Pub Date : 2020-07-22DOI: 10.2478/geochr-2020-0002
Yandong Hou, H. Long, Lei Gao, Ji Shen
Abstract Luminescence dating technology has been used for chronological constraints on lacustrine sediments due to the ubiquitous materials (e.g., quartz and feldspar) as dosimeters, and a relatively long dating range, compared with the commonly used radiocarbon dating method. However, quartz dating on the Tibetan Plateau may suffer from dim and unstable luminescence signals. In the current study, we investigate a lake-related outcrop from the shore of Cuoe Lake on the central Tibetan Plateau. Both coarse-grained quartz and K-feldspar fractions were extracted, and OSL and post-IR IRSL signals were measured from these fractions, respectively. Combining the stratigraphy analysis and dating results, this study shows that: (1) quartz appears to be unsuitable for dating because of very dim natural signals and even anomalous fading (average g-value: 4.30 ± 2.51 %/decade). The suitability of the applied pIRIR protocol measured at 150°C (pIRIR150) for K-feldspar samples was confirmed by a set of luminescence tests; (2) compared with the luminescence-based chronology, the 14C age of shells from the same sediment layer yielded older age by ∼7 ka, which is likely attributed to hard water reservoir effect in Cuoe Lake; (3) the lake level reached its peak and maintained high-stand during the early Holocene (∼9.4–7.1 ka). This study highlights the applicability of K-feldspar luminescence dating when the counterpart quartz OSL is insensitive and encounters anomalous fading.
{"title":"Luminescence Dating of Lacustrine Sediments from Cuoe Lake on the Central Tibetan Plateau","authors":"Yandong Hou, H. Long, Lei Gao, Ji Shen","doi":"10.2478/geochr-2020-0002","DOIUrl":"https://doi.org/10.2478/geochr-2020-0002","url":null,"abstract":"Abstract Luminescence dating technology has been used for chronological constraints on lacustrine sediments due to the ubiquitous materials (e.g., quartz and feldspar) as dosimeters, and a relatively long dating range, compared with the commonly used radiocarbon dating method. However, quartz dating on the Tibetan Plateau may suffer from dim and unstable luminescence signals. In the current study, we investigate a lake-related outcrop from the shore of Cuoe Lake on the central Tibetan Plateau. Both coarse-grained quartz and K-feldspar fractions were extracted, and OSL and post-IR IRSL signals were measured from these fractions, respectively. Combining the stratigraphy analysis and dating results, this study shows that: (1) quartz appears to be unsuitable for dating because of very dim natural signals and even anomalous fading (average g-value: 4.30 ± 2.51 %/decade). The suitability of the applied pIRIR protocol measured at 150°C (pIRIR150) for K-feldspar samples was confirmed by a set of luminescence tests; (2) compared with the luminescence-based chronology, the 14C age of shells from the same sediment layer yielded older age by ∼7 ka, which is likely attributed to hard water reservoir effect in Cuoe Lake; (3) the lake level reached its peak and maintained high-stand during the early Holocene (∼9.4–7.1 ka). This study highlights the applicability of K-feldspar luminescence dating when the counterpart quartz OSL is insensitive and encounters anomalous fading.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45447536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-22DOI: 10.2478/geochr-2020-0004
H. Long, Hongyi Cheng, Linhai Yang, Lei Gao, Qian Liu
Abstract Lake shoreline beach ridges and their sediments have often been investigated as paleoenvironmental indicators in arid northern China. Robust chronology is crucial to utilize this archive for paleoenvironmental reconstruction and interpretation. In this study, we reported a robust chronology for the highest wave-built beach ridge around Jinchang paleolake at the northeast (NE) margin of the Tibetan Plateau, using a combined quartz and K-feldspar luminescence dating technique, together with radiocarbon dating. The consistent quartz and K-feldspar ages suggested the sufficient reset of luminescence signals before deposition for the investigated sediments. Both kinds of luminescence ages were in agreement with three independent 14C ages, further corroborating the robustness of these obtained luminescence ages. Our results demonstrated that the investigated beach ridge was formed around 8.5–6.9 ka, suggesting a distinct period of lake highstand which has been identified in other lakes nearby. This highstand event may implicate an increased regional moisture condition, which is likely caused by the increased Asian summer monsoon precipitation.
