Pub Date : 2025-04-02DOI: 10.1016/j.quageo.2025.101668
Yao Gu , Huayu Lu , Hongyan Zhang , Pengyu Lin , Xiaoyi Dong , Yao Wang , Shuangwen Yi , Fuzhi Lu , Fan Yang
High-resolution maar lake records with robust age control provide an ideal foundation for investigating paleoclimate change. However, in tropical-subtropical South China, the carbon reservoir effect of lake sediments is poorly understood, resulting in a lack of high precision records, hindering the comprehensive understanding of regional climate change and its forcing mechanism. In this study, based on a newly drilled core from the Tianyang (TY) maar lake located in South China, we conducted detailed radiocarbon dating of various materials to assess the reservoir effect and establish a reliable high-resolution chronology of the maar lake. Comparing radiocarbon ages of different grainsize and different fractions, the ages of bulk samples were closest to those of plant remains or charcoals which we consider as the reliable dating materials. Pairs of bulk samples and plant remain or charcoal ages indicate a limited but variable reservoir effect in TY maar lake. The reservoir effect is negligible from the surface to 623 cm (0–30.95 ka) and then gradually increased from negligible to approximately 700 years between the depth of 623–747 cm (30.95–37.15 ka). We hypothesize that the reservoir effect in the deeper part of the lake results from a combination of longer mean residence time due to lower sedimentation rates and increased groundwater level, which is linked to higher sea levels during the marine isotope stage 3 (MIS3). After reservoir correction, Bayesian age-depth modelling was performed based on 53 reliable radiocarbon ages, achieving a high-resolution chronology of TY maar lake covering the past ∼37 ka period with a mean age model uncertainty of 357 years, providing a reliable dating framework for paleoclimate reconstruction.
{"title":"High-precision radiocarbon dating and carbon reservoir effect of a maar lake in South China","authors":"Yao Gu , Huayu Lu , Hongyan Zhang , Pengyu Lin , Xiaoyi Dong , Yao Wang , Shuangwen Yi , Fuzhi Lu , Fan Yang","doi":"10.1016/j.quageo.2025.101668","DOIUrl":"10.1016/j.quageo.2025.101668","url":null,"abstract":"<div><div>High-resolution maar lake records with robust age control provide an ideal foundation for investigating paleoclimate change. However, in tropical-subtropical South China, the carbon reservoir effect of lake sediments is poorly understood, resulting in a lack of high precision records, hindering the comprehensive understanding of regional climate change and its forcing mechanism. In this study, based on a newly drilled core from the Tianyang (TY) maar lake located in South China, we conducted detailed radiocarbon dating of various materials to assess the reservoir effect and establish a reliable high-resolution chronology of the maar lake. Comparing radiocarbon ages of different grainsize and different fractions, the ages of bulk samples were closest to those of plant remains or charcoals which we consider as the reliable dating materials. Pairs of bulk samples and plant remain or charcoal ages indicate a limited but variable reservoir effect in TY maar lake. The reservoir effect is negligible from the surface to 623 cm (0–30.95 ka) and then gradually increased from negligible to approximately 700 years between the depth of 623–747 cm (30.95–37.15 ka). We hypothesize that the reservoir effect in the deeper part of the lake results from a combination of longer mean residence time due to lower sedimentation rates and increased groundwater level, which is linked to higher sea levels during the marine isotope stage 3 (MIS3). After reservoir correction, Bayesian age-depth modelling was performed based on 53 reliable radiocarbon ages, achieving a high-resolution chronology of TY maar lake covering the past ∼37 ka period with a mean age model uncertainty of 357 years, providing a reliable dating framework for paleoclimate reconstruction.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"88 ","pages":"Article 101668"},"PeriodicalIF":1.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-02-28DOI: 10.1016/j.quageo.2025.101659
M.D. Bateman , E. Davies , D.J.A. Evans , D.H. Roberts , E.R. Connell , E.J. Rhodes
Whether glacial sediments were exposed to light (bleached) prior to burial is uncertain but critical for luminescence dating. In such contexts, quartz can have unstable and weak signals, feldspar have less bleachable and fading signals and both require statistical modelling to extract the true burial age data. This paper presents a new approach using feldspars measured at multiple elevated temperatures (MET) and screened to select grains with plateau equivalent dose values which should be the well-bleached and unfaded grains upon which to base a true burial age. The MET plateau approach was tested on an aeolian site in Canada and two former UK glacial sites. When applied to the Canadian aeolian samples, it showed that the method successfully accepted mostly well-bleached grains whilst excluding grains with fading or that had poor luminescence characteristics. When applied to a well dated glacial sequence it yielded ages in good agreement with existing independent chronologies. A previously undated glacial site yielded stratigraphically consistent ages but these are thought likely to be slight age over-estimates due to extremely limited bleaching at deposition. In summary, the MET plateau approach improved avoidance of partially bleached grains, avoided corrections for residuals and/or fading and reduced the need for statistical models to interpret equivalent dose distributions. However, some glacial sediments may have had so limited bleaching that these may still not be easy to luminescence date. The MET plateau approach if adopted could allow re-evaluation of existing glacial chronologies and extend luminescence dating to more glacial sediments.
