rss_2.0Geochronometria FeedSciendo RSS Feed for Geochronometriahttps://sciendo.com/journal/GEOCHRhttps://www.sciendo.comGeochronometria Feedhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/6471df00215d2f6c89db3b36/cover-image.jpghttps://sciendo.com/journal/GEOCHR140216Technical Carbon Black and Green Technologyhttps://sciendo.com/article/10.2478/geochr-2023-0016<abstract> <title style='display:none'>Abstract</title> <p>Carbon black (CB) is produced through the incomplete combustion of biomass or thermal decomposition in an oxygen-deprived environment. Technical carbon black (TCB) primarily consists of elemental carbon and comes in various grades distinguished by surface area and nanostructure morphologies. However, TCB production raises sustainability concerns due to its reliance on non-renewable feedstock, significant CO<sub>2</sub> emissions and high energy consumption. TCBs find extensive use as reinforcing fillers in the tire and rubber industries. Recent studies underscore the importance of eco-friendly alternatives. This research was carried out to monitor the renewability of the TCB samples by determining the <sup>14</sup>C isotope concentration. Liquid scintillation counting (LSC) and accelerator mass spectrometry (AMS) radiocarbon techniques were employed for measuring the <sup>14</sup>C isotope concentration, while isotope ratio mass spectrometry (IRMS) corrected standardised isotope fractionation correction. The investigation revealed that the examined TCB samples contain extremely low <sup>14</sup>C concentrations, measuring &lt;1 per cent modern carbon (pMC). This finding raises concerns regarding potential environmental ramifications.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00162024-03-18T00:00:00.000+00:00Insights From the Last Year’s Atmospheric CO Measurements in the Urban Atmosphere and the Natural Ecosystem in Southern Polandhttps://sciendo.com/article/10.2478/geochr-2023-0008<abstract> <title style='display:none'>Abstract</title> <p>This article aims to compare the molar fraction of atmospheric CO<sub>2</sub> measured in southern Poland, specifically in Gliwice (an urban area), Kraków (an urban area), and Kasprowy Wierch (a mountain environment) from August 2022 to March 2023. The study examines diurnal, monthly and seasonal variations in the molar fraction of CO<sub>2</sub>. Monthly and diurnal average CO<sub>2</sub> air mole fraction data are reported for Gliwice, Kraków, and Kasprowy Wierch during the specified period. The results reveal greater fluctuations in CO<sub>2</sub> amplitude in urban areas compared to the mountain environment. Significant differences in diurnal, nocturnal, monthly and seasonal variabilities of atmospheric CO<sub>2</sub> are observed in the urban sites. The findings suggest that the biosphere may act as a dominant source of local CO<sub>2</sub> in summer and fall, while other local or regional anthropogenic sources could impact CO<sub>2</sub> levels during winter and early spring, prior to the vegetation period. Additionally, this paper discusses challenges encountered during the use of a low-cost system (CARBOCAP GMP-343) for measuring CO<sub>2</sub> levels in the urban area of Gliwice in 2022.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00082024-03-18T00:00:00.000+00:00Impacts of Large-Scale Climate Oscillations on Fluvial Sediments in Central Poland: Evidence from Geochronological Analysishttps://sciendo.com/article/10.2478/geochr-2023-0018<abstract> <title style='display:none'>Abstract</title> <p>The article presents the results of a collective analysis of 181 radiocarbon and 38 luminescence dating results from the time range 50–11.7 cal kBP for samples originating in fluvial sedimentary environment in Łódź region (central Poland), south of the last glacial maximum (LGM) line. Four sites were selected for a general of fluvial deposits and the obtained dating results Struga Żłobnicka, Parchliny, Warenka, and Swędów regions. Based on the summed probability density function (PDF) curves, the study demonstrates the response of the fluvial sedimentary environment to events of overregional scale. The collective analysis of the radiocarbon age determinations from the Łódź region allows for observing the correlation between local environmental changes and large-scale changes recorded in the NGRIP core. The warming periods Greenland interstadials (GI)-3, GI-4, and GI-5.1, the cooling event GI-1b within the warming GI-1, as well as the transition between GI-1a and Greenland stadials (GS)-1, were most prominently recorded in the PDF curves. The collective analysis of the luminescence age determinations reflects a change in the river valleys, expressed by a strong aggradation during the cold maximum of the studied period.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00182024-03-18T00:00:00.000+00:00Lithostratigraphy and Chronology of Vistulian Periglacial Deposits in Józefów (Central Poland) Based on Luminescence Datinghttps://sciendo.com/article/10.2478/geochr-2023-0015<abstract> <title style='display:none'>Abstract</title> <p>Sediments in Józefów were deposited in a small lake in the Eemian Interglacial and Early Vistulian (MIS 5). They were then covered by periglacial mineral sediments during the Upper Pleniglacial and the Late Vistulian (MIS 2). These sediments were deformed by gelifluction and thermokarst processes. There is no traces of deposition from MIS 4 and MIS 3. Optically stimulated luminescence (OSL) dating confirmed the age of the sediments and enabled the reconstruction of the deposition phases and deformation of the lake infilling.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00152024-03-14T00:00:00.000+00:00Responses to Climate Factors in the Radial Growth of Schrenk Spruce () in the Yili Region, Northwest Chinahttps://sciendo.com/article/10.2478/geochr-2023-0012<abstract> <title style='display:none'>Abstract</title> <p>To examine the associations existing between elevation and tree growth, tree-ring width chronologies of Schrenk spruce (<italic>Picea schrenkiana</italic>) were developed from sampling sites at different elevations in the Wusun Mountain, Yili region, Xinjiang, northwest China. The radial growth of high-elevation trees was observed to be primarily influenced by meteorological factors in the non-growth season of the previous year. The radial growth of mid-elevation trees was mainly affected by temperature. The radial growth of low-elevation trees was mainly affected by both temperature and relative humidity. About climate change, the radial growth of Schrenk spruce at different elevations showed a non-uniform response to climate variables. Under the condition of intensified drought stress in the future, the forest ecosystem is likely to be greatly affected, and the radial growth of Schrenk spruce at low elevations will be especially inhibited.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00122024-03-14T00:00:00.000+00:00Morphology, Sedimentology and OSL Chronology of the Lower Prosna River System Evolution – A Case Study in Rokutów, West-Central Polandhttps://sciendo.com/article/10.2478/geochr-2023-0017<abstract> <title style='display:none'>Abstract</title> <p>This paper presents comprehensive investigations of the morphological, sedimentological, and stratigraphic features in the lower Prosna River valley infill, situated in west-central Poland. At the Rokutów site, we identified two meander generations and an anastomosing system. Fluvial changes observed depict the response of the extraglacial river system to climate fluctuations post-last glaciation. Following valley aggradation, scouring erosion, reaching depths of 9–10 m, likely occurred during the Bølling Interstadial. ‘Great meanders’ emerged during the Allerød-Younger Dryas, persisting for around 1000 years, with an uncommon upstream rotation influenced by the sub-Quaternary surface slope. A lengthy stabilization phase, lasting 8000–10,000 years, characterized by an anastomosing system with gradual aggradation, followed the great meandering period. About 3600–3900 years ago, the valley shifted back to a fluvial system with small meanders, lasting 600–900 years. Subsequently, the River Prosna reverted to an anastomosing system, remaining so until the 19th–20th centuries when it transformed into a single-channel system through regulatory manipulation. Our research suggests that the evolution of the Prosna River differed from other rivers across Western and Central Europe, exhibiting a blend of anastomosing and meandering phases.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/geochr-2023-00172024-03-05T00:00:00.000+00:00Electron 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+00:00en-us-1