Landslide-damming events, occurred frequently in Southeastern margin of the Tibetan Plateau, often can be served as valuable geological records for reconstructing tectonic activities and understanding river evolution processes. The Ninglang paleo-landslide, situated on a branch fault of the Chenghai Fault Zone in Ninglang County of China, exemplifies such phenomena. This study combined field investigations, UAV photogrammetry and dating methods to analyze the characteristics, formation mechanism and evolutionary process of this landslide damming event. The results show that the Ninglang paleo-landslide with an estimated volume of 3.7 × 10⁷ m3 was triggered by seismic activity. The landslide formed one about 70 m high dam to create a dammed lake with a covered area of approximately 2.84 × 10⁶ m2, significantly changing the local geomorphology. According to the dating results, the dammed lake could be formed from at least 33.1 ka BP and breached at about 0.05 ka BP, which indicated that the dam kept over 33 ka. The failure mechanism is attributed to a branch of the Chenghai Fault, which crossed the landslide area. Fault movement created a weak structural zone within the dam body, which became a preferential flow path for water. This concentrated erosion initiated piping, a process that was accelerated by the warm and humid conditions of the Holocene Climate Optimum, ultimately leading to the dam's breach. The findings in this study provide valuable insights for similar landslides and contribute to a more comprehensive understanding of landslide-induced landscape evolution of river catchments.

Recrystallized carbonates formed on fault surfaces via fault activity and calcite veins in fault zones are promising dating materials for geochronological studies using methods such as electron spin resonance (ESR) dating. However, the bleaching characteristics and thermal stability of ESR signals in these materials have not been previously reported. In this study, three carbonates associated with fault activity (recrystallized carbonate, calcite vein, carbonate bedrock) were collected to investigate their bleaching characteristics and thermal behavior. The results of bleaching experiments show that the bleaching characteristics exhibit two patterns. Of seven observed signals, four were completely bleached by sun-like light exposure (g = 2.0040, g = 1.9995, g = 2.0057, g = 2.0018) in order of decreasing sensitivity to light. The other three signals (g = 2.0006, g = 2.0022, g = 2.0031) could not be fully zeroed, and their signal intensities reached stable residual values after different exposure times depending on the signal. The results of thermal annealing experiments show that the observed signals intensities decreased in the three samples during annealing, except the g = 2.0057 line. The g = 2.0006 line is the most promising for ESR dating on account of its stable thermal behavior and low sensitivity to optical bleaching. Lastly, the g = 2.0040 signal shows thermal instability, and caution is required when using this signal for dating.

The chronology of fault activity in bedrock is critical to constraining and understanding periods of active faulting, assessing seismic hazards, and mitigating the effects of earthquakes. However, because of the lack of suitable materials for dating, the temporal reconstruction of faulting in bedrock remains highly challenging for geologists. In the present study, we determine for the first time the electron spin resonance (ESR) ages of fault barite (BaSO4), which is produced by episodes of intense faulting on basalt bedrock fault surfaces. Three barite samples were obtained from a basalt fault section (27 degrees 5 ' 23 '' N, 100 degrees 25 ' 45 '' E, 1.8 km above sea level) of the Lijiang-Xiaojinhe Fault (LXF), southeastern Tibetan Plateau, for ESR measurements. Similar to marine barite, the ESR spectrum of fault barite shows an electron-type center with g = 2.0037, 2.0034, and 2.0028 attributed to SO3-. The signal intensity systematically increased with increasing gamma-ray dose. Dose rates were calculated using a model based on the location and burial depth of the barite samples, as well as their surrounding bedrock. The three barite samples yield ESR ages of 131 +/- 26, 503 +/- 61, and 1416 +/- 246 ka, respectively, which indicate that the LXF was active during the Early and Middle Pleistocene. The three ESR ages for fault barite from basalt extend the time range of activity of the LXF compared with previous carbonate ESR and radiocarbon dating results. Consequently, we propose that ESR dating of barite is valuable for reconstructing the history of bedrock fault activity. However, given that this investigation represents a preliminary application of the fault-barite ESR method, further study is needed to confirm its usefulness and the accuracy and precision of dating results.