{"title":"Developing a new approach to the luminescence dating of sediments from glacial contexts","authors":"M.D. Bateman , E. Davies , D.J.A. Evans , D.H. Roberts , E.R. Connell , E.J. Rhodes","doi":"10.1016/j.quageo.2025.101659","DOIUrl":"10.1016/j.quageo.2025.101659","url":null,"abstract":"<div><div>Whether glacial sediments were exposed to light (bleached) prior to burial is uncertain but critical for luminescence dating. In such contexts, quartz can have unstable and weak signals, feldspar have less bleachable and fading signals and both require statistical modelling to extract the true burial age data. This paper presents a new approach using feldspars measured at multiple elevated temperatures (MET) and screened to select grains with plateau equivalent dose values which should be the well-bleached and unfaded grains upon which to base a true burial age. The MET plateau approach was tested on an aeolian site in Canada and two former UK glacial sites. When applied to the Canadian aeolian samples, it showed that the method successfully accepted mostly well-bleached grains whilst excluding grains with fading or that had poor luminescence characteristics. When applied to a well dated glacial sequence it yielded ages in good agreement with existing independent chronologies. A previously undated glacial site yielded stratigraphically consistent ages but these are thought likely to be slight age over-estimates due to extremely limited bleaching at deposition. In summary, the MET plateau approach improved avoidance of partially bleached grains, avoided corrections for residuals and/or fading and reduced the need for statistical models to interpret equivalent dose distributions. However, some glacial sediments may have had so limited bleaching that these may still not be easy to luminescence date. The MET plateau approach if adopted could allow re-evaluation of existing glacial chronologies and extend luminescence dating to more glacial sediments.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"87 ","pages":"Article 101659"},"PeriodicalIF":1.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-02-01DOI: 10.1016/j.quageo.2024.101649
Jaesoo Lim , Sangheon Yi , Sujeong Park , Arum Jung , Youngeun Kim , Sung Won Kim
Impact craters caused by meteorite collisions are phenomena that dramatically alter the Earth's surface and disturb the natural carbon cycle in subsequent sedimentary environments. To determine the impact date and impact-driven old carbon effects on radiocarbon cycles recorded in post-impact lake sediments, we performed radiocarbon (14C) dating of various organic fractions (humic acids, humins, charcoal, and organic plant fragments of various sizes) in post-impact lake sediments of the Hapcheon impact crater, Korea. Charcoal and plant fragments larger than 500 μm in the post-impact lake sediments of core 20CR09 constituted the oldest fraction (>45,000 cal BP), indicating pre-impact ages. Compared to micro-organic fragments (10–100 μm) consisting of terrestrial plant tissues, pollen, and limited freshwater algae with a narrow age range of 39,300–42,300 cal BP, the 100–500-μm plant fragments showed a slightly older age range of 41,670–43,910 cal BP throughout the 33-m-long lake sediment core. This suggests significant influence of well-mixed syn-impact organic fragments transported from slope deposits consisting of impact breccias and fallback deposits. Humin ages in the lake sediment of core 20CR05 were similar to those of the micro-plant fragments in core 20CR09, indicating that the humin fraction is mainly allochthonous. Humic acids at a depth of ca. 71 m, corresponding to the lowermost post-impact lake sediments (Stage 1), were dated to ∼21,000 cal BP, showing strong influence of post-impact humic acids ages. Whereas those from mid-depth lake sediments (Stage 2) were dated to 35,000–43,000 cal BP. This age reversal indicates increased input of syn-impact allochthonous humic acids, supported by positive correlation with terrestrial mineral input. This study demonstrated significant syn-impact radiocarbon effects and resultant age reversals in post-impact early lake sediments. The syn-impact age may be estimated by comparing ages of different-sized plant fragments (e.g., 10–100, 100–500, and >500 μm), humin, and humic acids. These findings suggest that climatic and environmental interpretations of these post-impact early lake sediments should be conducted only after testing various organic materials, if radiocarbon dating is applied. Lastly, compared to surrounding areas following natural climate changes, post-impact early lake environments in impact craters must be considered as anomalies with different ecosystems due to hydrothermal activity.