{"title":"Timing of Holocene Lake Highstand in Jinchang Paleolake from the Northeast Tibetan Plateau Foreland","authors":"H. Long, Hongyi Cheng, Linhai Yang, Lei Gao, Qian Liu","doi":"10.2478/geochr-2020-0004","DOIUrl":"https://doi.org/10.2478/geochr-2020-0004","url":null,"abstract":"Abstract Lake shoreline beach ridges and their sediments have often been investigated as paleoenvironmental indicators in arid northern China. Robust chronology is crucial to utilize this archive for paleoenvironmental reconstruction and interpretation. In this study, we reported a robust chronology for the highest wave-built beach ridge around Jinchang paleolake at the northeast (NE) margin of the Tibetan Plateau, using a combined quartz and K-feldspar luminescence dating technique, together with radiocarbon dating. The consistent quartz and K-feldspar ages suggested the sufficient reset of luminescence signals before deposition for the investigated sediments. Both kinds of luminescence ages were in agreement with three independent 14C ages, further corroborating the robustness of these obtained luminescence ages. Our results demonstrated that the investigated beach ridge was formed around 8.5–6.9 ka, suggesting a distinct period of lake highstand which has been identified in other lakes nearby. This highstand event may implicate an increased regional moisture condition, which is likely caused by the increased Asian summer monsoon precipitation.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41640049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-22DOI: 10.2478/geochr-2020-0003
S. Solongo, S. Tengis, G. Wagner, Hans Hüttel
Abstract In this study, we present results of luminescence dating using CW-OSL, LM-OSL and TL on heated quartz from the archaeological and historical site in Karakorum – the ancient capital of Mongolia, to test their convergence with the age control in the form of the Karakorum inscription 1346. The TL spectra conducted on quartz from red and grey coloured bricks appeared to be characteristic of the technological origin. Quartz TL from red bricks showed a UV emission band at ∼360 nm and a strong fast OSL component dominated signal. In contrast, blue emission detected in the TL spectra of grey coloured bricks, resulting possibly in the medium component dominated OSL signal. Finally, OSL and TL results gave dates from 1180±70 AD to 1360±70 consistent with the expected ages.
{"title":"CW-OSL, LM-OSL and TL Dating of Bricks from Karakorum, Mongolia: Insights from TL Spectra","authors":"S. Solongo, S. Tengis, G. Wagner, Hans Hüttel","doi":"10.2478/geochr-2020-0003","DOIUrl":"https://doi.org/10.2478/geochr-2020-0003","url":null,"abstract":"Abstract In this study, we present results of luminescence dating using CW-OSL, LM-OSL and TL on heated quartz from the archaeological and historical site in Karakorum – the ancient capital of Mongolia, to test their convergence with the age control in the form of the Karakorum inscription 1346. The TL spectra conducted on quartz from red and grey coloured bricks appeared to be characteristic of the technological origin. Quartz TL from red bricks showed a UV emission band at ∼360 nm and a strong fast OSL component dominated signal. In contrast, blue emission detected in the TL spectra of grey coloured bricks, resulting possibly in the medium component dominated OSL signal. Finally, OSL and TL results gave dates from 1180±70 AD to 1360±70 consistent with the expected ages.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49130183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-18DOI: 10.2478/geochr-2020-0005
V. Guilarte, M. Duval
Abstract In recent years, our investigation has been centred on improving the reliability and accuracy of the ESR method applied to quartz grains. As part of this ongoing investigation, we present an intra-laboratory study to evaluate the impact of different experimental setups on the ESR measurement precision and dose evaluation for ESR dating of optically bleached quartz grains. Repeated measurements of quartz samples have been performed at CENIEH, Spain, using two different Bruker spectrometers (EMXmicro and Elexsys E500) and resonators (standard rectangular ER4102ST and cylindrical Super High QE cavities). Their performance in terms of sensitivity, measurement repeatability and dose determination are presented in this study. This intra-laboratory work has allowed to evaluate the robustness of our protocol for ESR dating of quartz grains and to study the potential impact of different experimental setups on dose evaluation, which is essential for future standardization of the ESR dating method. Our results indicate that all the different experimental setups provide comparable precision of the ESR intensity measurements. Moreover, all the ESR dose estimates are within 1-sigma error, suggesting that it is possible to compare results obtained by different laboratories when similar analytical procedures are followed. Finally, the higher sensitivity achieved by the SHQE resonator appears to be of particular interest when dealing with samples showing low ESR signal intensities.
