rss_2.0Geochronometria FeedSciendo RSS Feed for Geochronometriahttps://sciendo.com/journal/GEOCHRhttps://www.sciendo.comGeochronometria Feedhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/649c2e7d8e9d9f5e34493d2c/cover-image.jpghttps://sciendo.com/journal/GEOCHR140216Electron Spin Resonance Dating of the Quaternary Fluvial Terrace System of the Upper Han River, Central Chinahttps://sciendo.com/article/10.2478/geochr-2023-0013<abstract> <title style='display:none'>Abstract</title> <p>The geomorphology of the upper Han River, which is located in the southern Qinling Mountains (central China) and within the northern subtropical monsoon climate zone, contains abundant information on tectonic and climatic changes. Many Paleolithic sites are preserved in the Quaternary terraces in this region, making it an ideal area for studying both geomorphology and ancient human activity. However, owing to limitations in dating methods, the formation ages of the higher terraces T3–T5 of the upper Han River remain unclear. We collected 11 samples of sediment from the higher Quaternary terraces of Wufeng, Qingqu and the Yunyang Basin for electron spin resonance (ESR) dating of quartz grains. Results show that the formation ages of terraces T3, T4 and T5 are 422–401 ka, 627–621 ka and 1129–1099 ka, respectively. Integrating this information with the timings of documented climatic transitions and the history of regional uplift, we propose that the upper Han River terraces formed in response to the combined effects of climatic transition and tectonic uplift.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00132024-02-29T00:00:00.000+00:00Chronostratigraphy of the Periglacial Loess-Paleosol Sequence in Zaprężyn, SW Polandhttps://sciendo.com/article/10.2478/geochr-2023-0014<abstract> <title style='display:none'>Abstract</title> <p>Loess-paleosol sequences (LPS) are an exceptional source of palaeoclimate data constituting an indirect record of changing environmental and climatic conditions that prevailed during loess deposition and early diagenesis. The Zaprężyn LPS (17°11′52″E, 51°14′44″N) is situated in the southern morphological edge of the Trzebnica Hills. This sequence provides an opportunity to reconstruct past climate conditions in this part of SW Poland. In this work, we used two sets of optically stimulated luminescence (OSL) dating from the Gliwice and Bayreuth laboratory to establish a chronological framework for this profile. The results of <sup>14</sup>C accelerator mass spectrometry (AMS) dating were also used. The dating results are accompanied by detailed analyses of grain-size distribution and colour. The applied methodology allowed us to distinguish four litho-pedotratigraphic units: modern soil S0, L1LL1 loess unit, L1LL2 loess unit and fossil S1 soil. The OSL dating results indicate an unconformity representing a time interval &gt;30 ka between the L1LL1 and L1LL2 units. This unconformity explains the lack of a L1SS1 soil unit. In Zaprężyn LPS, the presence of the ice wedge pseudomorph in L1LL2 loess unit was recorded. Ice wedge pseudomorph approves the presens the permafrost conditions during the Lower Plenivistulian in Trzebnica Hills.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00142024-02-18T00:00:00.000+00:00Investigation of Trees' Sensitivity to Drought: A Case Study in the Opole Region, Polandhttps://sciendo.com/article/10.2478/geochr-2023-0011<abstract> <title style='display:none'>Abstract</title> <p><italic>Pinus sylvestris</italic> L. is the most common tree species growing in Poland. Trees of this species are considered to be resistant to difficult meteorological conditions; however, in the past decades, many of them have died and been cut down by foresters. The measurements of the annual tree ring width can provide information on how trees respond to drought events. This study aimed to investigate the potential differences between healthy and declining trees (identified as trees to be cut down by foresters). For this purpose, we collected samples of five trees from each group and analysed them using dendrochronological and quantitative wood anatomy approaches. We measured ring width index (RWI) chronologies for healthy and declining trees and compared them with climate data. Additionally, we compared some anatomical features of trees from both groups as cell wall thickness (CWT) and lumen area (LA). The conducted analyses showed significant differences between healthy and declining trees. In particular, declining trees were characterised by lower RWI, LA and CWT values, especially in the past 20 years, and showed greater sensitivity to changes in temperature and humidity than healthy trees.