Single-grain OSL dating of the Middle Palaeolithic site of Galería de las Estatuas, Atapuerca (Burgos, Spain)

Abstract

This study presents single-grain optically stimulated luminescence (OSL) chronologies for the archaeological site of Galería de las Estatuasthe first systematically excavated Middle Palaeolithic site within the karst system of the Sierra de Atapuerca archaeological complex, northern Spain. The single-grain OSL ages are compared with paired single-grain thermally transferred OSL (TT-OSL) dating results for a selection of samples in order to better assess quartz signal bleaching characteristics of endokarstic deposits preserved at Atapuerca. In total, seven luminescence dating samples were collected from four lithostratigraphic units exposed in two excavation pits (GE-I and GE-II). The single-grain OSL equivalent dose (D e) distributions are characterised by generally low overdispersion (20-30%), suggesting appropriate bleaching at deposition. The resultant single-grain OSL ages reveal that the sediment sequence and archaeological remains excavated in pit GE-I accumulated 80-112 ka, while the upper layers of excavation area GE-II were deposited 70-79 ka. The replicate single-grain TT-OSL ages are in agreement with the OSL chronologies at 2σ for three of the four samples investigated; although in all cases the TT-OSL ages were systematically older than their single-grain counterparts. Apparent TT-OSL residual doses (i.e., TT-OSL D e values in excess of their corresponding OSL D e values) of 9-65 Gy were observed for all samples. These excess TT-OSL D e values are generally low in comparison to the natural dose ranges of TT-OSL dating applications undertaken elsewhere in the Atapuerca karst system. The single-grain TT-OSL and OSL dating comparisons build on daylight bleaching experiments and modern analogue studies performed on other Atapuerca exogeneous infill deposits and suggest reasonable potential for TT-OSL signal resetting down to relatively low levels for at least some sediments preserved in the Atapuerca karstic cavities. The quartz single-grain OSL chronologies obtained in this study place the Middle Palaeolithic sequence of Galería de las Estatuas within marine isotope stage (MIS) 5 and the beginning of MIS 4, and provide firm evidence for human occupation of the Sierra de Atapuerca during a previously unreported time period.

Atapuerca Neanderthal landscape at Fuente Mudarra site in Burgos, Spain, during Marine Isotope Stages 5–3

“…Three caves dug in recent years, Galería de las Estatuas in Cueva Mayor (Arsuaga et al, 2017; Demuro et al, 2018; Pablos et al, 2019), Cueva Fantasma, and La Paredeja (see Fig. 1), complete the record from the late Pleistocene, which provides evidence of the presence of Homo neanderthalensis in Atapuerca.…”

Extinction of eastern Sahul megafauna coincides with sustained environmental deterioration

“…Quartz grains (212-250-μm diameter) from the 2015 and 2017 samples were purified at UA following standard laboratory procedures 83 , including the removal of the alpha-irradiated grain margins through treatment with 48% hydrofluoric acid (40 min) 84 . Equivalent dose (D e ) values were determined for single quartz grains using the single aliquot regenerative dose (SAR) procedure 85 and only accepted for dating purposes if they satisfied a series of quality assurance criteria 86 .…”

Unearthing Neanderthal population history using nuclear and mitochondrial DNA from cave sediments

“…S2). Almost 500 stone artifacts with clear Mousterian affinities, combined with single-grain optical dating of the associated sediments, indicate Neanderthal occupation from at least 113 ± 8 to 70 ± 5 ka ago [total uncertainty at 1s; (10,11)], yet only a single Neanderthal foot phalanx has been recovered (12) (fig. S3).…”