It is very important to distinguish the strata of different periods in the Quaternary period, especially the Middle Pleistocene and Late Pleistocene strata, for stratigraphic division, depositional environmental analysis and climate evolution analysis. In this study, the Shinaimiao (SNM) borehole sequence in Hebi City, Henan Province (China) was established by both electron spin resonance (ESR) and magnetostratigraphy methods. Both Al (eighteen samples) and Ti-Li (eight out of the eighteen samples) centers were measured using the Multiple Aliquots Additive Dose (MAAD) method. In addition, hundreds of magnetostratigraphic samples were measured to determine the precise position of the Matuyama/Brunhes (M/B) boundary. The results show that: (1) The equivalent dose (DE) values of the Al and Ti-Li centers are consistent within the error range, demonstrating that the Multiple Center (MC) approach has worked. (2) The ESR dating results are consistent with the order of sedimentation (the ages get older with depths) and with magnetostratigraphic results of the B/M boundary within the error range, indicating that the ESR ages obtained from the Al and Ti-Li centers are reliable in this study. (3) By comprehensive analysis of the dating results and lithology characteristics, the stratigraphic ages of the SNM borehole with a depth of 126.93 m spans from Neogene to Holocene, but part of the early Pleistocene strata are missing.

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.

Assessing the adequate bleaching of quartz Electron Spin Resonance (ESR) signals at the time of deposition is essential for sediment ESR dating. In this study, we focus on the Datong volcanic group is situated in Datong City, Shanxi Province, and is among the most renowned volcanic groups in China. The eruption within the Datong volcanoes during a geological period resulted in extensive high-temperature lava flow that directly overlaid Quaternary lacustrine deposits and subjected the underlying lacustrine layers to high-temperature heating. Thus, an investigation of the field profile in the Yujiazhai area, southeast of the Datong Volcanic Group, shows a novel approach for assessing the bleaching extent of ESR centers. This is accomplished by comparison of the D E values of the Al and the Ti -Li centers in partly-heated layer sample. The result reveals that quartz Al and Ti -Li centers in the lacustrine sediments appear to undergo sufficient bleached during transportation and natural bleaching processes in the study area. Furthermore, this study provides insight into the chronology of volcanic eruption in the Yujiazhai area, estimating an eruption age of approximately 300 ka. This volcanic activity most likely corresponds to the third volcanic activity period in the Datong region.

The electron spin resonance (ESR) method has been successfully applied to dating hydrothermal barite; however, there have been few studies of modern continental barite, such as that generated by fault movement or in sedimentary deposits. To better understand the geological processes involved in the formation of continental barite, its thermal characteristics and age firstly need to be defined. In this study, one fault barite sample and two sedimentary barite samples were obtained from continental sites in China for ESR signal thermal stability experiments. Microwave -power experiments indicate that 0.5 mW produces the maximum ESR signal intensity and the highest signal-to-noise ratio. Stepwise -heating results reveal that ESR signal intensities remain stable below 100 degrees C then show an increasing trend that peaks at -180 degrees C, following which they decrease rapidly between 180 and 320 degrees C and disappear at -380 degrees C. Isothermal heating results show that ESR signal intensities remain stable within a temperature range of 100 - 200 degrees C but show a decreasing trend for temperatures of 240 - 320 degrees C. These results indicate that the thermal decay of the ESR signal intensity for the three studied continental barites follows second -order decay kinetics. The thermal lifetimes calculated for the three samples are 6.3 x 10 8 , 7.5 x 10 7 , and 8.7 x 10 6 a, respectively. Thus, barite ESR dating can be used to date related geological events since early Pleistocene.

The chronology study of river terraces is important to reconstruct the history of regional climate change and tectonic uplift. Due to greater signal dose saturation levels, electron spin resonance (ESR) dating became as a potentially powerful tools for the chronology of Middle Pleistocene terraces. In this study, two profiles of terrace fluvial sediments from the Sanggan River Canyon were dated using quartz Ti-Li center ESR method. The ESR dating results show that the terraces T3 to T6 were formed at 125 +/- 16 ka, 181 +/- 20 ka, 315 +/- 31 ka and 379 +/- 44 ka, respectively. T1 and T2 were formed at 7 +/- 0.3 ka and 43 +/- 4 ka respectively obtained from optically stimulated luminescence (OSL) dating. These are among the first numerical ages obtained for such high terraces in the Nihewan Basin. The present work contributes to establish the chronological framework of the Late Middle Pleistocene and Holocene terraces of the Sanggan river and to improve the Quaternary stratigraphy of the Nihewan Basin.

