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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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Published ages obtained using different dating methods (including this study) for the various allostratigraphic units and lithologic/archaeo-palaeontological levels at Galería.The data included here has been derived from combined ESR/U-series dating of teeth [15], TL and IRSL dating of sediment [14], ESR dating of calcite/speleothems [11], [104], U-series dating of calcite/speleothems [11], [15]. The numerical age estimates are shown against the Marine Oxygen Isotope curve record [94]. Two additional TL ages of 1340±170 ka (unit GIV) and 3000±1800 ka (unit GI) [14] are not shown on this plot as they lie beyond the x-axis limits (see Table 2 for a full summary of the dataset in [14]).
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pone-0110169-g007: Published ages obtained using different dating methods (including this study) for the various allostratigraphic units and lithologic/archaeo-palaeontological levels at Galería.The data included here has been derived from combined ESR/U-series dating of teeth [15], TL and IRSL dating of sediment [14], ESR dating of calcite/speleothems [11], [104], U-series dating of calcite/speleothems [11], [15]. The numerical age estimates are shown against the Marine Oxygen Isotope curve record [94]. Two additional TL ages of 1340±170 ka (unit GIV) and 3000±1800 ka (unit GI) [14] are not shown on this plot as they lie beyond the x-axis limits (see Table 2 for a full summary of the dataset in [14]).

Mentions: Table 2 and Figure 7 show the final TT-OSL and pIR-IR225 ages for the Galería Complex sequence. Both sets of extended-range luminescence ages are stratigraphically consistent and the replicate TT-OSL and pIR-IR225 ages of individual samples are in agreement at 1σ. The internal consistency of the two chronological datasets for the entire sequence provides support for the reliability of the TT-OSL and pIR-IR225 approaches adopted at this site. The TT-OSL age obtained for sample ATG10-4 suggests that the upper part of GI was deposited 374±32 ka. The two samples collected from the exposure in Zarpazos (ATZ10-3 and ATZ10-4), which are stratigraphically correlated as laying directly below GIIa, produced pIR-IR225 and TT-OSL ages of 310–322 ka. The four TT-OSL and pIR-IR225 ages for the lowest archaeological level (TG7) range between 284±16 ka and 335±20 ka (samples ATG10-9 and ATG10-10; Table 2), and produced a combined weighted mean age of 313±14 ka (n = 4) for the first appearance of lithic tools at Galería. Finally, the five samples from the overlying archaeological units (upper GIIa, GIIIa, GIIIb) and sterile GIV horizon (ATG10-8 to AT10-2) produced replicate pIR-IR225 and TT-OSL ages ranging between ∼220 and ∼260 ka. These ages are all statistically indistinguishable at 2σ (Figure 7), suggesting relatively rapid infilling of the Galería cavity over a timeframe that is comparable to our empirical error ranges. With the possible exception of the ATG10-9 pIR-IR225 age, all of the extended-range luminescence ages obtained in this study are in good agreement with the previously published ESR and U-series ages for speleothems [11], [13], [15] and combined ESR/U-series teeth ages [15] at either 1σ or 2σ (Table 2, Figure 7). The pIR-IR225 and TT-OSL ages are also in agreement with the TL and combined TL/IRSL ages obtained on unit GIIIb [14]. However, the other published TL ages for units GIIa, GIIIa and GIV are systematically older than our extended-range luminescence chronologies (Table 2, Figure 7).


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)

Published ages obtained using different dating methods (including this study) for the various allostratigraphic units and lithologic/archaeo-palaeontological levels at Galería.The data included here has been derived from combined ESR/U-series dating of teeth [15], TL and IRSL dating of sediment [14], ESR dating of calcite/speleothems [11], [104], U-series dating of calcite/speleothems [11], [15]. The numerical age estimates are shown against the Marine Oxygen Isotope curve record [94]. Two additional TL ages of 1340±170 ka (unit GIV) and 3000±1800 ka (unit GI) [14] are not shown on this plot as they lie beyond the x-axis limits (see Table 2 for a full summary of the dataset in [14]).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0110169-g007: Published ages obtained using different dating methods (including this study) for the various allostratigraphic units and lithologic/archaeo-palaeontological levels at Galería.The data included here has been derived from combined ESR/U-series dating of teeth [15], TL and IRSL dating of sediment [14], ESR dating of calcite/speleothems [11], [104], U-series dating of calcite/speleothems [11], [15]. The numerical age estimates are shown against the Marine Oxygen Isotope curve record [94]. Two additional TL ages of 1340±170 ka (unit GIV) and 3000±1800 ka (unit GI) [14] are not shown on this plot as they lie beyond the x-axis limits (see Table 2 for a full summary of the dataset in [14]).
Mentions: Table 2 and Figure 7 show the final TT-OSL and pIR-IR225 ages for the Galería Complex sequence. Both sets of extended-range luminescence ages are stratigraphically consistent and the replicate TT-OSL and pIR-IR225 ages of individual samples are in agreement at 1σ. The internal consistency of the two chronological datasets for the entire sequence provides support for the reliability of the TT-OSL and pIR-IR225 approaches adopted at this site. The TT-OSL age obtained for sample ATG10-4 suggests that the upper part of GI was deposited 374±32 ka. The two samples collected from the exposure in Zarpazos (ATZ10-3 and ATZ10-4), which are stratigraphically correlated as laying directly below GIIa, produced pIR-IR225 and TT-OSL ages of 310–322 ka. The four TT-OSL and pIR-IR225 ages for the lowest archaeological level (TG7) range between 284±16 ka and 335±20 ka (samples ATG10-9 and ATG10-10; Table 2), and produced a combined weighted mean age of 313±14 ka (n = 4) for the first appearance of lithic tools at Galería. Finally, the five samples from the overlying archaeological units (upper GIIa, GIIIa, GIIIb) and sterile GIV horizon (ATG10-8 to AT10-2) produced replicate pIR-IR225 and TT-OSL ages ranging between ∼220 and ∼260 ka. These ages are all statistically indistinguishable at 2σ (Figure 7), suggesting relatively rapid infilling of the Galería cavity over a timeframe that is comparable to our empirical error ranges. With the possible exception of the ATG10-9 pIR-IR225 age, all of the extended-range luminescence ages obtained in this study are in good agreement with the previously published ESR and U-series ages for speleothems [11], [13], [15] and combined ESR/U-series teeth ages [15] at either 1σ or 2σ (Table 2, Figure 7). The pIR-IR225 and TT-OSL ages are also in agreement with the TL and combined TL/IRSL ages obtained on unit GIIIb [14]. However, the other published TL ages for units GIIa, GIIIa and GIV are systematically older than our extended-range luminescence chronologies (Table 2, Figure 7).

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