New luminescence ages for the Galería Complex archaeological site: resolving chronological uncertainties on the acheulean record of the Sierra de Atapuerca, northern Spain

PLoS One. 2014 Oct 22;9(10):e110169. doi: 10.1371/journal.pone.0110169. eCollection 2014.

Abstract

The archaeological karstic infill site of Galería Complex, located within the Atapuerca system (Spain), has produced a large faunal and archaeological record (Homo sp. aff. heidelbergensis fossils and Mode II lithic artefacts) belonging to the Middle Pleistocene. Extended-range luminescence dating techniques, namely post-infrared infrared stimulated luminescence (pIR-IR) dating of K-feldspars and thermally transferred optically stimulated luminescence (TT-OSL) dating of individual quartz grains, were applied to fossil-bearing sediments at Galería. The luminescence dating results are in good agreement with published chronologies derived using alternative radiometric dating methods (i.e., ESR and U-series dating of bracketing speleothems and combined ESR/U-series dating of herbivore teeth), as well as biochronology and palaeoenvironmental reconstructions inferred from proxy records (e.g., pollen data). For the majority of samples dated, however, the new luminescence ages are significantly (∼50%) younger than previously published polymineral thermoluminescence (TL) chronologies, suggesting that the latter may have overestimated the true burial age of the Galería deposits. The luminescence ages obtained indicate that the top of the basal sterile sands (GIb) at Galería have an age of up to ∼370 thousand years (ka), while the lowermost sub-unit containing Mode II Acheulean lithics (base of unit GIIa) was deposited during MIS 9 (mean age = 313±14 ka; n = 4). The overlying units GIIb-GIV, which contain the richest archaeopalaeontological remains, were deposited during late MIS 8 or early MIS 7 (∼240 ka). Galería Complex may be correlative with other Middle Pleistocene sites from Atapuerca, such as Gran Dolina level TD10 and unit TE19 from Sima del Elefante, but the lowermost archaeological horizons are ∼100 ka younger than the hominin-bearing clay breccias at the Sima de los Huesos site. Our results suggest that both pIR-IR and single-grain TT-OSL dating are suitable for resolving Middle Pleistocene chronologies for the Sierra de Atapuerca karstic infill sequences.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Archaeology*
  • Fossils*
  • Geologic Sediments / analysis
  • Herbivory / physiology*
  • Hominidae / anatomy & histology*
  • Hominidae / physiology
  • Humans
  • Luminescent Measurements
  • Paleontology*
  • Radiometric Dating / instrumentation
  • Radiometric Dating / methods*
  • Spain
  • Tooth / anatomy & histology
  • Tooth / physiology

Grants and funding

JMP, LJA and MD were financially supported by a grant (CGL2010-16821) from the Ministerio de Economía y Competitividad (Spain). MD was supported by a Marie Curie Reintegration grant (PIRG08-GA-2010-276810) within the 7th European Community Framework Programme. LA received additional support from an Australian Research Council (ARC) Future Fellowship grant (FT130100195). AIO has been supported by a postdoctoral grant from Juan de la Cierva Subprogram (JCI-2010-06792). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.