第四纪碎屑沉积物是新构造运动和第四纪地质环境变化的重要信息载体.对第四纪碎屑沉积物,尤其是对距今 200ka以上不含火山灰的粗颗粒样品(如砾石堆积)进行测年,一直是第四纪年代学研究中的重点和难点问题,石英 ESR 测年法是能够直接测定这类样品的测年方法之一.但是,将石英 ESR法测年应用于早更新世沉积物(特别是粗颗粒沉积)结果的可靠性国内外至今鲜有报道,是目前亟待解决的年代学问题之一.文中基于石英 ESR法测年原理和前人的研究成果,以已知年龄的下更新统靖远砾石层为研究对象,探讨了早更新世砾石堆积石英 ESR法测年的可靠性.结果显示:1)靖远砾石层石英 Ti-Li心在 11 000Gy附加剂量范围内 ESR信号未饱和,Al心在 13 000Gy附加剂量范围内 ESR信号未饱和;2)单饱和指数函数和"指数+线性"函数可分别为 Ti-Li心和 Al心提供更优的等效剂量拟合结果,且拟合效果均优于 0.98;3)靖远砾石层石英 Ti-Li心和 Al心的平均ESR测年结果分别为(1.67±0.15)Ma和(1.65±0.69)Ma,与已知的宇生核素测年结果(约为(1.73±0.13)Ma)和岩石地层结果在误差范围内是一致的.综上所述,石英 Ti-Li 心和 Al 心 ESR法测年均可为早更新世含砂质透镜体的砾石层堆积提供可靠的年代学数据.

Residual doses may cause overestimation of electron spin resonance (ESR) ages for fluvial sediments. However, ESR residual doses in outburst megaflood sediments have rarely been evaluated. The Jinsha River, situated in the southeastern Tibetan Plateau, is characterized by active faults, narrowed canyons, and dammed lakes. Consequently, the river is a rare opportunity for a reconstruction study of outburst flood events from a paleo-dammed lake. After the destruction of the Baige dammed lake in the upper Jinsha River in 2018, outburst megafloods formed a thick diluvium that was deposited in broad valley land along the lower Jinsha River. Based on detailed field investigation and laboratory studies, preliminary hydraulics estimates and residual quartz ESR signals indicate the following. 1) Among the multiple quartz ESR centers, the Al, E 1 ʹ, Ti-H, and Ti-Li centers could be measured. The Ti-H center had the lowest residual dose and would provide relatively accurate ages for outburst megaflood sediment. 2) The Ti-Li and Al centers commonly used for ESR dating provide overestimates of 283 ± 42 ka ∼ 462 ± 63 ka and 1,010 ± 88 ka ∼ 1,400 ± 219 ka, respectively, for present outburst megaflood sediment. 3) The diverse ages given by the same ESR signal may be caused by various precursors of megaflood sediments, which are mainly sourced from landslide dams and from various terraces and slope sediments along the river. Results demonstrated that the apparent ESR ages observed for the outburst megaflood sediment in the southeastern Tibetan Plateau may be counterfeit, providing an age much older than its real age. This could be interpreted to mean that the narrowed lower channel makes the upper reaches of the broad valley appear lake-like, with diluvium deposits having large non-negligible residual ESR signals without enough exposure to adequate sunlight, despite having good stratification and sorting characteristics similar to those of fluvio-lacustrine sediments. Thus, abrupt reversal in quartz ESR ages in multiple centers observed in the geochronological framework of the fluvial sedimentary profile may indicate a diluvial or flood layer in the absence of other inducements.

