Optically stimulated luminescence and radiocarbon dating of sediments from Lop Nur (Lop Nor), China

Lop Nur is a playa lake occupying the lowest part of the Tarim Basin, northwestern China, and is now a desolate and barren region. In the past decades, the ages of the lacustrine sediments from the lake were determined mainly by radiocarbon dating on bulk sediment. In this study, both optically stimulated luminescence (OSL) and radiocarbon methods were used to date the sediments from a pit in the central part of the lake. The OSL ages obtained for ten samples range from 0.5 to 9.4 ka, and are in stratigraphic order except for one sample. The ¹⁴C ages obtained for twenty-two bulk sediment samples range from 5.8 to 30.2 cal ka BP with erratic distribution. Based on the comparison of ¹⁴C with OSL ages and their age-depth models, we argue that the OSL ages are relatively reliable. The disequilibria in the U decay chain for some samples are deduced from the comparison of the NAA and TSAC results. We suggest that the OSL dating technique should preferably be applied to the playa sediments from Lop Nur, but the disequilibria in the U decay chain should be considered in evaluating dose rates. Additionally, radiocarbon reservoir effects in lakes in western China are reviewed.     

Optically stimulated luminescence dating of sediments from the Yellow River terraces in Lanzhou: Tectonic and climatic implications

The stratigraphic chronology of Yellow River terraces was investigated and studied in Lanzhou Basin, western Chinese Loess Plateau. The optically stimulated luminescence (OSL) dating results show that terraces T₁, T₂ and T₃ formed at 8 ka, 20 ka and 70 ka, respectively. Lateral accretion of the riverbed facies gravel sediments occurred during interglacial periods while vertical aggradations of the terrace sediments deposited predominantly under cold and dry glacial period. A thick layer of aeolian loess with a basal age about 35 ka indicates a remarkable drop of air temperature and a dry, cold climate. The temporal correlation between terrace formation and tectonic movement has not yet been established in this research, but the stratigraphic chronology of the terrace sections provides the timing of the terrace formation, the incision rate of the Yellow River, and the slip rate of the fault horizon.     

Infrared stimulated luminescence and radiofluorescence dating of aeolian sediments from Hungary

Anomalous fading of the infrared stimulated luminescence (IRSL) signal from the polymineral fine-grain and K-feldspar fractions of aeolian sediments from Hungary has been studied. The samples in this study have previously been dated using the multiple aliquot additive dose (MAAD) protocol to measure the IRSL signal. The IRSL measurements using MAAD were conducted ～4 weeks after the irradiation, making it difficult to assess to what extent these age estimates were affected by anomalous fading. In this study, equivalent doses were obtained using the single aliquot regenerative dose (SAR) protocol. The fading rate for each sample was calculated using the different IRSL components and different parts of the decay curve. For each sample, the middle part of the decay curve always showed a lower fading rate than the initial part of the decay curve. The difference between the fading rates for different parts of the decay curve was greater for the K-feldspars than for the polymineral fine grains. Fading corrected ages were calculated by integrating both the initial and the middle part of the decay curve. These ages were compared with optically stimulated luminescence (OSL) ages from quartz, infrared radiofluorescence (IR-RF) ages obtained from K-feldspars and also with independent ages, provided by radiocarbon dating of shells and charcoal, and uranium-series dating of travertine.     

Optically stimulated luminescence dating of young (<500 years old) sediments: Testing estimates of burial dose

The reliability of single-grain optically stimulated luminescence (OSL) dating of young (<500 years old) samples is assessed by examining the results of 166 single-grain OSL analyses of Australian alluvial, lacustrine, estuarine, coastal and marine sediment samples. All samples have been analysed using the modified SAR protocol of Olley et al. [2004b. Optical dating of Holocene sediments from a variety of geomorphic settings using single grains of quartz. Geomorphology 60, 337–358], with burial doses (D_b) calculated by fitting a single Gaussian curve to the peak of a multi-Gaussian summed probability distribution (PDF_Gaussian). The near-equivalence of this approach to currently accepted methods of palaeodose estimation – namely the minimum age and central age models of Galbraith et al. [1999. Optical dating of single and multiple grains of quartz from Jinmium rock shelter, northern Australia: part I, experimental design and statistical models. Archaeometry 41, 339–364] – is demonstrated. Considered as a whole, OSL ages calculated using the PDF_Gaussian D_b determination method are consistent with other chronometric, geomorphological, botanical and historical indicators of depositional age, while four alternative (previously published) methods are generally less reliable when applied to the samples analysed here. The single-grain data from 12 samples of known age (reported by Olley et al. [2004b. Optical dating of Holocene sediments from a variety of geomorphic settings using single grains of quartz. Geomorphology 60, 337–358]) are re-analysed using the PDF_Gaussian approach, with all but one yielding a D_b consistent with the independently known age. Examples of luminescence data (dose recovery tests, preheat plateaux, continuous-wave and linear-modulated OSL, growth curves, single-grain dose distributions) are provided that together indicate the suitability of Australian quartz for dating young sediments.     

