Journal of Asian Earth Sciences最新文献

{"title":"Uncovering the hidden architecture of the Rengali Province, eastern Indian shield using high-resolution aero-geophysics, ground-gravity, structure: Insights towards geology and tectonics","authors":"Debojit Talukdar ,&nbsp;Shuva Sankha Ganguli ,&nbsp;Avisekh Ghosh ,&nbsp;Bijay Kumar Sahu ,&nbsp;Manoranjan Mohanty ,&nbsp;Ashish Kumar Raul","doi":"10.1016/j.jseaes.2024.106416","DOIUrl":"10.1016/j.jseaes.2024.106416","url":null,"abstract":"<div><div>The Rengali Province is a shear zone bounded discrete domain of amalgamation among two Archean Cratons viz. the Singhbhum and Bastar cratons and a mobile belt namely Eastern Ghat Mobile belt. Based on geological evidences, it also displays an India-Antarctica connection in the past geological time-slice and supports supercontinental reconstruction. Although, the tectonothermal evolution of this province has been largely probed based on lithological, structural and metamorphic accounts, however, correlative geophysical-geology integration is absent. Hence, we analyze and interpret newly acquired high-resolution aero-geophysical data for the first time. The interpretations of high-resolution aero-geophysics, ground gravity and radiometric anomaly have been connected with geology to provide insights into tectonic evolution. Multi-scale geological-geophysical-structural<!--> <!-->analysis has been employed for understanding the subsurface architecture and contact relationship with the nearby cratons-mobile belt. Based on the aero-magnetic signature, three different zones have been delineated viz. northern, central and southern zones within the Rengali Province. The three zones are characterized by their distinct geophysical fabric and further are correlated with the geology. The gravity anomaly and modeling suggest the presence of a high-density body at mid-upper crustal depth (∼5–10 km). Three major shear zones, viz. the Barakot, Riamal and Kerajang delineate the bounding surfaces of the Rengali Province. However, the current geophysical signature indicate that the western part of the Kerajang Fault zone (KFZ) shares an inter-domain status between the Rengali Province and the Bastar Craton while the eastern part showcases an intra-domain character. Based on the complex series of magnetic fabric and anastomosing geophysical (particularly, magnetic) signature, the Rengali Province (RP) displays a classical signature of multiple accretionary histories supported by various episodic tectono-thermal activities at different time-slices.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106416"},"PeriodicalIF":2.7,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-Resolution 3D Shear-Wave velocity structure in xiong’an New Area, Beijing (China), revealed by short-period dense seismic array","authors":"Qiaoxia Liu ,&nbsp;Zhiping Xu ,&nbsp;Ming Zhou ,&nbsp;Yonghong Duan ,&nbsp;Yong Qiu ,&nbsp;Chengjun Feng ,&nbsp;Shuaipeng Zhu ,&nbsp;Chongpeng Wang ,&nbsp;Minjie Chen","doi":"10.1016/j.jseaes.2024.106415","DOIUrl":"10.1016/j.jseaes.2024.106415","url":null,"abstract":"<div><div>The 3D shear-wave velocity (Vs) structure in the shallow crustal of Xiong’an New Area can reveal the sediment characteristics and the tectonic features of the blind faults. They are essential for earthquake hazard reduction and geothermal resource exploration in urban areas. The dense array detection method has proved to be an effective technology tool for obtaining the 3D Vs model of the urban area. Using the seismic ambient noise recorded by Xiong’an dense array, we separately conducted the frequency-Bessel transform method and the fast marching technology to estimate short-period (0.4–2.4 s) and long-period (2.5–6 s) fundamental Rayleigh wave phase velocity dispersions. By jointly inverting these dispersions, we finally obtain a fine shallow-deep (0–5 km) 3D Vs model. Our Vs structure correlates well with the tectonic units and reveals the overall stability of the shallow crust structure of the Xiong’an New Area. We extract 3D depths distribution characteristics of the Quaternary and Neogene bottom boundaries from 3D Vs model, which respectively indicates that the Xiongan New Area has been in a relatively stable tectonic position since the Cenozoic. We also provide new evidence to further determine the buried depth and extension patterns of the pre-existing faults or unconformable contact interfaces. Lastly, we analyze and summarize the 3D characteristics of structural sedimentary and potential geothermal exploration areas through conducting comprehensive analysis and interpretation of the regional terrestrial heat flow and geological drilling, which propose a new technical idea for the prospecting and assessing of the geothermal resources based on 3D Vs model.