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00112024-02-18T00:00:00.000+00:00δC and Intrinsic Water Use Efficiency for Trees in Various Health Conditions – Case Study for Świerklaniec Forest District Forest Districthttps://sciendo.com/article/10.2478/geochr-2023-0010<abstract> <title style='display:none'>Abstract</title> <p>The study included a comparative analysis of two <italic>Pinus sylvestris</italic> L. trees growing next to each other, but in a different health condition, and the reference trees growing in the same area in Poland. The declining tree, although it was a more difficult research material, was subjected to the same analyses as healthy trees, including: creating a ring width index (RWI) record, a δ<sup>13</sup>C record, an intrinsic water use efficiency (iWUE) record and checking for the following correlations: δ<sup>13</sup>C-temperature, δ<sup>13</sup>C-precipitation, δ<sup>13</sup>C-SO<sub>2</sub>, and iWUE-SO<sub>2</sub>. Our study found that trees with different health conditions may have comparable growth patterns, but different carbon isotopic compositions and iWUE. Differences between individual trees were also observed in sensitivity to changes in temperature and SO<sub>2</sub> emissions. The declining tree showed more significant correlations with summer temperatures, than the healthy tree and the reference trees, where significant correlations occurred in single months. Only in the instance of the declining tree, correlations were found between δ<sup>13</sup>C and SO<sub>2</sub>. iWUE of all trees did not show sensitivity to SO<sub>2</sub> emitted in high concentrations; however, we observed the sensitivity of iWUE from the reference trees to low SO<sub>2</sub> concentrations.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00102024-01-27T00:00:00.000+00:00Age and Origin of Fluvial Deposits in the Vistula River Valley Near Tarnobrzeg (Sandomierz Basin, Poland): Insights from Sediment Dating and Analysishttps://sciendo.com/article/10.2478/geochr-2023-0009<abstract> <title style='display:none'>Abstract</title> <p>The present research aimed to determine the age and origin of a 4-m sequence of fluvial deposits located in Siedleszczany on the western side of the Tarnobrzeg Monadnock in the Vistula River valley. Initially, these deposits were thought to be sediments of the overflood (Vistulian) terrace. The study revealed that the sand deposits are relatively young Late Holocene sediments, spanning from the 8th century AD to the 15th–16th centuries AD, and the organic material originated from erosion of older Holocene deposits of various ages. This finding was supported by palynological analysis, which identified, besides Holocene pollen grains, also those from Late Glacial and other Quaternary periods, and even from pre-Quaternary ones. Extreme floods in the Vistula valley may be specified as the origin of the sandy sediments in Siedleszczany. Similar large floods occurred in the past when ice jams blocked the main riverbed, leading to the formation of overflow channels. These floods caused rapid erosion of the flood-plain and deposition of sandy sediments in the sheltered marginal areas of the valley, away from high-velocity flood flows. As a result, the fluvial deposits in Siedleszczany, in the Vistula valley, resemble palaeoflood slackwater deposits observed in various regions worldwide.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00092023-12-31T00:00:00.000+00:00The Role and Frequency of Wildfires in the Shaping of the Late Glacial Inland Dunes – A Case Study from the Korzeniew Site (Central Poland)https://sciendo.com/article/10.2478/geochr-2023-0006<abstract> <title style='display:none'>Abstract</title> <p>The study examines sedimentology, stratigraphy, and the impact of wildfires on aeolian and soil processes during the Late Glacial Termination in the Korzeniew site, central Poland. The site, within a parabolic dune's central and lee-slope area, presents stacked aeolian sand units intermixed with six charcoal-enriched palaeosols. Thirteen optically stimulated luminescence (OSL) dates on quartz and six radiocarbon dates establish the chronological framework, dating deposition processes. Initial aeolian sand deposition occurred towards the Late Pleniglacial's end. Climate amelioration during the Bølling interstadial led to permafrost thaw and gleyic soil formation, later overlain by migrating parabolic dunes from the older Allerød interstadial. Wildfires, influenced by vegetation cover, deposited charcoals on the dune's lee slope. These charcoals underwent pedogenic reworking amid episodes of aeolian sand deposition during the Allerød interstadial and Younger Dryas, stabilizing in the earliest Holocene. Wildfires significantly impacted local vegetation development and aeolian activity. Despite the warmth of the Allerød interstadial, increased fires correlated with expanding pine forests and their heightened fire susceptibility. Short-term climate shifts likely destabilized vegetation, fostering fire occurrences during the Allerød interstadial.