{"title":"ESR Dating of Optically Bleached Quartz Grains: Assessing the Impact of Different Experimental Setups on Dose Evaluations","authors":"V. Guilarte, M. Duval","doi":"10.2478/geochr-2020-0005","DOIUrl":"https://doi.org/10.2478/geochr-2020-0005","url":null,"abstract":"Abstract In recent years, our investigation has been centred on improving the reliability and accuracy of the ESR method applied to quartz grains. As part of this ongoing investigation, we present an intra-laboratory study to evaluate the impact of different experimental setups on the ESR measurement precision and dose evaluation for ESR dating of optically bleached quartz grains. Repeated measurements of quartz samples have been performed at CENIEH, Spain, using two different Bruker spectrometers (EMXmicro and Elexsys E500) and resonators (standard rectangular ER4102ST and cylindrical Super High QE cavities). Their performance in terms of sensitivity, measurement repeatability and dose determination are presented in this study. This intra-laboratory work has allowed to evaluate the robustness of our protocol for ESR dating of quartz grains and to study the potential impact of different experimental setups on dose evaluation, which is essential for future standardization of the ESR dating method. Our results indicate that all the different experimental setups provide comparable precision of the ESR intensity measurements. Moreover, all the ESR dose estimates are within 1-sigma error, suggesting that it is possible to compare results obtained by different laboratories when similar analytical procedures are followed. Finally, the higher sensitivity achieved by the SHQE resonator appears to be of particular interest when dealing with samples showing low ESR signal intensities.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44950165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-03DOI: 10.2478/geochr-2020-0006
Y. Ishii, T. Tamura, D. Collins, Bunnarin Ben
Abstract 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 (<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 >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 (<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.
{"title":"Applicability of OSL Dating to Fine-Grained Fluvial Deposits in the Mekong River Floodplain, Cambodia","authors":"Y. Ishii, T. Tamura, D. Collins, Bunnarin Ben","doi":"10.2478/geochr-2020-0006","DOIUrl":"https://doi.org/10.2478/geochr-2020-0006","url":null,"abstract":"Abstract 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 (<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 >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 (<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.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41405151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-30DOI: 10.1515/geochr-2015-0113
Qiuyue Zhao, M. Ding, Shuzhen Peng, Luo Wang, Wei Zhang, Bo Song, Rui Zhou, Jun-sheng Yue, Dongdong Zheng
Abstract The loess sediments widely distributed in the Central Shandong Mountains are sensitive records of East Asian monsoon changes for situating in a key region connected to the Eurasian Plate and the Pacific Ocean. However, the detailed processes of palaeoclimatic changes are poorly understood for the lack of high-resolution chronology. In this study, the chronology of Heishan loess palaeosol sequence in the Central Shandong Mountains is investigated using quartz SAR OSL and K-feldspar post-IR infrared (IR) stimulated luminescence (post-IR IRSL) dating method. The quartz is sensitive, fast component dominated and saturate at ∼150 Gy (∼50 ka). The measured K-feldspar pIRIR290 De showed no dependency on the first IR stimulation temperature between 50°C and 260°C. The K-feldspar pIRIR290 ages are consistent with the stratigraphy up to ∼75 ka. In establishing the chronological sequence for the study section, quartz OSL ages <50 ka and the K-feldspar pIRIR290 ages >50 ka were selected. Derived sedimentation rates show two relatively rapid stages of ∼32.0 ± 5.5 cm/ka for the palaeosol (∼11–8 ka) and ∼54.8 ± 1.1 cm/ka for the loess (∼34–30 ka). An erosional hiatus of loess between ∼30 ka and ∼17 ka is identified. We conclude that the pIRIR290 of loess sediments is applicable for samples during ∼8–75 ka.