Optically stimulated luminescence dating of sublittoral and intertidal sediments from Dubai, UAE: Radioactive disequilibria in the uranium decay series

Shallow marine and intertidal shell rich sediments from the low coastal plain of Dubai were dated by optically stimulated luminescence. Combined high-resolution gamma spectrometry and ICP–MS analyses revealed significant disequilibria in the ²³⁸U decay series. Time dependent dose rates were modelled for two scenarios including a closed system and an open system with linear U and Ra uptake. OSL ages that were calculated using the linear uptake model are in good agreement with archaeological evidence and radiocarbon datings on shells and wood. The presented results illustrate that luminescence-dating techniques are suitable to set up a chronostratigraphic frame for calcareous coastal environments if an appropriate model is applied to consider the influence of radioactive disequilibria and time dependent dose rates. A comprehensive radionuclide analysis of the sediments is thought necessary to perform geochemically supported dose rate simulations.     

Radiocarbon and optically stimulated luminescence dating of sediments from Lake Karakul,Tajikistan

Lake Karakul in the eastern Pamirs is a large and closed-basin lake in a partly glaciated catchment. Two parallel sediment cores were collected from 12 m water depth. The cores were correlated using XRF analysis and dated using radiocarbon and OSL techniques. The age results of the two dating methods are generally in agreement. The correlated composite core of 12.26 m length represents continuous accumulation of sediments in the lake basin since 31 ka. The lake reservoir effect (LRE) remained relatively constant over this period. High sediment accumulation rates (SedARs) were recorded before 23 ka and after 6.5 ka. The relatively close position of the coring location near the eastern shore of the lake implies that high SedARs resulted from low lake levels. Thus, high SedARs and lower lake levels before 23 ka probably reflect cold and dry climate conditions that inhibited the arrival of moist air at high elevation in the eastern Pamirs. Low lake levels after 6.5 ka were probably caused by declining temperatures after the warmer early Holocene, which had caused a reduction in water resources stored as snow, ice and frozen ground in the catchment. Low SedARs during 23–6.5 ka suggest increased lake levels in Lake Karakul. A short-lived increase of SedARs at 15 ka probably corresponds to the rapid melting of glaciers in the Karakul catchment during the Greenland Interstadial 1e, shortly after glaciers in the catchment had reached their maximum extents. The sediment cores from Lake Karakul represent an important climate archive with robust chronology for the last glacial–interglacial cycle from Central Asia.     

Optically stimulated luminescence dating of loess in South-Eastern China using quartz and polymineral fine grains

Loess deposits distributed in southeastern China play an important role for paleoclimate reconstruction of the subtropical regions. These loess-paleosol deposits are mainly spread within the middle and lower reaches of the Yangtze River as well as in the drainage area of the Huai River. The ages of loess paleosol sequences that are distributed along the Huai River are not well constrained. In this study, the standard single-aliquot regenerative dose (SAR) optically stimulated luminescence (OSL) protocol and two elevated temperature post infrared-infrared stimulated luminescence SAR protocols (pIRIR₂₂₅ and pIRIR₂₉₀) were applied on 4–11 μm quartz and polymineral fine grains, respectively, in order to obtain the first numerical luminescence chronology for a loess-paleosol sequence in northern Jiangsu Province. Our results show a good agreement between quartz SAR-OSL and polymineral pIRIR ages up to ~70 ka. These findings confirm that Xiashu loess accumulated during the Last Glaciation. For samples older than this, the ages increasingly deviate with depth. Fine quartz ages beyond 70 ka are interpreted as underestimates, as previous studies reported that quartz ages >70 ka from various sedimentary origins worldwide may underestimate even if they pass rejection criteria and dose recovery tests. On the other hand, the pIRIR ages are most likely overestimating the true depositional ages as indicated by the results of dose recovery tests, where a 30–60% overestimation of the recovered dose is reported for values larger than ~400 Gy. The overestimation of pIRIR protocols was also confirmed by the results obtained when large beta doses were added on top of the natural accrued dose. Moreover, our dating results suggest that L1/S1 transition (corresponding to MIS 5/4 boundary) occurred much higher in the stratigraphic sequence than may have been interpreted from the magnetic susceptibility enhancement. This inconsistency can be assigned to invalidity of magnetic susceptibility as a chronostratigraphical proxy due to ferrimagnetic minerals dissolution or transformation during paedogenesis processes in this humid subtropical region in the southeastern China.     