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00062023-12-31T00:00:00.000+00:00Accounting for Overcounting Induced by Rn Contamination in C Measurements Performed with Liquid Scintillation Countinghttps://sciendo.com/article/10.2478/geochr-2023-0007<abstract> <title style='display:none'>Abstract</title> <p>This research paper introduces a methodology for estimating overcounting resulting from uranium series radionuclides, with a specific focus on <sup>222</sup>Rn contamination. The method is demonstrated using the Quantulus 1220<sup>TM</sup> spectrometer. Exponential fitting is employed for the calculations, utilizing a custom algorithm developed in MATLAB<sup>®</sup> R2022b. The proposed method allows for the determination of the sample count rate correction, F<sup>14</sup>C and radiocarbon age without the need for additional chemical treatment or specialized electronics during liquid scintillation counting (LSC) measurements with the Quantulus 1220<sup>TM</sup> spectrometer. However, the method does have certain limitations. It requires a significant number of cycles and extended measurement time per cycle, but it can be applied to samples with significant <sup>222</sup>Rn contamination that require rapid <sup>14</sup>C analysis.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00072023-12-15T00:00:00.000+00:00Development of Chronology for Historical Mining Shaft Remains in the Vicinity of Tarnowskie Góry Based on Radiocarbon, Luminescence and Dendrochronological Datinghttps://sciendo.com/article/10.2478/geochr-2023-0004<abstract> <title style='display:none'>Abstract</title> <p>This study focused on determining the age of sediments found in the remains of historical mining in the post-exploitation field in Tarnowskie Góry, Poland. The limited historical sources indicated that lead ore and silver were mined there from the 12<sup>th</sup> to 20<sup>th</sup> centuries. The research utilised radiocarbon dating, optically stimulated luminescence (OSL) and fallout radioisotopes analysis to establish a chronology of the mining remains. Excavations were conducted on three historical mining shafts. In one of them, remains of old construction wood were found. Radiocarbon dating yielded 12 results, with the majority falling within the range of 1435 cal AD to 1645 cal AD. Two results were significantly older and covered the period of the beginnings of the Polish State. OSL dating provided results ranging from 2.5 ka BP to 216 ka BP, a time range much older than that indicated by radiocarbon dates. The OSL ages were found to be greatly overestimated, indicating that the luminescence signal was not reset during the redeposition of sediments. While the obtained results provided a preliminary chronology of the study site, further detailed research, especially regarding the older samples, is necessary to enhance our understanding of the mining history in the area.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00042023-11-22T00:00:00.000+00:00Testing the Applicability of Quartz and Feldspar for Luminescence Dating of Pleistocene Alluvial Sediments in the Tatra Mountain Foothills, Slovakiahttps://sciendo.com/article/10.2478/geochr-2023-0002<abstract> <title style='display:none'>Abstract</title> <p>Luminescence dating is a widely used method in combination with sedimentological analysis for reconstructing the landscape development of the Quaternary period. In this study, quartz and K-feldspar measurements were used to evaluate the luminescence characteristics with the aim of dating the deposits. The sediments were sampled from an abandoned gravel pit in the Biely Váh valley and eight sites in the lower part of the Velická dolina valley, High Tatra Mountains, Slovakia. Optically stimulated luminescence (OSL) showed that quartz had an unstable weak signal, and standard single aliquot regeneration (SAR) dose estimates were unreliable, as were doses from pulsed OSL and differential OSL. Infrared (IR<sub>50</sub>) and post-IR IR<sub>225</sub> stimulation (pIRIR<sub>225</sub>) signals from K-feldspar grains, on the other hand, gave stronger signals but were, to various extents, influenced by incomplete bleaching, fading and uncertainty due to high (&gt;2D<sub>0</sub>) doses. We find the uncorrected pIRIR<sub>225</sub> ages most reliable, though modern analogues indicate that there may be significant residual from incomplete bleaching for some of the samples. The results of the luminescence analyses, ages and sedimentology are put in the context of landscape dynamics and compared to the known glacial history of the Tatra Mountains.