陨石碰撞造成的撞击坑是一种现象,它极大地改变了地球表面,扰乱了随后沉积环境中的自然碳循环。为了确定撞击日期和撞击驱动的旧碳对撞击后湖泊沉积物中放射性碳循环的影响,我们对韩国Hapcheon撞击坑撞击后湖泊沉积物中的各种有机组分(腐植酸、人类碱、木炭和不同大小的有机植物碎片)进行了放射性碳(14C)测年。20CR09岩心撞击后湖泊沉积物中粒径大于500 μm的木炭和植物碎片构成最古老的组分(> 45000 cal BP),反映了撞击前的年龄。与陆生植物组织、花粉和有限的淡水藻类组成的10 ~ 100 μm的微生物碎屑(年龄范围为39,300 ~ 42,300 cal BP)相比,100 ~ 500 μm的植物碎屑年龄范围略大,为41,670 ~ 43,910 cal BP。这表明,从由冲击角砾岩和回退沉积组成的斜坡沉积物中运移的混合良好的同冲有机碎屑具有重要影响。20CR05岩心湖底沉积物的人类年龄与20CR09岩心微植物碎屑的人类年龄相似,表明人类组分主要是异源的。约71 m深度的腐植酸,对应于撞击后最底部的湖泊沉积物(阶段1),其年代为~ 21,000 cal BP,显示出撞击后腐植酸年龄的强烈影响。而中深湖沉积物(阶段2)的年代为35000 ~ 43000 cal BP。这种年龄反转表明同冲异源腐殖酸输入增加,与陆源矿物输入正相关。该研究表明,在撞击后的早期湖泊沉积物中存在显著的同步撞击放射性碳效应和由此产生的年龄反转。可以通过比较不同大小的植物碎片(如10-100 μm、100-500 μm和>;500 μm)、腐植酸和腐植酸的年龄来估计同冲年龄。这些发现表明,如果采用放射性碳定年法,这些撞击后早期湖泊沉积物的气候和环境解释应该只有在测试了各种有机物质之后才能进行。最后,与自然气候变化后的周边地区相比,由于热液活动,撞击后的早期湖泊环境必须被视为不同生态系统的异常。
{"title":"Radiocarbon age anomalies in post-impact lake sediments of the Hapcheon impact crater, Korea and their implication for crater evolution","authors":"Jaesoo Lim , Sangheon Yi , Sujeong Park , Arum Jung , Youngeun Kim , Sung Won Kim","doi":"10.1016/j.quageo.2024.101649","DOIUrl":"10.1016/j.quageo.2024.101649","url":null,"abstract":"<div><div>Impact craters caused by meteorite collisions are phenomena that dramatically alter the Earth's surface and disturb the natural carbon cycle in subsequent sedimentary environments. To determine the impact date and impact-driven old carbon effects on radiocarbon cycles recorded in post-impact lake sediments, we performed radiocarbon (<sup>14</sup>C) dating of various organic fractions (humic acids, humins, charcoal, and organic plant fragments of various sizes) in post-impact lake sediments of the Hapcheon impact crater, Korea. Charcoal and plant fragments larger than 500 μm in the post-impact lake sediments of core 20CR09 constituted the oldest fraction (>45,000 cal BP), indicating pre-impact ages. Compared to micro-organic fragments (10–100 μm) consisting of terrestrial plant tissues, pollen, and limited freshwater algae with a narrow age range of 39,300–42,300 cal BP, the 100–500-μm plant fragments showed a slightly older age range of 41,670–43,910 cal BP throughout the 33-m-long lake sediment core. This suggests significant influence of well-mixed syn-impact organic fragments transported from slope deposits consisting of impact breccias and fallback deposits. Humin ages in the lake sediment of core 20CR05 were similar to those of the micro-plant fragments in core 20CR09, indicating that the humin fraction is mainly allochthonous. Humic acids at a depth of ca. 71 m, corresponding to the lowermost post-impact lake sediments (Stage 1), were dated to ∼21,000 cal BP, showing strong influence of post-impact humic acids ages. Whereas those from mid-depth lake sediments (Stage 2) were dated to 35,000–43,000 cal BP. This age reversal indicates increased input of syn-impact allochthonous humic acids, supported by positive correlation with terrestrial mineral input. This study demonstrated significant syn-impact radiocarbon effects and resultant age reversals in post-impact early lake sediments. The syn-impact age may be estimated by comparing ages of different-sized plant fragments (e.g., 10–100, 100–500, and >500 μm), humin, and humic acids. These findings suggest that climatic and environmental interpretations of these post-impact early lake sediments should be conducted only after testing various organic materials, if radiocarbon dating is applied. Lastly, compared to surrounding areas following natural climate changes, post-impact early lake environments in impact craters must be considered as anomalies with different ecosystems due to hydrothermal activity.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"86 ","pages":"Article 101649"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.quageo.2024.101648
Li Liu, Shengli Yang, Pushuang Li, Jingzhao Zhang, Rui Li, Dongxue Li, Xuechao Xu, Yuanlong Luo, Xiuyun Yang
The multi-aliquot regenerative dose (MAR) multi-elevated-temperature post-infrared infrared stimulated luminescence (MET-pIRIR) dating protocol exhibits great potential for extending the luminescence dating limit. However, further investigations are needed. Loess deposits on the Tibetan Plateau (TP) significantly differ from those on the Chinese Loess Plateau in terms of both formation age and dust source, making them ideal for studying the past climatic and environmental changes on the TP. However, detailed chronological studies are lacking. This study investigates the applicability of the MAR MET-pIRIR protocol to the Danba (DB) loess-paleosol sequence in the eastern TP, aiming to establish a chronological framework for this typical loess sequence. For TP loess samples with equivalent doses (De) below ∼950 Gy, multi-aliquot MET-pIRIR250 and single-aliquot pIR200IR290 dating methods yield consistent results. However, for samples with De exceeding ∼950 Gy, the SAR-pIR200IR290 method underestimates ages, while the MAR MET-pIRIR250 procedure remains reliable up to ∼1100 Gy. Using MAR MET-pIRIR protocol with the global standard growth curve method, we have established a new absolute chronological framework for the DB loess-paleosol sequence, indicating that loess deposition in the TP began at least ∼230 ka ago. The magnetic susceptibility records of this loess sequence reveal a pattern of alternating moist interglacial and dry glacial periods. During the last interglacial period, precipitation levels were significantly elevated and exhibited considerable variation in the eastern TP.