Optically stimulated luminescence dating of a Holocene beach ridge plain in Northern Jutland, Denmark

This study presents results from 20 optically stimulated luminescence (OSL) ages from one of the world's largest beach ridge plains, the Jerup beach ridge plain at the base of the Skagen Spit in the northernmost part of Jutland, Denmark. The OSL ages were obtained using quartz and a SAR protocol, and used to establish a chronology for the beach ridge plain and for the underlying coastal plain. The accuracy of the chronology is tested both by laboratory tests (recuperation, recycling ratio and dose recovery) and by comparison with independent age controls, e.g. previously reported radiocarbon dates, map sources, anecdotal evidence and settlement names. It is concluded that the OSL signals are internally consistent, and that the derived OSL ages are in good agreement with a large range of independent age controls. The ridge plain is shown to cover a time span from 1000 to 2700 years ago; this chronology is more detailed and precise than those previously available, and gives an average beach ridge formation rate of 15 yr/ridge and an average lateral migration rate of 2.0 m/yr. This study adds to the growing knowledge that OSL dating has a large potential for establishing detailed and precise chronologies in coastal marine sediments, including beach ridges.     

Single grain optically stimulated luminescence dating of glacial sediments from the Baiyu Valley,southeastern Tibet

The Qinghai-Tibetan Plateau is an important area for the study of Quaternary glaciation. Optically stimulated luminescence (OSL) dating has the potential to contribute to the chronology of glaciation in this region, but it is important to assess the accuracy of OSL dating of these glacial sediments. In this study, single grain quartz OSL signals are examined for five glacial samples collected from the moraines outside the Baiyu Valley, southeastern Tibet. The quartz grains exhibit poor luminescence characteristics, with a small proportion of grains passing the screening criteria. Grains which pass the screening criteria have relatively low signal intensity, leading to D_e values with large uncertainties. MAM and CAM were used to determine D_e values for these samples. The OSL ages are consistent with the sequence of events derived from the geomorphological relationship of the samples, and also with previous published radiocarbon ages. However, it is more difficult to reconcile the OSL ages and the terrestrial cosmogenic nuclide (TCN) ¹⁰Be ages. Analysis of both single grain quartz OSL data and TCN ¹⁰Be data is complex in this area. Further work is required to increase confidence in the OSL ages generated for the glacial sediments from this region.     

Optically stimulated luminescence dating of aeolian sand in the Otindag dune field and Holocene climate change

The dune system in Otindag sand field of northern China is sensitive to climate change, where effective moisture and related vegetation cover play a controlling role for dune activity and stability. Therefore, aeolian deposits may be an archive of past environmental changes, possibly at the millennial scale, but previous studies on this topic have rarely been reported. In this study, thirty-five optically stimulated luminescence (OSL) ages of ten representative sand-paleosol profiles in Otindag sand field are ob-tained, and these ages provide a relatively complete and well-dated chronology for wet and dry varia-tions in Holocene. The results indicate that widespread dune mobilization occurred from 9.9 to 8.2 ka, suggesting a dry early Holocene climate. The dunes were mainly stabilized between 8.0 and 2.7 ka, implying a relatively wet climate, although there were short-term penetrations of dune activity during this wet period. After ~2.3 ka, the region became dry again, as inferred from widespread dune activity. The "8.2 ka" cold event and the Little Ice Age climatic deterioration are detected on the basis of the dune records and OSL ages. During the Medieval Warm Period and the Sui-Tang Warm Period (570-770 AD), climate in Otindag sand field was relatively humid and the vegetation was denser, and the sand dunes were stabilized again. These aeolian records may indicate climate changes at millennial time scale during Holocene, and these climatic changes may be the teleconnection to the climate changes elsewhere in the world.     