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00022023-11-22T00:00:00.000+00:00Complex Dose Rate Calculations in Luminescence Dating of Lacustrine and Palustrine Sediments from Niederweningen, Northern Switzerlandhttps://sciendo.com/article/10.2478/geochr-2023-0003<abstract> <title style='display:none'>Abstract</title> <p>This study focusses on dose rate determination in complex settings in two drill cores from the site of Niederweningen, northern Switzerland. A crosscheck with a certified standard material and neutron activation analyses (NAA) reveals an overall good performance of high-resolution gamma spectrometry (HR-GS) when determining dose rate-relevant elements. A second focus is on average water content during burial, by comparing measured sediment moisture with water uptake capability. Furthermore, layer models are used to investigate the impact of inhomogeneous stratification on dose rate. Finally, different scenarios to correct for radioactive disequilibrium in the uranium decay chain are investigated. While most of the applied corrections appear to have only a minor to moderate effect on age calculation, the results for one core are contradictory. Possibly, some of the applied correction scenarios are not reflecting the complex natural setting sufficiently, in particular average sediment moisture during burial and the timing of radioactive disequilibrium might be incorrectly estimated. While deposition in one core can be quite securely attributed to the period 100–70 ka, assigning the sediment sequence in the other core to the time between ca. 130 ka and 90 ka remains to some extent insecure.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00032023-11-16T00:00:00.000+00:00Determination of Radiocarbon Content in Bio-Oil Samples by Mini Carbon Dating System in the Gliwice Radiocarbon and Mass Spectrometry Laboratoryhttps://sciendo.com/article/10.2478/geochr-2023-0005<abstract> <title style='display:none'>Abstract</title> <p>The applications of isotopes are used by many European countries to investigate environmental changes. A compact modern accelerator mass spectrometry (AMS) system known as Mini Carbon Dating System (MICADAS) is used in Gliwice Radiocarbon and Mass Spectrometry Laboratory for determining the <sup>14</sup>C content in different environmental samples including liquid fuels. For radiocarbon measurement using MICADAS, the liquid samples are accurately prepared using the tin capsules for liquids for combustion in elemental analyser (EA) and graphitisation in the AGE system. In this study, the determination of <sup>14</sup>C content in three different bio-oil samples and one reference sample of 100% biomass was conducted. Bio-oil samples were prepared using tin capsules for liquids sealed in the second capsules for solids to avoid sample evaporation while the reference sample was prepared using the tin capsule for solids for combustion in EA and graphitisation in the AGE system. Based on the <sup>14</sup>C measurement results, one of the bio-oils was not produced from the analysed reference biomass. Two others were determined as a mixture of bio- and fossil components, and based on <sup>14</sup>C the bio-carbon content was calculated. For all samples, the <sup>14</sup>C measurement showed reproducible and reliable results.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00052023-11-16T00:00:00.000+00:00Radiocarbon Dated Pulse and Cereal Crops Indicate Diachronic Use of Iron Age Extreme Upland Sites in the Western Carpathians, Slovakiahttps://sciendo.com/article/10.2478/geochr-2023-0001<abstract> <title style='display:none'>Abstract</title> <p>Mountain summits in the Slovak part of the Western Carpathians bear evidence of human presence from the Late Bronze to the Late Iron Age. According to fire-induced changes in archaeological record and finds of weaponry, some of the extreme upland sites (EUS) were viewed as places of safety or <italic>refugia</italic> violently destroyed within a short period. We have focussed on three sites with summits at 1300–1550 m a. s. l. and found out that two of them were used in 650–400 calBC and 390–150 calBC, respectively. By the first systematic use of <sup>14</sup>C dating and targeted <sup>14</sup>C sampling, we have overcome the inherent chronological imprecision of their artefactual record and opened new vistas for interpretation of this type of sites.