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106415"},"PeriodicalIF":2.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-stage hydrothermal activity affecting the early Jurassic K7 coal seam from the Gaosheng coal Mine, Sichuan Basin, southwest China: Evidence from whole-rock geochemistry and C-O-Sr isotopes in authigenic carbonates","authors":"Rongjie Wang ,&nbsp;Shifeng Dai ,&nbsp;Baruch F. Spiro ,&nbsp;Victor P. Nechaev ,&nbsp;David French ,&nbsp;Ian T. Graham ,&nbsp;Mingxuan Zhou ,&nbsp;Jingjing Liu ,&nbsp;Shaobo Di ,&nbsp;Xiao Tian","doi":"10.1016/j.jseaes.2024.106410","DOIUrl":"10.1016/j.jseaes.2024.106410","url":null,"abstract":"<div><div>Hydrothermal fluid is one of the major sources of elevated concentrations of elements in coals from southwestern China. However, the sources, timing, migration pathways of hydrothermal fluids remain unclear. This study investigated the petrology, mineralogy, elemental geochemistry of whole rocks, and isotope geochemistry (<em>δ</em>¹³C, <em>δ</em>¹⁸O, and ⁸⁷Sr/⁸⁶Sr) of carbonate minerals, to reveal the sources and migration of fluids associated with hydrothermal mineralization within the K7 coal seam from northeastern Sichuan Basin, China. This seam was deposited in an intermontane basin under fresh-water conditions. It contains a complex epigenetic mineral assemblage including carbonates, quartz, pyrophyllite, clay, and minor sulfides and sulfates (gypsum, barite). Syngenetic siderite from the roof and floor mudstones with relatively high ⁸⁷Sr/⁸⁶Sr values (0.710993 and 0.710994) was deposited from fresh water. The <em>δ</em>¹⁸O_VPDB and <em>δ</em>¹³C_VPDB values (from −16.4 ‰ to −13.8 ‰ and from −11.7 ‰ to −8.1 ‰, respectively) of epigenetic calcite and ankerite in the coal indicate their formation from hydrothermal fluids originating from igneous, organic-sedimentary, and, less significantly, marine-carbonate sources. The low ⁸⁷Sr/⁸⁶Sr values (0.708556 to 0.708870) and positive Eu anomaly in coal further indicate the influence of hydrothermal fluids. Elevated Sr/Ba ratios (0.9–1.5) and enriched Ca, Fe, and Mg in the lowermost seam section are attributed to the exfiltration of fluids along coal seam boundaries. The fluids probably penetrated the Mesozoic strata of the northeastern Sichuan Basin through fractures connected with the deep-seated detachment faults. This faulting was associated with Palaeo Pacific-Plate subduction and the Yanshanian post-collisional strike-slip movements in the East China region.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106410"},"PeriodicalIF":2.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial landscape response to active tectonics along the Western Mae Chan Fault, Northern Thailand","authors":"Pichawut Manopkawee ,&nbsp;Niti Mankhemthong ,&nbsp;Weerachat Wiwegwin ,&nbsp;Sathit Kanthata","doi":"10.1016/j.jseaes.2024.106412","DOIUrl":"10.1016/j.jseaes.2024.106412","url":null,"abstract":"<div><div>Mae Chan Fault (MCF) is one of the active faults in northern Thailand, Lao PDR, and Myanmar. Despite fault activeness, the records of recent earthquakes show a lower frequency and magnitude of earthquakes across the MCF than those of the surrounding regions. The morphotectonic analysis evaluates relative tectonic activity based on the drainage systems’ adjustment and geomorphic expressions. We analyzed the Western Mae Chan Fault (WMCF) to explore the spatial response of landscape to relative rock uplift and long-term deformation. We delineated fault segment lines from the remote sensing and the topographic expressions from the digital elevation model. We analyzed the topographic variations from 70 low-order channels developed along the WMCF and evaluated the tectonic activity using geomorphic indices, including the hypsometric integral and hypsometric curve, the standardized stream length-gradient index, the elongation ratio, the drainage basin asymmetrical factor, the mountain front sinuosity, and the valley floor width-to-height ratio. Combining these geomorphic factors with field observations provides the relative indices of active tectonics (RIAT). Our findings revealed that lineament detection from the remote sensing technique indicated the ENE-WSW direction of fault segments. The overall tectonic activity is relatively moderate, but high tectonic activity is present along the western terrain and high topography in the east. The various tectonic activities are consistent with the spatial variations in lineament density and differential rock uplift, where the terrain experienced spatial variations in transtensional and transpressional regimes. This study highlights the potential long-term tectonic activity along the WMCF that dominantly sculpts the modern landscape.