Violet stimulated luminescence as an alternative for dating complex colluvial sediments in the Atacama Desert

Luminescence dating has become a key tool in studies of the Quaternary. The typically stable luminescence response of quartz grains and the absence of a significant internal dose, make quartz minerals the preferred dosimeter for monitoring the burial dose in sediments. Unfortunately, the reliability of conventional OSL (optically stimulated luminescence) dating, based on blue stimulation, can be compromised when the luminescence decay is not dominated by a rapidly decaying and stable part of the luminescence signal (i.e. the fast component). On the other hand, standard methods in luminescence dating are limited to ages of a few hundred kiloyears. In this study, violet stimulated luminescence (VSL) has been used as a means to overcome both problems, applied to a series of colluvial deposits in the Atacama Desert, Chile. Quartz from this region, characterized by poor blue-OSL response, showed a reproducible and stable VSL signal capable of recovering given doses up to ∼500 Gy and a saturation dose twice as high as conventional OSL. The VSL response from these samples has been studied in detail and the estimated ages have been compared with an already established chronology for the same site, based on IRSL of potassium feldspar single grains. Results agree for the dose range of the profile studied, ∼100–250 Gy, equivalent to ages of 29–79 ka confirming the suitability of VSL for dating sedimentary quartz with unreliable blue-OSL response and to extend the age range of conventional OSL dating.     

Evaluating isothermal thermoluminescence and thermally transferred optically stimulated luminescence for dating of Pleistocene sediments in Amazonia

The paleogeography of Amazonia lowlands during the Pleistocene remains hampered by the lack of reliable absolute ages to constrain sediment deposition in the hundred thousand to few million years timescales. Optically stimulated luminescence (OSL) dating applied to quartz has provided important chronological control for late Quaternary sediments, but the method is limited to the last ∼150 ka. In order to extend the age range of luminescence dating, new signals from quartz have been investigated. This study tested the application of isothermal thermoluminescence (ITL) and thermally transferred optically stimulated luminescence (TT-OSL) signals of quartz for dating of fluvial terraces from eastern Amazonia. ITL and TT-OSL signals measured in a modern fluvial sediment sample have shown small residual doses (4 and 16 Gy), suggesting adequate bleached sediments for the target dose range (>150 Gy). This sample responded well to dose recovery test, which showed that the ITL and TT-OSL signals grow to higher doses compared to the doses estimated by the conventional OSL signal. The ITL signal saturated for doses significantly lower than doses reported in the literature. Most dating samples were beyond the ITL saturation doses and only TT-OSL signals were suitable to estimate equivalent doses. Burial ages ranging from 107 to 340 ka were estimated for the fluvial terraces in the lower Xingu River. The main ages uncertainties are related to dose rate changes through time. Despite the uncertainties, these ages should indicate a higher channel base level during the Middle Pleistocene followed by channel incision, possibly due to episodes of increased precipitation in the Xingu watershed.     

Optically stimulated luminescence dating of Ocean Drilling Program core 658B: Complications arising from authigenic uranium uptake and lateral sediment movement

Ocean Drilling Program Site 658 lies under the North African summer dust plume, and ought to be an ideal target for optically stimulated luminescence (OSL) dating, since the main clastic input is far-travelled Saharan dust. However, OSL ages for coarse silt-sized quartz (40–63 μm) are systematically lower than independent age estimates when dose rates are calculated using a model which assumes detrital ²³⁸U, ²³²Th and ⁴⁰K and excess ²³⁰Th and ²³¹Pa. Ages which are in good agreement with independent age control are obtained from the coarse silt samples when a correction for authigenic uranium uptake is incorporated into the dose rate model. Authigenic uranium uptake occurs under reducing conditions, which are common at the sediment–water interface, and some degree of authigenic uranium correction may be required for most marine sediments. Using this revised dose rate model, ages produced using fine silt-sized quartz (4–11 μm) are up to 100% older than both independent and coarse silt ages. In addition, the fine silt ages show a consistent pattern of age decrease with depth over 1.5 m of core. ²³⁰Th data from Site 658 indicate that this site receives 3 times more sediment laterally than vertically. It is concluded that the fine silt at Site 658 contains a substantial reworked component, making it unsuitable for dating. Conversely the coarse silt fraction, which settles through water at ∼40 times the rate of fine silt, appears to be derived from dust input over the site at the time of deposition. Since prominent nepheloid (cloudy) layers occur in various deep ocean basins, and the material suspended in these layers often consists of reworked fine silt-sized sediments, coarser material should be dated where possible.     