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00012023-06-23T00:00:00.000+00:00The Internal Dose Rate in Quartz Grains: Experimental Data and Consequences for Luminescence Datinghttps://sciendo.com/article/10.2478/geochr-2022-0002<abstract> <title style='display:none'>Abstract</title> <p>This work considers the impact of the internal alpha and beta dose rates in quartz grains obtained from sandy sediments on the results of luminescence dating. The internal dose rates reported here (ca. 0.01–0.21 Gy · ka<sup>−1</sup>) play a particularly important role, because of low (ca. 0.8–0.9 Gy · ka<sup>−1</sup>) or very low (ca. 0.4–0.6 Gy · ka<sup>−1</sup>) external dose rates. In these cases, the internal dose rates form a significant fraction of the total dose rates, often exceeding 10%. Ignoring this contribution would have made the considered luminescence ages artificially older. In our study, we measure both the internal alpha and beta contributions as the latter is usually neglected in the case of quartz. The dose rate measurements were performed using the innovative μDose system.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2022-00022022-12-10T00:00:00.000+00:00Evaluating the Effect of Hydrofluoric Acid Etching on Quartz Grains using Microscope Image Analysis, Laser Diffraction and Weight Loss Particle Size Estimatehttps://sciendo.com/article/10.2478/geochr-2022-0001<abstract> <title style='display:none'>Abstract</title> <p>In this work we investigate the quartz etching process using hydrofluoric acid for trapped charge dating (TCD) applications. It is done using material collected from an active sand mine in Bełchatów Nowy Świat, central Poland. Approximately 20 kg of material was collected and prepared using routine procedures that are applied in TCD laboratories. The material was sieved using 180–200 μm meshes, and the selected fraction was etched for various time intervals. Sieved samples were etched for durations from 0 min up to 180 min and measured with microscope image analysis (IA), laser diffraction (LD), and mass loss which were used to estimate the depths of etching. Our results show statistical data on how non-uniform the etching process is. We estimate this as a function of etching time from IA, LD and mass loss. In our investigation, mass loss measurements with the assumption of spherical grains correspond to the decrease of radius of ca. 0.151 ± 0.003 μm · min<sup>−1</sup>. In case of LD, a rough etch depth estimation corresponds to a range 0.06–0.18 μm · min<sup>−1</sup> with median at 0.13 μm · min<sup>−1</sup>. Microscope IA gives a 0.03–0.09 μm · min<sup>−1</sup> with a median at 0.05 μm · min<sup>−1</sup>. Moreover, quartz grains are fractured into smaller pieces while etching. It means that assumptions that are used in etch depth estimation from mass loss are not correct. They incorrect not only because grains are not spheres but also because the number of grains is not constant. Therefore, the etch depth estimated from mass loss might be overestimated. Using microscope IA we report etch depth ranges that might be used to roughly estimate the etch depth uncertainty.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2022-00012022-05-10T00:00:00.000+00:00Variations of Thermally and Optically Stimulated Luminescence Sensitivity of Loess and Pedocomplex Samples from Southern Tajikistan, Central Asiahttps://sciendo.com/article/10.1515/geochr-2015-0118<abstract> <title style='display:none'>Abstract</title> <p>To better understand the factors controlling the quartz luminescence sensitivity in loess deposits, samples from two loess sections in southern Tajikistan are investigated. Both pattern and amplitude in the variations of quartz luminescence sensitivity of these two sections are similar, showing higher values in pedocomplex units and lower values in the loess units. Similar trends of variation are found between the quartz luminescence sensitivity and climate proxies, including frequency-dependent magnetic susceptibility, median grain size and IRSL/[post-IR] OSL ratio. Laboratory experiments involving thermal activation and repeated bleaching/irradiation cycles reveal much larger sensitivity enhancement for samples with initial lower sensitivity from loess units than those from pedocomplex units with higher sensitivity. The observed systematic contrast in quartz luminescence sensitivity between the loess and pedocomplex units are interpreted as resulting from the differentiation of the weathering products from the source area and subsequent sensitization during the sedimentary transfer prior to deposition.