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

Demuro M, Arnold LJ, Parés JM, Pérez-González A, Ortega AI, Arsuaga JL, Bermúdez de Castro JM, Carbonell E - PLoS ONE (2014)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Institute for Photonics and Advanced Sensing, School of Chemistry and Physics, The University of Adelaide, Adelaide, Australia; Centro Nacional de Investigación sobre la Evolución Humana, Burgos, Spain.

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.

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Examples of single-grain TT-OSL De distributions plotted as histograms (logarithmic x-axis) and radial plots.Data is shown for selected Galería samples. See Figure S4 in File S1 for the De datasets of all other samples.
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pone-0110169-g005: Examples of single-grain TT-OSL De distributions plotted as histograms (logarithmic x-axis) and radial plots.Data is shown for selected Galería samples. See Figure S4 in File S1 for the De datasets of all other samples.

Mentions: The vast majority of Galería samples display similar single-grain TT-OSL De characteristics (Table 5). With the exception of AT10-2 and ATG10-7, all samples have overdispersion values below 25%, which is consistent with values obtained for ideal (well-bleached and unmixed) samples at the neighbouring Atapuerca site of Sima de los Huesos [47]. The log-transformed De distributions of these seven samples are normally distributed according to published skewness assessments [32] (Table 5, Figure 5 and Figure S4 in File S1) and they do not display pronounced ‘leading-edge’ shapes or elongated high dose tails. The De datasets are also well-represented by a single dose population, and most of the individual De values are consistent with the weighted mean burial dose estimate at 2σ (they fall within the grey shaded bands of the radial plots shown in Figures 5F, 5H and Figure S4 in File S1). These observations, together with the relatively high doses measured for these samples, indicate that any De scatter arising from partial bleaching is likely to be insignificant or effectively absent in these datasets. As such, we have used the weighted mean De values, calculated using the central age model (CAM) [81], to calculate representative burial dose estimates. The final single-grain TT-OSL De estimates for these seven Galería samples range between ∼510 Gy and ∼960 Gy (Table 5).


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

Demuro M, Arnold LJ, Parés JM, Pérez-González A, Ortega AI, Arsuaga JL, Bermúdez de Castro JM, Carbonell E - PLoS ONE (2014)

Examples of single-grain TT-OSL De distributions plotted as histograms (logarithmic x-axis) and radial plots.Data is shown for selected Galería samples. See Figure S4 in File S1 for the De datasets of all other samples.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4206284&req=5

pone-0110169-g005: Examples of single-grain TT-OSL De distributions plotted as histograms (logarithmic x-axis) and radial plots.Data is shown for selected Galería samples. See Figure S4 in File S1 for the De datasets of all other samples.
Mentions: The vast majority of Galería samples display similar single-grain TT-OSL De characteristics (Table 5). With the exception of AT10-2 and ATG10-7, all samples have overdispersion values below 25%, which is consistent with values obtained for ideal (well-bleached and unmixed) samples at the neighbouring Atapuerca site of Sima de los Huesos [47]. The log-transformed De distributions of these seven samples are normally distributed according to published skewness assessments [32] (Table 5, Figure 5 and Figure S4 in File S1) and they do not display pronounced ‘leading-edge’ shapes or elongated high dose tails. The De datasets are also well-represented by a single dose population, and most of the individual De values are consistent with the weighted mean burial dose estimate at 2σ (they fall within the grey shaded bands of the radial plots shown in Figures 5F, 5H and Figure S4 in File S1). These observations, together with the relatively high doses measured for these samples, indicate that any De scatter arising from partial bleaching is likely to be insignificant or effectively absent in these datasets. As such, we have used the weighted mean De values, calculated using the central age model (CAM) [81], to calculate representative burial dose estimates. The final single-grain TT-OSL De estimates for these seven Galería samples range between ∼510 Gy and ∼960 Gy (Table 5).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Institute for Photonics and Advanced Sensing, School of Chemistry and Physics, The University of Adelaide, Adelaide, Australia; Centro Nacional de Investigación sobre la Evolución Humana, Burgos, Spain.

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.

Show MeSH
Related in: MedlinePlus