{"title":"First investigation of the luminescence dating of loess in the eastern Tibetan Plateau using K-feldspar MAR MET-pIRIR protocol","authors":"Li Liu, Shengli Yang, Pushuang Li, Jingzhao Zhang, Rui Li, Dongxue Li, Xuechao Xu, Yuanlong Luo, Xiuyun Yang","doi":"10.1016/j.quageo.2024.101648","DOIUrl":"10.1016/j.quageo.2024.101648","url":null,"abstract":"<div><div>The multi-aliquot regenerative dose (MAR) multi-elevated-temperature post-infrared infrared stimulated luminescence (MET-pIRIR) dating protocol exhibits great potential for extending the luminescence dating limit. However, further investigations are needed. Loess deposits on the Tibetan Plateau (TP) significantly differ from those on the Chinese Loess Plateau in terms of both formation age and dust source, making them ideal for studying the past climatic and environmental changes on the TP. However, detailed chronological studies are lacking. This study investigates the applicability of the MAR MET-pIRIR protocol to the Danba (DB) loess-paleosol sequence in the eastern TP, aiming to establish a chronological framework for this typical loess sequence. For TP loess samples with equivalent doses (D<sub>e</sub>) below ∼950 Gy, multi-aliquot MET-pIRIR<sub>250</sub> and single-aliquot pIR<sub>200</sub>IR<sub>290</sub> dating methods yield consistent results. However, for samples with D<sub>e</sub> exceeding ∼950 Gy, the SAR-pIR<sub>200</sub>IR<sub>290</sub> method underestimates ages, while the MAR MET-pIRIR<sub>250</sub> procedure remains reliable up to ∼1100 Gy. Using MAR MET-pIRIR protocol with the global standard growth curve method, we have established a new absolute chronological framework for the DB loess-paleosol sequence, indicating that loess deposition in the TP began at least ∼230 ka ago. The magnetic susceptibility records of this loess sequence reveal a pattern of alternating moist interglacial and dry glacial periods. During the last interglacial period, precipitation levels were significantly elevated and exhibited considerable variation in the eastern TP.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"86 ","pages":"Article 101648"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-02-01DOI: 10.1016/j.quageo.2024.101647
Li Wang , Katherine H. Roucoux , Althea L. Davies , Shuang Zhang , Chunqing Sun , Richard T. Streeter , William Hutchison , Ian T. Lawson
Cryptotephras have been widely used as a chronological tool for studying past environmental change, but many temporal and spatial gaps remain in our knowledge of the distribution of cryptotephra records. Here, last millennium cryptotephras were identified and analysed for the first time in eastern lowland Scotland. Six tephra layers were identified in six replicate short peat cores at Bankhead Moss, a raised bog in Fife, eastern lowland Scotland. Geochemical and stratigraphic correlations indicate that the tephras originate from Icelandic and Alaskan sources. We make firm correlations to Askja 1875 and WRAe, a broad correlation to Mount Churchill with the possibility of Lena tephra being inferred from its estimated timing, and uncertain correlations of three tephra layers of Icelandic origin, considering the mixed nature of these three tephra layers under the potential influence from post-depositional reworking and multiple volcanic sources, e.g. Hekla, Öræfajökull and Katla. This is the first secure record of the Askja 1875 tephra in the British Isles, which significantly extends its known spatial distribution and suggests a more complex dispersal pattern of this tephra than previously thought. Persistent presence of shards throughout parts of the peat sequences may reflect post-depositional movement of tephra shards within the peat, reworking from surrounding landscape, and/or sparse fallout from other eruptions. Our records indicate that any single peat core from this site gives a good approximation of the overall tephrostratigraphy, but there is considerable spatial variation in tephra concentrations between cores. Age-depth models for the six cores based on cryptotephras, spheroidal carbonaceous particle (SCP) counts, and radiocarbon dates likewise vary between cores, showing a pattern consistent with peat accumulation in a domed raised bog. These spatial differences in tephrostratigraphy highlight the value of a multiple-core approach in palaeoenvironmental peatland research.