Determining occurrence age is key to chronology analysis of huge landslides. However, in carbonated bedrock areas, it is difficult to carry out geochronological surveys of landslide evolution due to lack of suitable dating materials and methods. In carbonated bedrock areas, the cosmic nuclides 36Cl and 14C dating methods have been used for obtaining the exposed age of bedrock. But intense weathering, erosion and dissolution make it difficult to obtain an accurate total amount of cosmogenic nuclide accumulation, resulting in the dating results being affected greatly by weathering, erosion and dissolution of carbonate rock. Therefore, it is necessary to find new dating materials or methods for determining the occurrence age of landslide in carbonate bedrock areas with little quaternary sediments. In this study, a huge landslide developed in the carbonate bedrock area of south eastern Tibet is introduced briefly, which is named the Qiaojia landslide and blocked the Jinsha River. A thin layer including three obvious recrystallized carbonate sub-layers was formed in the sliding zone, indicating different sliding events. Three recrystallized carbonate samples were then collected for ESR dating research to obtain the age information of the Qiaojia landslide: one occurred 79 +/- 8 ka years ago, and the other occurred 60 +/- 10 ka years ago, and the third occurred 25 +/- 2 ka years ago, which are in general agreement with other studies in the surrounding of the study area. It suggests that recrystallized carbonate on sliding face is suitable for chronologically identifying landslide activity by using ESR method in the carbonate area, especially in the areas with little or no quaternary sediments.

The investigation of irradiation sensitivity of electron spin resonance (ESR) centers is a significant part of the study of ESR signal characteristics and helps to gain insight into the physical mechanisms of paramagnetic centers. In this study, we have observed and compared the irradiation sensitivity characteristics of ESR centers under high-temperature baking in natural conditions by lava flow. Results show that the irradiation sensitivity of the Al and Ti-Li centers increases with the baking temperature, while the irradiation sensitivity of the Ti-H center increases first (up to similar to 500 degrees C) and then decreases with temperature. Moreover, the ESR intensity of the Ti center is more strongly dependent on the annealing history of the samples than the Al center. In addition, from the results of the heating experiment, after heating above 1000 degrees C, additional irradiation does not produce new Ti-H signals, which probably indicates that the paleo-temperature of the lava flow in Yujiazhai area did not exceed 1000 degrees C.

前人研究结果表明不同人工辐照剂量率会影响石英的ESR信号强度,但是人工辐照剂量率的差异是否会对碳酸盐材料的ESR信号强度产生影响还未见相关报道.本文以采自云南剑川盆地龙门邑地区的一块钙华手标本样品为研究对象,选择5个不同的剂量率(40Gy/h、400 Gy/h、2000 Gy/h、4000 Gy/h和5400 Gy/h)对样品分别进行人工附加剂量(1000 Gy、2000 Gy和3000 Gy)辐照,观察分析钙华ESR信号(g=2.0006、g=2.0040和g=2.0057)强度对不同人工辐照剂量率的响应.实验结果表明:小剂量率人工辐照时,特征ESR信号强度普遍更强,能获得稳定的等效剂量,且辐照误差小;而大剂量率人工辐照时,特征ESR信号强度较弱,获得的等效剂量较不稳定,且辐照误差大.因此,在钙华ESR测年应用中,建议尽可能选择较小剂量率进行人工辐照,同时放入剂量片以便准确地计算实际辐照剂量.

近年来，石英ESR信号强度在风成沉积和河流沉积中都已被证明为一种行之有效的物源示踪指标。文章以长江流域干流不同河段及其主要支流为研究对象，共采集20个现代河流沉积物样品，对其粒度组成特征及其石英自然E′ 1 心，辐照5000 Gy的Al心、 Ti心的ESR信号强度空间分布特征及其物源示踪意义进行了探讨，主要取得了以下初步认识：1)长江流域沉积物从上游地区到中下游地区经历了长时间、长距离的搬运，经过了充分的混合，且呈现“沿程细化”之趋势；本研究的长江流域干流河段及其主要支流（河漫滩及江心洲）的沉积物主要以125～500μm的粒径组分为主，约占全样组分的60%～90%（平均为80%）。2)从上游河段到中下游河段，长江主要支流和干流不同河段沉积物石英自然E′ 1 心，辐照后的Al心和Ti心ESR信号强度都表现出了较好的空间分异性，即上游河段处于低端元值域而下游河段处于高端元值域。3)长江上游地区以及汉江是长江中下游干流沉积物的主要贡献者，而中下游地区的鄱阳湖水系和洞庭湖水系对长江干流物质的贡献度非常低。