{"title":"High Resolution Quartz OSL and K-feldspar post-IR IRSL Dating of Loess in the Central Shandong Mountains (Eastern China)","authors":"Qiuyue Zhao, M. Ding, Shuzhen Peng, Luo Wang, Wei Zhang, Bo Song, Rui Zhou, Jun-sheng Yue, Dongdong Zheng","doi":"10.1515/geochr-2015-0113","DOIUrl":"https://doi.org/10.1515/geochr-2015-0113","url":null,"abstract":"Abstract The loess sediments widely distributed in the Central Shandong Mountains are sensitive records of East Asian monsoon changes for situating in a key region connected to the Eurasian Plate and the Pacific Ocean. However, the detailed processes of palaeoclimatic changes are poorly understood for the lack of high-resolution chronology. In this study, the chronology of Heishan loess palaeosol sequence in the Central Shandong Mountains is investigated using quartz SAR OSL and K-feldspar post-IR infrared (IR) stimulated luminescence (post-IR IRSL) dating method. The quartz is sensitive, fast component dominated and saturate at ∼150 Gy (∼50 ka). The measured K-feldspar pIRIR290 De showed no dependency on the first IR stimulation temperature between 50°C and 260°C. The K-feldspar pIRIR290 ages are consistent with the stratigraphy up to ∼75 ka. In establishing the chronological sequence for the study section, quartz OSL ages <50 ka and the K-feldspar pIRIR290 ages >50 ka were selected. Derived sedimentation rates show two relatively rapid stages of ∼32.0 ± 5.5 cm/ka for the palaeosol (∼11–8 ka) and ∼54.8 ± 1.1 cm/ka for the loess (∼34–30 ka). An erosional hiatus of loess between ∼30 ka and ∼17 ka is identified. We conclude that the pIRIR290 of loess sediments is applicable for samples during ∼8–75 ka.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44465590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-26DOI: 10.1515/geochr-2015-0115
Mariana Sontag-González, M. Frouin, Bo Li, J. Schwenninger
Abstract Violet stimulation is a new development in optical dating which has been suggested to extend the upper age limit of optically simulated luminescence (OSL) dating of quartz. Despite the reported advantage, few validation tests and applications have been published so far. The present study investigated the violet stimulated luminescence (VSL) using a single aliquot regenerative dose (SAR) protocol and a multiple aliquot additive dose (MAAD) protocol. Sedimentary quartz samples from four archaeological sites in Europe with independent age controls spanning 40–900 ka were used, including Grotte Mandrin (France), Brooksby Quarry (UK), Cueva Negra del Estrecho del Río Quípar (Spain) and Sima de las Palomas del Cabezo Gordo (Spain). The equivalent dose of a relatively young sample (∼40 ka) was successfully determined. However, significant underestimations were observed for older samples with higher doses. These findings indicate the need for further development of the measurement protocol to date high-dose natural samples.