{"title":"A new tephrochronological record of a raised bog in eastern lowland Scotland","authors":"Li Wang , Katherine H. Roucoux , Althea L. Davies , Shuang Zhang , Chunqing Sun , Richard T. Streeter , William Hutchison , Ian T. Lawson","doi":"10.1016/j.quageo.2024.101647","DOIUrl":"10.1016/j.quageo.2024.101647","url":null,"abstract":"<div><div>Cryptotephras have been widely used as a chronological tool for studying past environmental change, but many temporal and spatial gaps remain in our knowledge of the distribution of cryptotephra records. Here, last millennium cryptotephras were identified and analysed for the first time in eastern lowland Scotland. Six tephra layers were identified in six replicate short peat cores at Bankhead Moss, a raised bog in Fife, eastern lowland Scotland. Geochemical and stratigraphic correlations indicate that the tephras originate from Icelandic and Alaskan sources. We make firm correlations to Askja 1875 and WRAe, a broad correlation to Mount Churchill with the possibility of Lena tephra being inferred from its estimated timing, and uncertain correlations of three tephra layers of Icelandic origin, considering the mixed nature of these three tephra layers under the potential influence from post-depositional reworking and multiple volcanic sources, e.g. Hekla, Öræfajökull and Katla. This is the first secure record of the Askja 1875 tephra in the British Isles, which significantly extends its known spatial distribution and suggests a more complex dispersal pattern of this tephra than previously thought. Persistent presence of shards throughout parts of the peat sequences may reflect post-depositional movement of tephra shards within the peat, reworking from surrounding landscape, and/or sparse fallout from other eruptions. Our records indicate that any single peat core from this site gives a good approximation of the overall tephrostratigraphy, but there is considerable spatial variation in tephra concentrations between cores. Age-depth models for the six cores based on cryptotephras, spheroidal carbonaceous particle (SCP) counts, and radiocarbon dates likewise vary between cores, showing a pattern consistent with peat accumulation in a domed raised bog. These spatial differences in tephrostratigraphy highlight the value of a multiple-core approach in palaeoenvironmental peatland research.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"86 ","pages":"Article 101647"},"PeriodicalIF":1.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-01-09DOI: 10.1016/j.quageo.2025.101650
Elena Serra , Daniela Mueller , Lukas Gegg , Gustav Firla , Francesca Piccoli , Stefan Hergarten , Audrey Margirier , Frank Preusser
Constraining the age of glaciofluvial deposits is essential for reconstructing paleoglacial dynamics. While luminescence dating is among the most commonly used approaches, incomplete resetting of the signal before sediment deposition makes its application to such deposits challenging. Single grain (SG) and cobble luminescence dating have been used to account for heterogeneous bleaching with different success, and are tested here in combination on glaciofluvial deposits from one site in the northern Alpine foreland. Previous chronological investigations indicate that deposition of the proglacial outwash occurred ca. 29 ka ago. SG feldspar results on sand lens and gravel sandy matrix samples underestimate the previous age estimates due to the occurrence of grains with low equivalent dose (De) values. When low De values are discarded, the estimated ages are in agreement with the independent constraints. Luminescence-depth profiles obtained from four cobbles show (1) no or only shallow bleaching, and (2) high variability between cores and surfaces of the same clast. Both aspects highlight the necessity of measuring numerous clasts and several cores in order to detect well-bleached clasts and profiles. The limited signal resetting can be explained by the proximity of the deposit to the glacial front. The intra-cobble variability is instead potentially related to heterogeneity in the cobbles’ lithology, implying differences in dosimetry, signal stability and light attenuation within the clasts. Electron microprobe analyses of feldspar in the clasts and comparison with the independent age constraints suggest that (1) the luminescence signal of the rock slices derive from both Na- and K-rich feldspars and (2) an average internal potassium content may be a good first order estimate for dose rate calculations. Overall, the present study highlights both the challenges and the potential of applying SG and cobble luminescence dating to partially bleached glaciofluvial deposits.