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106412"},"PeriodicalIF":2.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithospheric structure beneath Tibet based on gravity data from World Gravity Map 2012","authors":"Jun Li ,&nbsp;Jinxi Li ,&nbsp;Weilin Li ,&nbsp;Zhengwei Xu ,&nbsp;Aidong She","doi":"10.1016/j.jseaes.2024.106411","DOIUrl":"10.1016/j.jseaes.2024.106411","url":null,"abstract":"<div><div>An appreciation of the geodynamics of the Cenozoic great collision between the India and Eurasia plates necessitates an understanding of the lithospheric structure beneath Tibet. Here, we utilise the World Gravity Map 2012 (WGM2012) gravity data to derive the lithospheric density variations and gravity anomaly beneath Tibet, employing the multi-scale inversion and regularised downward continuation methods. The findings indicate that the E-W striking structures persist to a depth of 90 km. The deep lithospheric mantle displays block-like density anomalies that exhibit a distinct N-S trend with increasing depth. The results clearly indicate a decoupling between the lithospheric crust and mantle. It is possible that changes may occur along the Indian plate’s subduction front, which subducts to the south of 32°N along the western portion of the subduction zone, as indicated by the apparent density of the lithospheric mantle. In contrast, in the central and eastern regions, the Indian lithosphere appears to subduct primarily north of the Indus-Tsangbo suture zone (30°N), where it may undergo tearing and delamination beneath the Lhasa block. This phenomenon promotes the convection of soft materials and the upwelling of mantle material, which causes the Tibetan lithosphere to thin and stretch in an E-W direction. At a depth of 150 km beneath central Tibet, alternating lower-density belts trending north–south may be connected at greater depth. These structures likely reflect lithospheric deformation, which plays a crucial role in shaping the geodynamics of the region.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106411"},"PeriodicalIF":2.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogeochemical characteristics of hot springs in the Daju Fault Zone of the SE Tibetan Plateau, China","authors":"Hongzhi Dong ,&nbsp;Xiaocheng Zhou ,&nbsp;Miao He ,&nbsp;Zongjun Gao ,&nbsp;Jinyuan Dong ,&nbsp;Jiao Tian ,&nbsp;Jingchao Li ,&nbsp;Yucong Yan ,&nbsp;Fengli Liu ,&nbsp;Bingyu Yao ,&nbsp;Yuwen Wang ,&nbsp;Zhaojun Zeng ,&nbsp;Kaiyi Liu","doi":"10.1016/j.jseaes.2024.106398","DOIUrl":"10.1016/j.jseaes.2024.106398","url":null,"abstract":"<div><div>Tests on 31 water samples from 10 hot springs within the Daju Fault Zone were conducted to evaluate thermal hydrogeochemical processes in terms of reservoir temperature and depth, circulation length, and relationships with seismic activity. Major elements, trace elements, hydrogen and oxygen isotopes as well as strontium isotopes were analyzed. Results show that the hot spring waters could be sub-divided into nine distinct hydrogeochemical types, receiving recharge primarily from meteoric water and snow-mountain meltwater at elevations ranging between 2262.4 and 4122.1 m above sea level (a.s.l.). Additionally, these springs display a wide range of cold-water mixing ratios (ranging from 60 % to 96 %), reservoir temperatures (ranging between 54.4 and 132.3 °C), as well as circulation depths spanning across a range of values (from 1950.8 to 5337.1 m). Ca²⁺ /Na⁺, Mg²⁺ /Na⁺ and HCO₃^–/Na⁺ ratios suggest that hydrogeochemical processes governing geothermal water composition are controlled by interactions between CO₂-enriched fluids and surrounding lithologies, along with cation exchange. The relationship between Cl⁻ and K⁺, B, Li⁺ indicates their distinct origins from disparate deep fluids. Other elements in hot spring waters of this region are generally originated from rock weathering, and they vary significantly with different geological conditions. Through years of continuous sampling analysis, it has been observed that TDS, HCO₃^–, and (Ca²⁺+Mg²⁺) in hot springs HTX, TSQ, and XG1 exhibit significant variations before and after earthquakes, rendering them highly suitable for investigating the correlation between seismic activity and hydrogeochemistry, whereas CQG excels as the premier option for observing temperature variations caused by seismic activities.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106398"},"PeriodicalIF":2.