Quaternary tectonic and climate changes at the origin of travertine and calcrete in the eastern Betics (Almería region, SE Spain)

Abstract

Continental carbonate bodies are widespread in the Tabernas basin, eastern Betic Cordillera. Their relationships with the topographic evolution, climate changes and extensional regional tectonic processes recognized in the region are, however, still unclear. Travertine deposits exhibit facies of cascade and pool environments often reported as related to water–air surface processes. Calcretes show a large panel of facies, indicating control by groundwater and pedogenic processes. New U/Th dates on both travertine and calcrete reveal that they precipitated from 354 ka ± 76 to 8 ka ± 0.2. The U/Th dates obtained on calcretes are in good agreement with global climate changes and support that precipitation of recent CaCO3 is episodic and occurs mainly during warm and wet conditions. C and O stable isotope geochemistry reveals travertines are thermogenic and characterized by hydrothermal fluids enriched in CO2 that interacted with aquifers. This thermogenic origin suggests a deep source of CO2 (higher positive δ13C values) likely triggered by the presence of an anomalously hot mantle that reflects thinning of the regional lithosphere and volcanism. Further analyses of the distribution of calcrete show they are carbonate-rich fluvial terraces, whose formation is controlled by the response of the river network to regional uplift and climate.Supplementary Materials: reproducibility for δ13C and δ18O of the NSB-18 internal standard available in Supplementary Table 1 (SP1) and reproducibility for U and Th of the HU-1 standard available in Supplementary Table 2 (SP2) at https://doi.org/10.6084/m9.figshare.c.4996514