11.7 ka based on diatom isotopic composition (?18Odiatoms) and ostracod isotopic composition (?18Ocarbonates) retrieved in lacustrine sediments. At a centennial time scale, a strong trend appears: abrupt decreases of ?18Olake during lake fillings are immediately followed by abrupt increases of ?18Olake during lake level stable phases. The highest variation occurred at ?15.8 ka with a ?18Olake decrease of about ?10‰, concomitant with the Lake Tauca highstand, followed ?400 years later by a 7‰ increase in ?18Olake. A simple hydro-isotopic modeling approach reproduces consistently this rapid “decrease–increase” feature. Moreover, it suggests that this unexpected re-increase in ?18Olake after filling phases can be partly explained by an equilibration of isotopic fluxes during the lake steady-state. Based on isotopic calculations during lake evaporation and a simple water stable isotopes balance between potential moisture sources at Sajama (advection versus lake evaporation), we show that total or partial evaporation (from 5 to 60%) of paleolake Tauca during its major regression phase at 14.3 ka could explain the pronounced isotopic excursion at Sajama ice cap. These results suggest that perturbations of the local hydrological cycle in lacustrine areas may substantially affect the paleoclimatic interpretation of the near-by isotopic signals (e.g. ice core or speleothems).eng
dc.format.mimetypeapplication/pdf
dc.identifier.doihttps://doi.org/10.1016/j.quascirev.2015.04.022
dc.identifier.issnISSN: 0277-3791
dc.identifier.issnEISSN: 1873-457X
dc.identifier.urihttps://repository.urosario.edu.co/handle/10336/27849
dc.language.isoengspa
dc.publisherElsevierspa
dc.relation.citationEndPage106
dc.relation.citationStartPage93
dc.relation.citationTitleQuaternary Science Reviews
dc.relation.citationVolumeVol. 120
dc.relation.ispartofQuaternary Science Reviews, ISSN: 0277-3791;EISSN: 1873-457X, Vol.120 (2015); pp. 93-106 spa
dc.relation.urihttps://www.sciencedirect.com/science/article/abs/pii/S0277379115001808spa
dc.rights.accesRightsinfo:eu-repo/semantics/restrictedAccess
dc.rights.accesoRestringido (Acceso a grupos específicos)spa
dc.sourceQuaternary Science Reviewsspa
dc.source.instnameinstname:Universidad del Rosario
dc.source.reponamereponame:Repositorio Institucional EdocUR
dc.subject.keywordBolivianspa
dc.subject.keywordAltiplanospa
dc.subject.keywordDeglaciationspa
dc.subject.keywordPaleolakesspa
dc.subject.keywordAndean ice coresspa
dc.subject.keywordDiatomsspa
dc.subject.keywordOstracodsspa
dc.subject.keywordOxygen isotopesspa
dc.titleImpact of Bolivian paleolake evaporation on the ?18O of the Andean glaciers during the last deglaciation (18.5-11.7 ka): Diatom-inferred ?18O values and hydro-isotopic modelingspa
dc.title.TranslatedTitleImpacto de la evaporación del paleolaco boliviano en el ?18O de los glaciares andinos durante la última desglaciación (18,5-11,7 ka): valores de ?18O inferidos por diatomeas y modelado hidroisotópicospa
dc.typearticleeng
dc.type.hasVersioninfo:eu-repo/semantics/publishedVersion
dc.type.spaArtículospa
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