The effect of weathering on optically stimulated luminescence dating

Optically stimulated luminescence (OSL) dating was applied to quartz samples recovered from the gravel sediments of deformed marine terrace at the Suryum site, southeastern Korea, but has yielded stratigraphically inconsistent ages. Micromorphological, chemical, and mineralogical analyses of the gravels indicate the possible influence of chemical weathering on the apparent OSL ages. In the course of weathering after emerging from beach environments, originally permeable gravels underwent infilling by halloysite-rich clays in their voids, export and import of radioactive elements, and loss of mechanical strength with the creation of a porosity within pebbles. Calculation based on the evolution of the weathering profile showed a severe fluctuation of dose rate caused by the change of water content and radioactive element concentrations. Samples recovered from the weathering profile inevitably include quartz grains derived from mechanically weakened pebbles or illuviated from the upper layer, making it difficult to determine the equivalent dose (D_e) values of exclusively depositional quartz sands. Quantitative evaluation of the change of fabric and chemistry of the sediments on the basis of pedologic insight significantly aids in the derivation of OSL ages consistent with geomorphology and other independent age controls.     

Recuperated optically stimulated luminescence dating of middle-size quartz grains from the Palaeolithic site of Bonneval (Eure-et-Loir,France)

The site of Bonneval (France) exhibits a 6 m thick stratigraphical sequence in which Middle and Lower Palaeolithic artefacts were discovered. The stratigraphy of the site consists of an alternation of loess-like silt layers deposited along glacial stages, and paleosoil horizons corresponding to the vegetal stabilization of the area during interglacials. These layers hence provide past environmental informations and can be used as stratigraphical markers and compared with well dated sequences of Northern France. Eight sediment samples from this Middle and Upper Pleistocene sequence were dated using the recuperated optically stimulated luminescence (Re-OSL) signal of quartz grains. The middle-size fraction (40–63 μm) shows a good reproducibility of the OSL signals which allows the application of a multiple-aliquot additive-dose approach for D_e determination. For all samples, the growth curves are linear up to an accumulated dose of 3000 Gy. The Re-OSL ages range from ～100 to ～450 ka and are in good agreement with the independent chronological information; they establish when handaxe industries have been made during the Middle and Upper Pleistocene in the Paris Basin.     

Testing the potential of luminescence dating of high-alpine lake sediments

The potential of luminescence dating of high-alpine lacustrine sediments is tested on samples taken from three high-altitude moraine-bounded lakes in the Swiss Alps. Independent age control is provided by radiocarbon ages and detailed palynological data in all cases. All samples show good luminescence characteristics (no thermal transfer, good dose recovery and recycling), but two samples show rather low quartz signals. Radioactive disequilibria in the uranium decay chain observed in one sample are accounted for by using a dynamic modelling approach. Because all cores had largely dried out and water content had not been measured after sampling, we developed a modern limnological approach to retrospectively establish palaeo-water content. Applying average water content values from a dataset of modern sediments with similar characteristics to the samples investigated here we obtained ages that match the independent age control. Whereas the low-signal quartz separates consistently underestimate these ages, the polymineral samples more accurately match them, do not suffer from anomalous fading and are thus considered reliable. This study demonstrates for the first time that applying luminescence dating to high-alpine, ice-proximal lacustrine sediments is a promising avenue to obtain a chronology for such depositional environments.     

Applying SAR-IRSL methodology for dating fine-grained sediments from Lake El’gygytgyn, north-eastern Siberia

Lake El’gygytgyn is situated in a 3.6 Ma old impact crater in north-eastern Siberia and probably represents one of the most complete archives of Arctic climate change. Investigated here is the potential of infra-red stimulated luminescence (IRSL) using the single-aliquot regenerative-dose (SAR) approach for dating sediments from this lake. Independent age control is available from a published age model of a parallel core that is based on tuning sediment proxies with regional insolation and the results of previous multiple aliquot IRSL dating. Although the site is located within volcanic bedrock, anomalous fading seems to have little effect on the calculated ages. The modelled water content for the entire time of burial is seen as the most prominent uncertainty at this particular site. Despite these potential error sources, SAR-IRSL ages are in acceptable agreement with the given timeframe and clearly point to the possibility to establish independent chronologies at this site up to at least 400,000 years.     