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.1515/geochr-2015-01182021-12-31T00:00:00.000+00:00Applicability of OSL Dating to Fine-Grained Fluvial Deposits in the Mekong River Floodplain, Cambodiahttps://sciendo.com/article/10.2478/geochr-2020-0006<abstract> <title style='display:none'>Abstract</title> <p>Optically stimulated luminescence (OSL) dating of fine-grained (4–11 μm) fluvial sediments is rarely attempted but is crucial for constraining the evolution of mud-dominated floodplains. This study investigated the applicability of OSL dating to fine-grained deposits in the Mekong River, Cambodia based on a very young (&lt;600 yr) point-bar to riverbank succession and modern flood deposits. In succession, fine-grained quartz OSL provided the youngest ages, whereas age estimates by multi-grain sand-sized quartz OSL, and feldspar and polymineral infrared-stimulated luminescence are &gt;200 years older than the fine-grained quartz OSL age estimates. Ages of fine-grained quartz OSL are concordant with the minimum ages obtained from the single-grain quartz OSL. These results are supported by the generally small residual doses (&lt;0.1 Gy) measured in modern fine-grained flood-plain deposits. This indicates that fine-grained sediments in the Mekong River (Cambodia) are sufficiently bleached at deposition and can yield reliable quartz OSL ages for establishing the chronology of the floodplain. The sufficient bleaching of fine-grained quartz partly results from the long transport distance and may also occur in other large river systems.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2020-00062021-12-31T00:00:00.000+00:00ESR Chronology of Bedrock Fault Activity in Carbonate Area: Preliminary Results from the Study of the Lijiang-Xiaojinhe Fault, Southeastern Tibet, Chinahttps://sciendo.com/article/10.2478/geochr-2020-0033<abstract> <title style='display:none'>Abstract</title> <p>Carbonated rocks constitute one of the main lithologies of the southeastern Tibet area, China, a tectonically very active zone. However, due to the lack of suitable dating materials, it is difficult to carry out chronological studies of the local tectonic evolution in such carbonate areas. In the present study, electron spin resonance (ESR) method had been applied on the dating of carbonates heated during fault activity of the Lijiang-Xiaojinhe (LX) Fault, an important active fault located in the northwest of Yunnan Province. Clear displaced landforms show that the fault has undergone strong late-Quaternary activity. During the fault activity, the heat produced by friction lead to the melting of the frictional surface of the rocks, and the melting can attenuate or zero the ESR dating signal of carbonate. The aim of the present paper was to check the ability of carbonate use to chronologically identify fault activity using electron spin resonance (ESR) method. The results showed the last fault activity of the LX fault was dated by ESR about 2.0±0.2 ka ago, in agreement with historical and radiocarbon data. Hence ESR can be if necessary a practicable dating alternative method for the study of fault activity chronology in carbonate rock area.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2020-00332021-12-31T00:00:00.000+00:00The Application of Full Spectrum Analysis to NaI(Tl) Gamma Spectrometry for the Determination of Burial Dose Rateshttps://sciendo.com/article/10.2478/geochr-2020-0009<abstract> <title style='display:none'>Abstract</title> <p>In this study, we explored the potential of a NaI(Tl) scintillator-based gamma spectrometer for the accurate determination of burial dose rates in natural geological samples using a full spectrum analysis (FSA) approach. In this method, an iterative reweighted least-square regression is used to fit calibration standard spectra (<sup>40</sup>K, and <sup>238</sup>U and <sup>232</sup>Th series in equilibrium) to the sample spectrum, after subtraction of an appropriate background. The resulting minimum detection limits for <sup>40</sup>K, <sup>238</sup>U, and <sup>232</sup>Th are 4.8, 0.4 and 0.3 Bq·kg<sup>−1</sup>, respectively (for a 0.23 kg sample); this is one order of magnitude lower than those obtained with the three-window approach previously reported by us, and well below the concentrations found in most natural sediments. These improved values are also comparable to those from high-resolution HPGe gamma spectrometry. Almost all activity concentrations of <sup>40</sup>K, <sup>238</sup>U, and <sup>232</sup>Th from 20 measured natural samples differ by ≤5% from the high resolution spectrometry values; the average ratio of dose rates derived from our NaI(Tl) spectrometer to those from HPGe spectrometry is 0.993 ± 0.004 (n=20). We conclude that our scintillation spectrometry system employing FSA is a useful alternative laboratory method for accurate and precise determination of burial dose rates at a significantly lower cost than high resolution gamma spectrometry.