摘要紫激发是光学测年的一个新进展，它被认为可以延长石英光学模拟发光测年的年龄上限。尽管报道了这种优势，但到目前为止，很少有验证测试和应用发表。本研究使用单等分再生剂量（SAR）方案和多等分添加剂量（MAAD）方案研究了紫激发光（VSL）。使用了来自欧洲四个考古遗址的沉积石英样品，这些遗址的独立年龄控制范围为40-900 ka，包括Grotte Mandrin（法国）、Brooksby Quarry（英国）、Cueva Negra del Estreco del Río Quípar（西班牙）和Sima de las Palomas del Cabezo Gordo（西班牙）。成功测定了相对年轻的样品（～40ka）的等效剂量。然而，对于具有较高剂量的较老样本，观察到明显的低估。这些发现表明，有必要进一步开发迄今为止高剂量天然样品的测量方案。
{"title":"Assessing the Dating Potential of Violet Stimulated Luminescence Protocols","authors":"Mariana Sontag-González, M. Frouin, Bo Li, J. Schwenninger","doi":"10.1515/geochr-2015-0115","DOIUrl":"https://doi.org/10.1515/geochr-2015-0115","url":null,"abstract":"Abstract Violet stimulation is a new development in optical dating which has been suggested to extend the upper age limit of optically simulated luminescence (OSL) dating of quartz. Despite the reported advantage, few validation tests and applications have been published so far. The present study investigated the violet stimulated luminescence (VSL) using a single aliquot regenerative dose (SAR) protocol and a multiple aliquot additive dose (MAAD) protocol. Sedimentary quartz samples from four archaeological sites in Europe with independent age controls spanning 40–900 ka were used, including Grotte Mandrin (France), Brooksby Quarry (UK), Cueva Negra del Estrecho del Río Quípar (Spain) and Sima de las Palomas del Cabezo Gordo (Spain). The equivalent dose of a relatively young sample (∼40 ka) was successfully determined. However, significant underestimations were observed for older samples with higher doses. These findings indicate the need for further development of the measurement protocol to date high-dose natural samples.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47975434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-02DOI: 10.1515/geochr-2015-0114
Jun Peng
Abstract In optically stimulated luminescence (OSL) dating, statistical age models for equivalent dose (De) distributions are routinely estimated using the maximum likelihood estimation (MLE) method. In this study, a Markov chain Monte Carlo (MCMC) method was used to analyze statistical age models, including the central age model (CAM), the minimum age model (MAM), the maximum age model (MXAM), etc. This method was first used to obtain sampling distributions on parameters of interest in an age model using De distributions from individual sedimentary samples and subsequently extended to simultaneously extract age estimates from multiple samples with stratigraphic constraints. The MCMC method allows for the use of Bayesian inference to refine chronological sequences from multiple samples, including both fully and partially bleached OSL dates. This study designed easily implemented open-source numeric programs to perform MCMC sampling. Measured and simulated De distributions are used to validate the reliability of dose (age) estimates obtained by this method. Findings from this study demonstrate that estimates obtained by the MCMC method can be used to informatively compare results obtained by the MLE method. The application of statistical age models to multiple OSL dates with stratigraphic orders using the MCMC method may significantly improve both the precision and accuracy of burial ages.
{"title":"Analyzing Statistical Age Models to Determine the Equivalent Dose and Burial Age Using a Markov Chain Monte Carlo Method","authors":"Jun Peng","doi":"10.1515/geochr-2015-0114","DOIUrl":"https://doi.org/10.1515/geochr-2015-0114","url":null,"abstract":"Abstract In optically stimulated luminescence (OSL) dating, statistical age models for equivalent dose (De) distributions are routinely estimated using the maximum likelihood estimation (MLE) method. In this study, a Markov chain Monte Carlo (MCMC) method was used to analyze statistical age models, including the central age model (CAM), the minimum age model (MAM), the maximum age model (MXAM), etc. This method was first used to obtain sampling distributions on parameters of interest in an age model using De distributions from individual sedimentary samples and subsequently extended to simultaneously extract age estimates from multiple samples with stratigraphic constraints. The MCMC method allows for the use of Bayesian inference to refine chronological sequences from multiple samples, including both fully and partially bleached OSL dates. This study designed easily implemented open-source numeric programs to perform MCMC sampling. Measured and simulated De distributions are used to validate the reliability of dose (age) estimates obtained by this method. Findings from this study demonstrate that estimates obtained by the MCMC method can be used to informatively compare results obtained by the MLE method. The application of statistical age models to multiple OSL dates with stratigraphic orders using the MCMC method may significantly improve both the precision and accuracy of burial ages.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44197331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-29DOI: 10.1515/geochr-2015-0118
Yuetian Li, Liping Zhou
Abstract 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.