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Episodic cooling of the Hannan-Micangshan Dome at the northern margin of the Yangtze Block, Central China: Response to progressive convergence in the eastern Tethys since the Mesozoic","authors":"Kui Tong ,&nbsp;Zhiwu Li ,&nbsp;Shugen Liu ,&nbsp;Jinxi Li ,&nbsp;Dong Sun ,&nbsp;Bin Deng ,&nbsp;Wenhui Wu ,&nbsp;Yuehao Ye ,&nbsp;Zijian Wang ,&nbsp;Xun Jiang ,&nbsp;Yin Li ,&nbsp;Xiao Sun","doi":"10.1016/j.jseaes.2024.106409","DOIUrl":"10.1016/j.jseaes.2024.106409","url":null,"abstract":"<div><div>The Hannan-Micangshan Dome (HMD) is a Meso-Cenozoic intra-continental compressional tectonic belt that provides an excellent natural laboratory to study intra-continental deformation processes and geodynamic mechanisms in Central China. Although many low-temperature thermochronological studies have been conducted in the HMD, the timing of initial cooling/exhumation, rapid exhumation phases and their relationship to progressive convergence in the eastern Tethys are still poorly constrained. In this study, we present new multiple thermochronological analyses of apatite (AFT) and zircon fission track (ZFT), hornblende and muscovite Ar-Ar, and zircon U-Pb dating of granitoid and sedimentary rocks from the HMD. Granitoids from the HMD yield Proterozoic zircon U-Pb ages and slightly younger hornblende and muscovite Ar-Ar ages, indicating rapid cooling after emplacement. ZFT dating of granitoids yielded apparent ages of ∼208–140 Ma. AFT dating of Triassic-Cretaceous sandstones and Proterozoic granitoids yielded apparent ages between ∼117 and ∼58 Ma. Thermal modeling results suggest that the HMD has experienced the onset of cooling and exhumation since the Early Jurassic followed by three phases of rapid cooling/exhumation during the Late Jurassic-Early Cretaceous (∼160–100 Ma), Middle Eocene (∼40 Ma) and since the Late Oligocene-Early Miocene (∼23–15 Ma). The initial exhumation in the HMD by the Early Jurassic may be related to the closure of the Paleo-Tethys Ocean between the Kunlun and Qiangtang terranes. The Late Jurassic-Early Cretaceous rapid exhumation in the HMD can be related to the basement-involved thrusting triggered by the far-field effects of the ongoing collision between the Qiangtang and Lhasa terranes following the closure of the Meso-Tethys since the Late Jurassic. Two phases of rapid Cenozoic exhumation by the Middle Eocene and since the Late Oligocene-Early Miocene in the HMD were attributed to the far-field stress effects of the collision between the India and Asian plates and the lateral growth of the Tibetan Plateau. Therefore, we proposed that the episodic cooling since the Early Jurassic of the HMD at the northern margin of the Yangtze Block can be interpreted as being related to the progressive convergence in the eastern Tethys since the Mesozoic.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"278 ","pages":"Article 106409"},"PeriodicalIF":2.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A study of crustal deformation beneath the Qinling Orogenic belt, Central China based on receiver function data","authors":"Ya Sun ,&nbsp;Yangyi Deng ,&nbsp;Syed-Muzyan Shahzad ,&nbsp;Bo Chen","doi":"10.1016/j.jseaes.2024.106404","DOIUrl":"10.1016/j.jseaes.2024.106404","url":null,"abstract":"<div><div>A joint shear wave splitting technique based on receiver function data is employed to invert the crustal anisotropy, Moho depth, and Vp/Vs ratio in the Qinling Orogenic belt (QOB). Our findings reveal a relatively low Vp/Vs ratio (∼1.74) and a thin crust in east QOB. This suggests that potential crustal flow from central Tibet may not significantly influence the crustal deformation in east QOB. Our results demonstrate high Vp/Vs ratios (∼1.75–1.88), thick crust (∼44–56 km), and significant crustal anisotropy with a delay time of 0.22–0.86 s in south QOB, Dabashan, and west QOB regions. The fast directions of crustal anisotropy in the south QOB and Dabashan areas are NW-SE, which reflect the orientation of crustal fabrics associated with the collision between the North China Block and the South China Block. However, weak or negligible splitting times are observed beneath the Shennongjia-Huangling (SNHL), Hannan-Micang (HNMC) domes, and Jianghan Basin. The presence of weak crustal anisotropy is likely related to the stable basements beneath two domes, while the negligible splitting time beneath the Jianghan Basin might be attributed to the nearly vertical α-axis of olivines or mica associated with a subvertical mantle flow caused by slab break-off of the subducted Yangtze Block. The underlying magmas have gathered in the lower crust and formed the mafic lower crust, which cause an increase in the crust Vp/Vs ratio and crustal extension.