{"title":"Combined single grain and cobble luminescence dating of poorly bleached glaciofluvial deposits from the Swiss Alpine foreland","authors":"Elena Serra , Daniela Mueller , Lukas Gegg , Gustav Firla , Francesca Piccoli , Stefan Hergarten , Audrey Margirier , Frank Preusser","doi":"10.1016/j.quageo.2025.101650","DOIUrl":"10.1016/j.quageo.2025.101650","url":null,"abstract":"<div><div>Constraining the age of glaciofluvial deposits is essential for reconstructing paleoglacial dynamics. While luminescence dating is among the most commonly used approaches, incomplete resetting of the signal before sediment deposition makes its application to such deposits challenging. Single grain (SG) and cobble luminescence dating have been used to account for heterogeneous bleaching with different success, and are tested here in combination on glaciofluvial deposits from one site in the northern Alpine foreland. Previous chronological investigations indicate that deposition of the proglacial outwash occurred ca. 29 ka ago. SG feldspar results on sand lens and gravel sandy matrix samples underestimate the previous age estimates due to the occurrence of grains with low equivalent dose (D<sub>e</sub>) values. When low D<sub>e</sub> values are discarded, the estimated ages are in agreement with the independent constraints. Luminescence-depth profiles obtained from four cobbles show (1) no or only shallow bleaching, and (2) high variability between cores and surfaces of the same clast. Both aspects highlight the necessity of measuring numerous clasts and several cores in order to detect well-bleached clasts and profiles. The limited signal resetting can be explained by the proximity of the deposit to the glacial front. The intra-cobble variability is instead potentially related to heterogeneity in the cobbles’ lithology, implying differences in dosimetry, signal stability and light attenuation within the clasts. Electron microprobe analyses of feldspar in the clasts and comparison with the independent age constraints suggest that (1) the luminescence signal of the rock slices derive from both Na- and K-rich feldspars and (2) an average internal potassium content may be a good first order estimate for dose rate calculations. Overall, the present study highlights both the challenges and the potential of applying SG and cobble luminescence dating to partially bleached glaciofluvial deposits.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"87 ","pages":"Article 101650"},"PeriodicalIF":1.7,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143141313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.quageo.2024.101638
Mariana Sontag-González , Bo Li , Kieran O'Gorman , Basran Burhan , Budianto Hakim , Adam Brumm , Richard G. Roberts
Volcanic sediments are challenging to date with luminescence-based methods. Both main minerals used for dating—quartz and K-rich feldspar—commonly have suboptimal luminescence properties when of volcanic origins, primarily a low signal intensity and, for K-rich feldspars, high rates of anomalous fading. The present work provides a case study of sediment samples from the Leang Bulu Bettue (LBB) archaeological site in Indonesia, a key site in our understanding of the early human occupation of the island of Sulawesi. We show that currently available state-of-the-art methods can provide robust optical ages for volcanic sediments. Through various reliability tests, we establish the suitability of a post-IR IR stimulated luminescence (pIRIR) standardised growth curve (SGC) procedure for De estimation of ‘micro-aliquots’ containing 5–10 grains of K-rich feldspar, and then combine this method with estimates of environmental dose rate to determine 10 new reliable and finite optical ages for the sedimentary deposits at LBB. Furthermore, by applying the LnTn method to circumvent truncation of the De distribution caused by the non-linearity of the dose response curve in the higher dose range, we could extend the site's luminescence-based chronology to span the interval ∼15–210 ka. The new chronology is in keeping with previous radiocarbon and U-series ages for the site's upper layers. We show that the low fading rate of micro-aliquots relative to using large aliquots composed of hundreds of grains lies in a brightness-based selection. By targeting bright grains with low fading rates, the need for fading corrections is greatly reduced and they can be made with a smaller uncertainty propagated through into the final age estimate, resulting in optical ages of improved accuracy and precision for volcanic sediments.
