Early to Middle Holocene aridification trend in southeastern Iberia and the termination of the last North African Humid Period revealed by a multi-proxy speleothem record
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Le résumé fourni par la source
Abstract. During the Early Holocene, relatively humid conditions prevailed across northern Africa, transitioning to a drier climate by the end of the mid-Holocene. While the timing and nature of this climatic shift are well-established in the Maghreb region of Africa, uncertainties remain regarding the pace of the wet-to-dry transition in the southern Iberian Peninsula. We present a multi-proxy stalagmite record from Simarrón II cave, spanning 9.7 to 4.4 ka BP. The dataset combines stable carbon and oxygen isotopes in calcite (δ18Ocarb, δ13C), Mg/Ca ratios, petrographic observations, fluid inclusion isotopes (δ18Ofi, δ2H) and TEX₈₆-derived paleotemperatures to reconstruct paleohydrological and climatic changes. From 9.7 to 4.4 ka, progressively higher δ¹⁸Ofi and δ²H values, coupled with decreasing deuterium excess, are consistent with a gradual shift in rainfall seasonality and/or moisture sources (i.e., frontal Atlantic-type precipitation regime during the early Holocene to a more convective Mediterranean regime). This trend could be overprinted by enhanced soil and in-cave water evaporation during the late Mid-Holocene because of climate aridification. Lower δ18Ocarb, δ13C, and Mg/Ca values between 9.7 and 6.0 ka also indicate relatively wet conditions during the early Holocene and part of the middle Holocene. From ~6.0 ka onward, these proxies show a progressive increase, stabilizing after ~5.5 ka, consistent with a climate shift toward more arid conditions that occurred within ~500 yrs. This is interpreted as reflecting enhanced prior calcite precipitation rates and kinetic isotope effects associated with intensified in-cave CO₂ degassing, due to the dry climate during the termination of the last North African Humid Period. Paired δ18Ocarb– δ18Ofi paleotemperature estimates yield unrealistically high values (20–30 °C) for most of the investigated period, further supporting non-equilibrium fractionation processes and likely in-cave water evaporation. In contrast, TEX86-based temperatures (13–17 °C) suggest that early–mid Holocene cave temperatures were higher than present-day values in the cave (11.7 °C).
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Le contrôle bibliographique ouvert
DOI retrouvé dans Crossref DOI retrouvé ; titre concordant.
- Titre Crossref
- Early to Middle Holocene aridification trend in southeastern Iberia and the termination of the last North African Humid Period revealed by a multi-proxy speleothem record
- Date Crossref
- 07/08/2026
- Éditeur
- Copernicus GmbH
- Type
- posted-content
Ce recoupement confirme des métadonnées liées au DOI. Il ne confirme ni la méthode ni les conclusions de l’étude, et il ne compte pas comme une seconde source scientifique indépendante.
Où se fait cette recherche
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University of Almería Building CITE V pays non établi dans la noticeUniversité ou école supérieure
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Max Planck Institute for Chemistry Climate Geochemistry Department pays non établi dans la noticeStructure de recherche
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Xi'an Jiaotong University Institute of Global Environmental Change pays non établi dans la noticeUniversité ou école supérieure
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University of Pisa Department of Earth Sciences pays non établi dans la noticeUniversité ou école supérieure
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Ospedale Santa Maria pays non établi dans la noticeÉtablissement de santé
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Colby College Department of Earth Sciences pays non établi dans la noticeUniversité ou école supérieure
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University of Alaska Anchorage Department of Chemistry pays non établi dans la noticeUniversité ou école supérieure
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Universidad de Burgos pays non établi dans la noticeUniversité ou école supérieure
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Área de Paleontología pays non établi dans la noticeInstitution
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Department of Biology and Geology pays non établi dans la noticeInstitution
Building CITE V — University of Almería, Climate Geochemistry Department — Max Planck Institute for Chemistry et Institute of Global Environmental Change — Xi'an Jiaotong University, avec 7 autres affiliations.
Une affiliation ne permet pas de déduire la nationalité d’un auteur.