Determining the upper dating limits of electron spin resonance (ESR) signals is essential to assess the reliability of ESR ages. Saturation and thermal lifetime are mainly factors that constrain the upper dating limit of ESR signals. In this study, we investigated the saturation dose (D0) and thermal lifetime of the signal at g = 2.0006 in recrystallized carbonates produced by faulting, which is accepted to be the most reliable ESR signal for dating of carbonates, to determine the upper dating limit of this signal. The D0 was obtained by establishing the doseresponse curves on irradiation. Among the four fitting functions (SSE, DSE, EXP + LIN, and Dgamma), the EXP + LIN function provide the best approximation to the data points. Consequently, the D0 range is around 1100-2600 Gy, which limits the reliable equivalent dose (DE) range to about 350-900 Gy for this signal. Thus, by dividing the maximum DE and the dose rate, we obtained an upper dating limit of 0.9-2.3 Ma for this signal derived from the D0. Annealing experiments show that the ESR signal at g - 2.0006 contains two components with different thermal stability, one of which has a short lifetime of around 20 ka (20 degrees C), while the other has a long lifetime of similar to 8 Ma (20 degrees C). In summary, after taking into account both saturation dose (D-o) and lifetime, the upper dating limit of this signal in recrystallized carbonates is about 1 Ma.

The Yinchuan Basin, one of the most important basins in the area adjacent to the northeastern Tibetan Plateau, contains a continuous sequence of fluvio-lacustrine deposits, which makes it an ideal area to study the in-teractions between the Tibetan Plateau uplift, climate change, and geomorphological evolution. Here, a 1200-m -deep drill core (YNZK01) is described with an average recovery rate of 96% in the depo-center of the Yinchuan Basin to establish a high-resolution palaeoenvironmental and tectonic reconstruction. Stepwise alternating-field demagnetization results showed a stable and high-qualified remanent magnetization of the samples. The polarity sequences consisted of 8 normal and 8 reverse zones that correlate well with the geomagnetic polarity timescale. Magnetostratigraphic results date the entire YNZK01 core from 3.927 Ma to the present. The B/M boundary (0.781 Ma) is at a depth of 246.4 m while the M/G boundary (2.581 Ma) is at a depth of 863.4 m. The G/Gi boundary (3.596 Ma) is identified at 1117.8 m and the bottom of the core was extrapolated to 3.927 Ma (1201 m) with an average sedimentation rate of 863.4-1117.8 m. This high-resolution magnetostratigraphy record pro -vides a baseline chronological framework for further research and publications on the tectonic, paleoclimatic, and paleoenvironmental proxy data of the YNZK01 core in the Yinchuan Basin, NE Tibetan Plateau.

泥河湾盆地因发育良好的晚新生代湖相地层、丰富的旧石器遗址和哺乳动物化石而广受关注.盆地内已发现旧石器遗址100余处,被学术界称为"东方奥杜韦(Olduvai)峡谷".由于缺乏合适的年代测定方法,许多重要的遗址,尤其是中更新世时间段的遗址缺乏年龄数据,如三棵树遗址,使得旧石器遗址研究少了时间轴合理的年代学框架.电子自旋共振(ESR)测年技术是上世纪60年代发展起来的一种测年技术,并在实践中得到了地质学界的广泛认可.对于中更新世遗址年龄的测定,ESR测年法具有明显的优势.本文利用石英Ti-Li心ESR法对三棵树遗址沉积物样品进行了独立年代测定,得到三棵树遗址文化层的年龄为599±70kaBP.该年龄对于了解泥河湾盆地古人类的生存演化提供了必要的年代学依据.

The Nihewan Basin is one of the most important areas for the study of early human evolution and land mammals in East Asia. More than 100 Paleolithic sites have been discovered in the basin, spanning the Early Pleistocene to the Late Pleistocene. The chronological framework for the Early Pleistocene sites is well established using magnetostratigraphy. However, few independent ages are associated with Middle Pleistocene sites; one such example is the Hougou Paleolithic site, where interpolated magnetostratigraphic ages are not precise and ac-curate enough, owing to the artifact layer of the site is far relative to the Matuyama/Brunhens (M/B) boundary. In this study, we use the ESR signals of Al and Ti-Li centers in quartz to date the Hougou site. The advantages of the regenerative dose method over the additive dose method were discussed. Our ESR results indicate that the age of the Hougou Paleolithic site is between 436 +/- 30 and 416 +/- 42 ka, approximately with an average of 426 +/- 36 ka, which corresponds to Marine Isotope Stage (MIS) 12 or loess layer L5. In addition, the disappearance time of the eastern part of the Nihewan paleolake may be approximately 430 ka.