{"title":"Variations of Thermally and Optically Stimulated Luminescence Sensitivity of Loess and Pedocomplex Samples from Southern Tajikistan, Central Asia","authors":"Yuetian Li, Liping Zhou","doi":"10.1515/geochr-2015-0118","DOIUrl":"https://doi.org/10.1515/geochr-2015-0118","url":null,"abstract":"Abstract 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.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44420512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-04-29DOI: 10.1515/geochr-2015-0116
E. Şahiner, G. Polymeris, M. Öztürk, Y. Kadıoğlu, N. Meriç
Abstract This study provides methodological aspects on the equivalent dose estimation for travertine samples, namely heated calcium carbonate, using the TL multiple-aliquot additive-dose approach. Large equivalent doses (EDs), within the range 750–1300 Gy, were calculated using the plateau method based on the NTL glow curve. Moreover, a component resolved TL glow-peak analysis was carried out, using the integrated intensity of the NTL glow peaks for the ED estimation after deconvolution based on the OTOR model. Three different TL peaks were used, termed P4, P5 and P6. The integrated intensity of TL glow peak P4 resulted in age overestimation (15–26%), compared to the age provided using the plateau method. This overestimation could be attributed to the fact that the temperature range of P4 does not coincide with the plateau region of each sample. Milder overestimation (8–14%) was noticed using the integrated intensity of TL glow peak P6, mostly due to the poor deconvolution resolution. Only the integrated intensity of TL glow peak P5 after deconvolution provides ED values compatible with those yielded using the plateau method, with good accuracy. The present study suggests not using the TL intensity (neither in terms of integrated intensity nor of peak height intensity) for ED estimation; instead it is highly recommended to use either the plateau method, or alternatively integrated intensity of TL peak P5 after deconvolution. Unfortunately, using the peak height of TL P5 is not recommended, due to overlapping with P6.
{"title":"Component Resolved Equivalent Dose Estimation Using TL Glow Curves of Travertine Samples from Anatolia, Turkey","authors":"E. Şahiner, G. Polymeris, M. Öztürk, Y. Kadıoğlu, N. Meriç","doi":"10.1515/geochr-2015-0116","DOIUrl":"https://doi.org/10.1515/geochr-2015-0116","url":null,"abstract":"Abstract This study provides methodological aspects on the equivalent dose estimation for travertine samples, namely heated calcium carbonate, using the TL multiple-aliquot additive-dose approach. Large equivalent doses (EDs), within the range 750–1300 Gy, were calculated using the plateau method based on the NTL glow curve. Moreover, a component resolved TL glow-peak analysis was carried out, using the integrated intensity of the NTL glow peaks for the ED estimation after deconvolution based on the OTOR model. Three different TL peaks were used, termed P4, P5 and P6. The integrated intensity of TL glow peak P4 resulted in age overestimation (15–26%), compared to the age provided using the plateau method. This overestimation could be attributed to the fact that the temperature range of P4 does not coincide with the plateau region of each sample. Milder overestimation (8–14%) was noticed using the integrated intensity of TL glow peak P6, mostly due to the poor deconvolution resolution. Only the integrated intensity of TL glow peak P5 after deconvolution provides ED values compatible with those yielded using the plateau method, with good accuracy. The present study suggests not using the TL intensity (neither in terms of integrated intensity nor of peak height intensity) for ED estimation; instead it is highly recommended to use either the plateau method, or alternatively integrated intensity of TL peak P5 after deconvolution. Unfortunately, using the peak height of TL P5 is not recommended, due to overlapping with P6.","PeriodicalId":50421,"journal":{"name":"Geochronometria","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2020-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41763249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：