A Bayesian central equivalent dose model for optically stimulated luminescence dating

In this study, we propose and implement a Bayesian model to estimate a central equivalent dose from a set of luminescence measurements. This model is based on assumptions similar to the ones used in the standard statistical pipeline (typically implemented in the Analyst software followed by a subsequent central equivalent dose analysis) but tackles some of its main limitations. More specifically, it consists of a three-stage hierarchical model that has two main advantages over the standard approach: first, it avoids the introduction of auxiliary variables (typically mean and variance), at each step of the inference process, which are likely to fail to characterise the distributions of interest; second, it ensures a homogeneous and consistent inference with respect to the overall model and data. As a Bayesian model, our model requires the specification of prior distributions; we discuss such informative and non-informative distributions and check the relevance of our choices on synthetic data. Then, we use data derived from Single Aliquot and Regenerative (SAR) dose measurements performed on single grains from laboratory-bleached and dosed samples. The results show that our Bayesian approach offers a promising alternative to the standard one. Finally, we conclude by stressing that, relying on a Bayesian hierarchical model, our approach could be modified to incorporate additional information (e.g. stratigraphic constraints) that is difficult to formalise properly with the existing approaches.     

Optically stimulated luminescence dating of hearths from the Fazzan Basin,Libya: A tool for determining the timing and pattern of Holocene occupation of the Sahara

Circular concentrations of burned stone fragments are widespread in the Sahara, and are generally interpreted as ancient hearths. These hearths provide a rich resource for reconstructing the pattern and timing of Holocene human occupation of North African drylands. However, this resource has not been fully exploited since only 5% of hearths contain dateable carbon, and collection of this carbon frequently results in the destruction of the hearth. Previous research indicates that anthropogenic firing empties the optically stimulated luminescence (OSL) source traps of quartz grains within hearth rocks. Consequently, the quartz OSL signal should provide a means for determining the time elapsed since last firing of Saharan hearths. To test the applicability of this approach to Saharan hearths, samples were collected from a site in the Fazzan Basin, and analysed using single-grain OSL. Equivalent dose–depth profiles through hearth rocks demonstrate that they are sufficiently opaque to preserve a record of ancient firing. Comparison with unfired parent material indicates that anthropogenic firing of hearth rocks was sufficient to empty the OSL source traps. The OSL ages for hearth rocks are internally consistent and suggest use around 8 ka. Our study demonstrates that OSL dating is a viable tool for determining the timing and pattern of Holocene occupation of the Sahara.     

Optically stimulated luminescence of amorphous/microcrystalline SiO2 (silex): Basic investigations and potential in archeological dosimetry

Unlike the well-studied optically stimulated luminescence (OSL) signal of (macrocrystalline) quartz, not much is known about OSL from natural amorphous and microcrystalline silicon dioxide. These materials – generally termed “silex” – were widely used for prehistoric tool production, and thermoluminescence (TL) is routinely applied do date the firing event of heated specimens. This study presents data on basic OSL characteristics of silex such as signal composition and component-resolved thermal stability as well as the applicability of OSL for dating of burnt lithic tools.Fitting of LM-OSL curves yielded similar components (mostly five) as observed for quartz, with the photoionization cross-sections being in the same order of magnitude for both materials. Three different methods (LM-OSL pulse annealing, short-shine pulse annealing as well as the varying heating rate method) were applied to study the thermal stability of components and allowed calculating trap parameters E and s, and hence the electron retention lifetime. Only the most light-sensitive (“fast-like”) component proved to be of sufficient thermal stability for dating applications, as evidenced from coherent experimental results. All other components already diminished at preheating temperatures > 200 °C. Pulse annealing measurements further indicate that electron populations sampled by OSL and those responsible for the ca. 380 °C TL-“dating peak” are not identical. Dose recovery tests applying an OSL-SAR protocol with “hot bleach” in between the regeneration cycles showed good reproducibility of a known dose if only the initial OSL signal (ca. 0–0.5 s at 90% LED power) is used. Finally, obtained OSL-SAR and TL ages based on the blue TL emission are in agreement within errors for two Middle Paleolithic archeological samples showing a “fast-like” component. These results verify the experimental findings of sufficient long-term stability of the initial OSL signal. Since not all silex specimens deliver a bright and stable OSL signal, optical ages of suitable samples may serve as an additional internal check for the paleodose estimate rather than substituting TL as a standard technique for dating of heated silex.