用基于发光的方法确定火山沉积物的年代具有挑战性。用于测定年代的两种主要矿物--石英和富钾长石--在火山成因中通常都具有次优的发光特性,主要是信号强度低,而对于富钾长石来说,异常衰减率高。本研究对印度尼西亚 Leang Bulu Bettue(LBB)考古遗址的沉积物样本进行了案例研究,该考古遗址是我们了解人类早期占领苏拉威西岛的关键地点。我们的研究表明,目前最先进的方法可以为火山沉积物提供可靠的光学年龄。通过各种可靠性测试,我们确定了后红外红外激发发光(pIRIR)标准化生长曲线(SGC)程序是否适用于估算含有 5-10 粒富含钾长石的 "微小碱块 "的年龄,然后将该方法与环境剂量率估算相结合,为 LBB 沉积物确定了 10 个新的可靠和有限的光学年龄。此外,通过应用 LnTn 方法来规避高剂量范围内剂量响应曲线的非线性所造成的 De 分布截断,我们可以将该遗址基于发光的年代学扩展到 15-210 ka 之间。新的年代学与之前遗址上层的放射性碳和铀系列年龄相一致。我们的研究表明,相对于使用由数百个颗粒组成的大样本,微样本的低衰减率在于基于亮度的选择。通过选择衰减率低的明亮颗粒,大大减少了对衰减校正的需求,而且在进行衰减校正时,最终年龄估计的不确定性较小,从而提高了火山沉积物光学年龄的准确性和精确度。
{"title":"Survival of the brightest? pIRIR dating of volcanic sediments in Sulawesi, Indonesia, using micro-aliquots of K-rich feldspar","authors":"Mariana Sontag-González , Bo Li , Kieran O'Gorman , Basran Burhan , Budianto Hakim , Adam Brumm , Richard G. Roberts","doi":"10.1016/j.quageo.2024.101638","DOIUrl":"10.1016/j.quageo.2024.101638","url":null,"abstract":"<div><div>Volcanic sediments are challenging to date with luminescence-based methods. Both main minerals used for dating—quartz and K-rich feldspar—commonly have suboptimal luminescence properties when of volcanic origins, primarily a low signal intensity and, for K-rich feldspars, high rates of anomalous fading. The present work provides a case study of sediment samples from the Leang Bulu Bettue (LBB) archaeological site in Indonesia, a key site in our understanding of the early human occupation of the island of Sulawesi. We show that currently available state-of-the-art methods can provide robust optical ages for volcanic sediments. Through various reliability tests, we establish the suitability of a post-IR IR stimulated luminescence (pIRIR) standardised growth curve (SGC) procedure for D<sub>e</sub> estimation of ‘micro-aliquots’ containing 5–10 grains of K-rich feldspar, and then combine this method with estimates of environmental dose rate to determine 10 new reliable and finite optical ages for the sedimentary deposits at LBB. Furthermore, by applying the L<sub>n</sub>T<sub>n</sub> method to circumvent truncation of the D<sub>e</sub> distribution caused by the non-linearity of the dose response curve in the higher dose range, we could extend the site's luminescence-based chronology to span the interval ∼15–210 ka. The new chronology is in keeping with previous radiocarbon and U-series ages for the site's upper layers. We show that the low fading rate of micro-aliquots relative to using large aliquots composed of hundreds of grains lies in a brightness-based selection. By targeting bright grains with low fading rates, the need for fading corrections is greatly reduced and they can be made with a smaller uncertainty propagated through into the final age estimate, resulting in optical ages of improved accuracy and precision for volcanic sediments.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"85 ","pages":"Article 101638"},"PeriodicalIF":1.7,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-26DOI: 10.1016/j.quageo.2024.101636
Su-Chin Chang , Mei-Fei Chu , Wen-Shan Chen , Stephen E. Cox , Sidney R. Hemming
Determining the exact age of volcanic activity in the Northern Taiwan Volcanic Zone (NTVZ) is essential for comprehending Taiwan's tectonic evolution. The timing and duration of the volcanic processes that formed the NTVZ remain uncertain despite the availability of geochronological, geochemical, and geophysical data. While extensive efforts have been directed towards investigating the age of the Tatun Volcanic Group, the primary feature of the NTVZ, many other aspects require further examination. This study concentrates on two offshore islets in the northern region of the NTVZ. We present new 40Ar/39Ar ages of 0.252 ± 0.018 Ma for a lava flow, representing an early stage of volcanic activity, and 0.118 ± 0.012 Ma for a dike, representing the latest stage of volcanic activity around Pengjia Islet. A sample collected from Mianhua Islet did not yield a reasonable age due to high uncertainty, likely attributable to young and low radiogenic argon. Field observations support the interpretation that volcanic activity on both islets is considerably younger than previously estimated. This study corroborates the hypothesis from geophysical studies that submarine NTVZ features to record a potentially active magmatic reservoir offshore of northern Taiwan. By refining our understanding of spatio-temporal patterns in volcanic activity, this study contributes to volcanic hazard assessment in Taiwan and surrounding areas.