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2020-00092021-12-31T00:00:00.000+00:00Cross-Calibration of an α-Source Used for Luminescence Dating by Applying Different Samples and Procedureshttps://sciendo.com/article/10.2478/geochr-2021-0003<abstract> <title style='display:none'>Abstract</title> <p>In terms of fine-grain luminescence dating applications, the efficiency of α-radiation in producing luminescence is an important issue when determining environmental dose rates. Efficiency is usually assessed by measuring the ratio of luminescence intensities induced by known α and β laboratory doses. Consequently, most thermoluminescence (TL)/optically stimulated luminescence (OSL) readers besides the standard <sup>90</sup>Sr/<sup>90</sup>Y β-source can also be equipped with a <sup>241</sup>Am α-source. A crucial point is, however, the calibration of these sources. The calibration of β-sources is routinely performed using standard quartz samples previously irradiated by a known γ-dose, though, in the case of α-sources, the procedure is less standardised, partly because there are no calibration materials with a known α-efficiency value.</p> <p>In this study, we aimed to cross-calibrate the built-in α-source of a RISØ TL/OSL DA-20 luminescence reader by testing and comparing five procedures, applying different samples (quartz and polymineral), different protocols multiple aliquot regeneration (MAR) and single aliquot regeneration (SAR) and different calibration sources. Throughout the tests, the performance of the fine-grain RISØ calibration quartz was also assessed.</p> <p>Regardless of the applied procedure, the calculated α-dose rates with one exception gave similar results. On the one hand, the applied polymineral sample due to potential fading, fairly high residuals after bleaching and relatively low infrared stimulated luminescence (IRSL) sensitivity proved to be the least optimal choice for cross-calibration. On the other hand, the tested natural fine grain quartz gave almost identical results when using different types of bleaching and different calibration α-sources. The mean dose rate determined for the source was 0.080 ± 0.004 Gy/s.</p> <p>The cross-calibration by using the RISØ fine grain quartz yielded somewhat higher but at the apparent uncertainty of luminescence dating still not significantly different dose rate for the source under calibration. Tests showed that the calibration quartz saturates at a relatively low α-dose, and the shape of α- and β-dose-response curves also depart from each other quite early, suggesting that cross-calibration with this material seems to be reliable only at low doses. For the first time, the <italic>a</italic>-value of the fine-grain calibration quartz was also determined using the freshly calibrated α-source, and the measurement yielded a 0.054 ± 0.003 value. We propose that after further validation of this result, the RISØ calibration quartz can ease the dose rate assessment of uncalibrated α-sources in the future.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2021-00032021-06-29T00:00:00.000+00:00Chronology of the Huxushan Paleolithic Site in South China: Inferred from Multiple Luminescence Dating Techniqueshttps://sciendo.com/article/10.2478/geochr-2020-0039<abstract> <title style='display:none'>Abstract</title> <p>The Huxushan archaeological site in northern Hunan Province, China, was recently excavated, from which stone tools including handaxes were unearthed. The deposits of the site are chemically weathered, which makes it difficult to date the site using numerical dating techniques except for optically stimulated luminescence (OSL) method. Here, we used various luminescence procedures including single-aliquot regenerative-dose (SAR), sensitivity-corrected multiple-aliquot regenerative-dose (SMAR) and thermally transferred optically stimulated luminescence (TT-OSL) SAR procedures on fine-grained quartz, and two-step post-infrared infrared stimulated luminescence (pIRIR) and multi-elevated-temperature pIRIR (MET-pIRIR) procedures on fine polymineral fractions. The results show that the fine quartz grains have excellent luminescence properties and the quartz SAR-, SMAR- and TT-OSL ages for the samples agree with each other and in stratigraphical order except for one sample. The fine polymineral fractions exhibited relatively weak pIRIR and MET-pIRIR signals, resulting in difficulty in constructing the dose-response curve for MET-pIRIR signals and the stratigraphically inconsistent pIRIR<sub>(100, 275)</sub> ages. The seven samples yielded their quartz OSL ages ranging from about 62 ka to 133 ka. The two samples from the cultural layer was dated to 78 to 92 ka using different procedures on fine quartz. However, given the systematically older pIRIR ages obtained with the fine polymineral grains for the two samples, their quartz OSL ages are considered to represent the minimal ages of this layer, and their pIRIR<sub>(100, 275)</sub> ages of 118 and 110 ka represent the upper age limit, indicating that the site was occupied by hominins during Marine Isotope Stage 5.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2020-00392021-12-31T00:00:00.000+00:00en-us-1