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"277 ","pages":"Article 106404"},"PeriodicalIF":2.7,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zircon and garnet U-Pb dating reveals the mineralization history of volcanic-related skarn iron deposits","authors":"ZhiYuan Sun ,&nbsp;MingLiang Wang ,&nbsp;YongGang Sun ,&nbsp;XiaoQiang Zhu ,&nbsp;Tao Yang","doi":"10.1016/j.jseaes.2024.106401","DOIUrl":"10.1016/j.jseaes.2024.106401","url":null,"abstract":"<div><div>The genesis of skarn garnet in volcanic-related skarn iron deposits is controversial because of the absent or ambiguous spatiotemporally related intrusions. In this study, we present combined LA-ICP-MS garnet U-Pb and SHRIMP zircon U-Pb ages to determine the spatiotemporal relationship between skarn garnet and a potentially related intrusion or causative volcanic rock. Three types of garnet (Grt1, Grt2, and Grt3) are identified in the Yamansu deposit, and Grt1 yields a lower intercept age of 326 ± 9 Ma (n = 32, MSWD = 0.3). SHRIMP zircon U-Pb dating of the associated volcanic rock yields a weighted mean age of 327 ± 3 Ma (n = 10, MSWD = 1.4), suggesting an isochronous relationship between the volcanic rock and Grt1. Grt2 and Grt3 yield lower intercept ages of 316 ± 6 Ma (n = 22, MSWD = 1.4) and 315 ± 6 Ma (n = 35, MSWD = 1.5), respectively. However, the zircon U-Pb weighted mean age of 252 ± 4 Ma (n = 5, MSWD = 0.8) obtained from the associated intrusion is obviously younger than the skarn age and the previously reported ore-forming age, implying no temporal relationship between mineralization and the intrusion. More significantly, precise ²⁰⁶Pb/²³⁸U weighted mean ages of 325 ± 9 Ma (n = 15, MSWD = 0.3), 316 ± 8 Ma (n = 11, MSWD = 0.4), and 319 ± 7 Ma (n = 12, MSWD = 0.5) were obtained from Grt1, Grt2, and Grt3, respectively, and we find that andradite-rich garnet with high U and ΣREE concentrations has the potential to yield the more precise U-Pb ages. The combined garnet and zircon U-Pb ages reveal that the hydrothermal skarn and mineralization in volcanic-related skarn iron deposits are related to volcanic activity rather than intrusions. Multiple episodes of volcanic-related hydrothermal activity may have caused multiple phases of skarn formation and mineralization in volcanic-related skarn iron deposits.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"277 ","pages":"Article 106401"},"PeriodicalIF":2.7,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rock-ice avalanche-generated erosion behaviors at the Sedongpu gully, Tibet, China: New insights from the geomorphologic perspective","authors":"Tiantian Zhang ,&nbsp;Kai He ,&nbsp;Bin Li ,&nbsp;Yueping Yin ,&nbsp;Haoyuan Gao ,&nbsp;Shaohua Gao","doi":"10.1016/j.jseaes.2024.106403","DOIUrl":"10.1016/j.jseaes.2024.106403","url":null,"abstract":"<div><div>In recent years, massive rock-ice avalanches frequently occur in the Sedongpu gully, forming an extensive dammed lake. Rock-ice avalanches not only threaten residents living in upstream and downstream areas, but also significantly change geomorphology. The gully geomorphology also experienced complicated alterations, due to distal motion distance and strong entrainment of debris flows, coming from the conversion of rock-ice avalanches. This study aims to determine the relation between dynamics erosion of rock-ice avalanches and geomorphology evolution during rock-ice avalanche events at the Sedongpu gully, where a large amount of moraine was distributed with five branch ditches. Field investigations, digital elevation models (DEMs), unmanned aerial vehicles (UAVs), multiphase remote-sensing images, topographic profiling, and InSAR monitoring are carried out to characterise the material changes, including composition, structure, transition, and deposits. Materials were entrained and scraped by debris flows and transported into the Yarlung Zangbo River. The total erosion volume of materials on the valley floor reached 980 million m³ from 2010 to 2021. Topographical profiling suggests that the most severe erosion also occurred in the midstream Sedongpu gully, with the maximum width of above 500 m. The overall elevation of the downstream valley increased by 50 m due to continuous deposits, and formed a large debris fans. The results might be helpful in further studies to reveal dynamic erosion geomorphology of rock-ice avalanches.</div></div>","PeriodicalId":50253,"journal":{"name":"Journal of Asian Earth Sciences","volume":"277 ","pages":"Article 106403"},"PeriodicalIF":2.7,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}