285 research outputs found
El Cuaternario al E. de Huesca
Se describen los depósitos cuaternanos existentes al Este de Huesca, su distribución espacial y los procesos que los han afectado a lo largo de su historia geológica reciente. También se analiza el fenómeno de captura por derrame del río Guatizalema en favor del rio Flumen
At the beginnings of the funerary Megalithism in Iberia at Campo de Hockey necropolis
The excavations undertaken at the Campo de Hockey site in 2008 led to the identification of a major Neolithic necropolis in the former Island of San Fernando (Bay of Cádiz). This work presents the results of the latest studies, which indicate that the site stands as one of the oldest megalithic necropolises in the Iberian Peninsula. The main aim of this work is to present with precision the chronology of this necropolis through a Bayesian statistical model that confirms that the necropolis was in use from c. 4300 to 3800 cal BC. The presence of prestige grave goods in the earliest and most monumental graves suggest that the Megalithism phenomenon emerged in relation to maritime routes linked to the distribution of exotic products. We also aim to examine funerary practices in these early megalithic communities, and especially their way of life and the social reproduction system. As such, in addition to the chronological information and the Bayesian statistics, we provide the results of a comprehensive interdisciplinary study, including anthropological, archaeometric and genetic data.We wish to express our gratitude to Antonio Sáez Espligares (Historical Museum of San Fernando) and Lourdes Lorenzo (Figlina, s.l.) for their support during the archaeological excavation. This research was conducted in the framework of the following research projects: “Analysis of prehistoric societies from the Middle Palaeolithic to the Late Neolithic at both sides of the Strait of Gibraltar: relations and contacts”, funded by the State Research Agency (SRA) and the European Regional Development Fund (ERDF). Ref.: HAR2017-87324-P. (2018–2021). “Análisis interdisciplinar para el conocimiento del poblamiento humano de la Bahía de Cadiz durante la Prehistoria Reciente (VI-II milenios a.n.e.)”, funded by 2014–2020 ERDF Operational Programme and the Department of Economy, Knowledge, Business and University of the Regional Government of Andalusia. Ref.: FEDERUCA18-106917 (2020–2023). “Análisis de los isótopos de oxígeno en conchas y de los isótopos estables de oxígeno y carbono en huesos humanos en el poblado neolítico insular de Campo de Hockey (San Fernando, Cádiz)”, authorised and funded by CEIMAR. Ref.: CEIJ-015 (2018–2019). Eduardo Molina Piernas acknowledges co-funding from European Social Fund (D1113102E3) and Junta de Andalucía
U-series dating applied to speleothems from Los Covachos Cave, South of Spain
U-Series dating method is applied to speleo thems from Los Covachos Cave in the south of Spain. A
combination of solvent extraction method with ion exchange resins is used for uranium and thorium isotopes.
Uranium concentrations are low and for younger samples
correction by detrital contamination is necessary. Ages
obtained range from 30 to 135 ky with a hiatus between 50
and 80 ky BP. Changes in uranium isotopes activity ratios
indicate a change in climatic conditions
U/Th dating of impure carbonates: 230Th/232Th activity ratios in detrital material
In environmental age dating the 230Th/232Th activity ratio is widely used as an indicator of detrital contamination. A
clear relationship between this activity ratio and the carbonate sample’s age has previously been demonstrated, whereby a
detrital correction must be applied when the 230Th/232Th activity ratio of the leach drops to 20. We demonstrate that in
some cases carbonate samples with 230Th/232Th well above 20 must be corrected, otherwise an overestimation of the
sample’s age is obtained. Evaluation of the relationship between 230Th/234U and 230Th/232Th in the carbonate’s aliquots
will enable evalua-tion of the limit at which a carbonate can be considered pure or impure.European Union (UE) EU MEDOC Programme: 2002-02-4.1-U-04
U-series dating of speleothems from the Sierra del Endrinal (Grazalema Mountains, S Spain)
The uranium-series method is applied to date relic flowstone from karstic mountains in the south of Spain.
Geomorphological mapping shows three staircased erosion surfaces with a typical karst landform. Exhumed flowstones
fill the surficial palaeosinkholes and open fractures. Some of the samples analysed were impure carbonates
consequently the leachate–leachate method was used to obtain activity ratios in the carbonate fraction. The ages
obtained range from 34.4 ky to 266 ky and are grouped in four periods: 30–50 ky, 90–110 ky, 150 ky and 230–270 ky. All
these periods are related to the warm climate oxygen isotope stages 3 and 5. Practically all locations present secular
equilibrium in uranium isotopes
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