{"title":"Novel age constraints on offshore islets around Taiwan with implications for the northern Taiwan volcanic zone","authors":"Su-Chin Chang , Mei-Fei Chu , Wen-Shan Chen , Stephen E. Cox , Sidney R. Hemming","doi":"10.1016/j.quageo.2024.101636","DOIUrl":"10.1016/j.quageo.2024.101636","url":null,"abstract":"<div><div>Determining the exact age of volcanic activity in the Northern Taiwan Volcanic Zone (NTVZ) is essential for comprehending Taiwan's tectonic evolution. The timing and duration of the volcanic processes that formed the NTVZ remain uncertain despite the availability of geochronological, geochemical, and geophysical data. While extensive efforts have been directed towards investigating the age of the Tatun Volcanic Group, the primary feature of the NTVZ, many other aspects require further examination. This study concentrates on two offshore islets in the northern region of the NTVZ. We present new <sup>40</sup>Ar/<sup>39</sup>Ar ages of 0.252 ± 0.018 Ma for a lava flow, representing an early stage of volcanic activity, and 0.118 ± 0.012 Ma for a dike, representing the latest stage of volcanic activity around Pengjia Islet. A sample collected from Mianhua Islet did not yield a reasonable age due to high uncertainty, likely attributable to young and low radiogenic argon. Field observations support the interpretation that volcanic activity on both islets is considerably younger than previously estimated. This study corroborates the hypothesis from geophysical studies that submarine NTVZ features to record a potentially active magmatic reservoir offshore of northern Taiwan. By refining our understanding of spatio-temporal patterns in volcanic activity, this study contributes to volcanic hazard assessment in Taiwan and surrounding areas.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"85 ","pages":"Article 101636"},"PeriodicalIF":1.7,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-24DOI: 10.1016/j.quageo.2024.101635
Xingshuo Xu , Chuanyi Wei , Gongming Yin , Hao Ji , Chunru Liu , Lin Zhao , Huili Yang , Guang Yang
The Ti–H center exhibits rapid and complete optical bleaching properties, meaning it has significant potential for dating applications. However, the equivalent dose of Ti–H centers is underestimated when total doses received by quartz during its geological history reaches a higher level, and there appears to be linked to saturation of the equivalent dose obtained from Ti–H centers. To investigate this phenomenon, a series of samples were analyzed from two sections at Ximachi in Heqing County, China, which have strong Ti–H signals. The sample ages were obtained using the electron spin resonance (ESR) multiple-centers approach, and the reliability of the ages was validated by comparison with optically simulated luminescence (OSL) ages and between different paramagnetic centers. The ESR data demonstrate that the Ti–H centers can provide accurate dose estimates up to 750–950 Gy, with varying degrees of underestimation at high doses. Combined with previously published Ti–H data, it is evident that the upper threshold of the accurate data obtained from Ti–H centers depends on the sample, and may be positively correlated with the Ti–H/(Ti–Li + Ti–H) ratio (option C/D). According to the provenance significance of the Ti–H/(Ti–Li + Ti–H) ratio, we propose that the Ximachi samples have high Ti–H/(Ti–Li + Ti–H) ratios and then equivalent dose saturation values of Ti–H centers, which may be related to the thermal history of the analyzed quartz grains.
{"title":"Application of multiple-centers ESR dating to middle Pleistocene fluviolacustrine sediments and insights into the dose underestimation from the Ti–H center at high equivalent doses","authors":"Xingshuo Xu , Chuanyi Wei , Gongming Yin , Hao Ji , Chunru Liu , Lin Zhao , Huili Yang , Guang Yang","doi":"10.1016/j.quageo.2024.101635","DOIUrl":"10.1016/j.quageo.2024.101635","url":null,"abstract":"<div><div>The Ti–H center exhibits rapid and complete optical bleaching properties, meaning it has significant potential for dating applications. However, the equivalent dose of Ti–H centers is underestimated when total doses received by quartz during its geological history reaches a higher level, and there appears to be linked to saturation of the equivalent dose obtained from Ti–H centers. To investigate this phenomenon, a series of samples were analyzed from two sections at Ximachi in Heqing County, China, which have strong Ti–H signals. The sample ages were obtained using the electron spin resonance (ESR) multiple-centers approach, and the reliability of the ages was validated by comparison with optically simulated luminescence (OSL) ages and between different paramagnetic centers. The ESR data demonstrate that the Ti–H centers can provide accurate dose estimates up to 750–950 Gy, with varying degrees of underestimation at high doses. Combined with previously published Ti–H data, it is evident that the upper threshold of the accurate data obtained from Ti–H centers depends on the sample, and may be positively correlated with the Ti–H/(Ti–Li + Ti–H) ratio (option C/D). According to the provenance significance of the Ti–H/(Ti–Li + Ti–H) ratio, we propose that the Ximachi samples have high Ti–H/(Ti–Li + Ti–H) ratios and then equivalent dose saturation values of Ti–H centers, which may be related to the thermal history of the analyzed quartz grains.</div></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"85 ","pages":"Article 101635"},"PeriodicalIF":1.7,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}