Journal of Asian Earth Sciences最新文献_第2页

Depositional environments of a mixed siliciclastic-carbonate system: A case study of the late Ediacaran sedimentary succession in the northern Sichuan Basin (SW China) 硅-塑-碳酸盐岩混合体系沉积环境——以四川盆地北部晚埃迪卡拉世沉积演替为例

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-29 DOI: 10.1016/j.jseaes.2025.106942

Junxin Shang , Mingyou Feng , Xingzhi Wang , Maolong Xia , Yong Li , Junlang Chen , Chao Zhang , Xiaohong Liu

The limited understanding of late Ediacaran mixed carbonate-siliciclastic sedimentary systems in the northern Sichuan Basin poses challenges for reconstructing the paleogeographic configuration. This study investigated outcrops of the Labagang and Dengying Formations in the region to develop a depositional model and identify controlling factors. Detailed sedimentological observations led to the identification of eleven lithofacies dominated by rimmed platform deposits and eight lithofacies dominated by siliciclastic-rich platform deposits, which were grouped into six facies associations, representing two distinct sedimentary models: rimmed platform and siliciclastic-dominated platform. Based on sedimentological analysis, log datasets, and chronostratigraphic data, two third-order sequences with transgressive systems tract (TST) and highstand systems tract (HST) were established. During TST1 and TST2, the Labagang Formation and the third member of the Dengying Formation were dominated by siliciclastic-rich deposits, classified into inner platform, middle platform, and outer platform facies associations. These sequences were interpreted as representing two separate flooding events that affected the depositional architecture and facies distribution of the platform. In contrast, during HST1 and HST2, the second and fourth members of the Dengying Formation were primarily composed of carbonate-rich deposits, categorized into peritidal to lagoon, microbialite reef complex, and slope to siliceous basin facies associations, associated with a slow sea-level fall following transgression. These third-order sequences, primarily controlled by regional sea-level changes, may also reflect episodic tectonic activity. Sustained plate convergence likely reactivated fault-related structures inherited from earlier rifting, leading to regional subsidence and flooding events.

四川盆地北部晚埃迪卡拉世碳酸盐-硅屑混合沉积体系的认识有限，给古地理构型的重建带来了挑战。通过对该地区拉巴岗组和灯影组露头的研究，建立了沉积模式，并确定了控制因素。通过详细的沉积学观察，确定了以边缘台地沉积为主的11个岩相和以富含硅屑碎屑台地沉积为主的8个岩相，并将其划分为6个相组，代表了两种不同的沉积模式：边缘台地和硅屑碎屑台地。根据沉积学分析、测井资料和年代地层资料，建立了海侵体系域（TST）和高位体系域（HST）两个三级层序。TST1和TST2期间，拉巴岗组和灯影组三段以富硅屑沉积为主，分为内台地、中台地和外台地相组合。这些层序被解释为代表了两个独立的洪水事件，影响了台地的沉积构型和相分布。而在HST1和HST2时期，灯影组二段和灯影组四段主要为富碳酸盐沉积，分为潮滩-泻湖相、微生物岩礁复合体和斜坡-硅质盆地相组合，并伴有海侵后缓慢的海平面下降。这些三级层序主要受区域海平面变化控制，也可能反映幕式构造活动。持续的板块收敛可能重新激活了从早期裂陷中继承下来的与断层有关的构造，导致了区域下沉和洪水事件。

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引用次数: 0

Precambrian crustal evolution of the southern margin of the North China Craton: Evidence from the Paleo–Mesoproterozoic sedimentary rock 华北克拉通南缘前寒武纪地壳演化：来自古-中元古代沉积岩的证据

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-29 DOI: 10.1016/j.jseaes.2025.106943

Shuo Wang , De-Bin Yang , Xiang-Yu Yan , Ke Wu , Jian-Ning Liu , Rui-Qing Xue

Clastic sedimentary rocks offer crucial insights for deciphering the Precambrian crustal evolution. Paleo–Mesoproterozoic sedimentation is widely developed in the southern margin of the North China Craton (SNCC). Previous research has primarily concentrated on magmatism, while the information of Precambrian crustal evolution revealed by sedimentary rocks was less concerned. Hence, we present the zircon U–Pb ages, zircon Hf isotopes and whole-rock geochemical data of the quartz sandstones from the Beidajian Formation of the Ruyang Group, the Sanjiaotang Formation of the Luoyu Group and the Ma’anshan and Luotuopan formations of the Wufoshan Group within the SNCC. The detrital zircon dating, Hf isotope data and geochemical features of these formations indicate that their sediments were primarily sourced from the Neoarchean–Paleoproterozoic rock units in the SNCC, with the characteristics of mature crustal materials. Their detrital zircon age spectra and depositional environment combined with geological evidence indicate that the SNCC was in an extensional environment during the late Paleoproterozoic to early Mesoproterozoic. The Hf isotope data combined with geological evidence suggest that the crustal growth was dominant in the SNCC during the early Neoarchean (2.80–2.70 Ga), and the crustal reworking played a dominant role during the mid- to late Paleoproterozoic (2.00–1.72 Ga), while the crustal growth and reworking coexisted during the late Neoarchean (ca. 2.50 Ga) and early to mid-Paleoproterozoic (2.46–2.02 Ga).

碎屑沉积岩为破译前寒武纪地壳演化提供了至关重要的见解。华北克拉通南缘古-中元古代沉积广泛发育。以往的研究主要集中在岩浆活动方面，沉积岩揭示的前寒武纪地壳演化信息较少。在此基础上，给出了北洋群北大尖组、罗屿群三角塘组、五佛山群马鞍山组和骆驼滩组石英砂岩的锆石U-Pb年龄、锆石Hf同位素和全岩地球化学数据。碎屑锆石定年、Hf同位素数据和地球化学特征表明，这些地层的沉积物主要来自SNCC的新太古代-古元古代岩石单元，具有成熟的地壳物质特征。其碎屑锆石年龄谱和沉积环境结合地质证据表明，在古元古代晚期至中元古代早期，SNCC处于伸展环境。Hf同位素资料结合地质证据表明，SNCC在新太古代早期（2.80 ~ 2.70 Ga）以地壳生长为主，在古元古代中晚期（2.00 ~ 1.72 Ga）以地壳改造为主，而在新太古代晚期（约2.50 Ga）和古元古代早期至中期（2.46 ~ 2.02 Ga）地壳生长和改造同时存在。

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引用次数: 0

SHRIMP U-Pb zircon ages and geochemistry of Jian forsterite jade from Jilin province, North-eastern China 吉林省剑长石玉石SHRIMP U-Pb锆石年龄及地球化学特征

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-28 DOI: 10.1016/j.jseaes.2025.106944

Bijie Peng , Mingyue He , Mei Yang , Ning Wang

The Jian forsterite jade, a recently discovered gemological variety from Northeast China, is characterized by attractive coloration and fine-grained texture. The formation age and ore-forming materials provenance of the jade deposit remain unconstrained, posing significant obstacles to understanding its genesis. In this study, we conducted petrography, whole-rock geochemistry, and zircon U-Pb geochronology analyses of Jian forsterite jade using X-ray fluorescence spectroscopy (XRF), Laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), and Sensitive High-Resolution Ion Micro Probe (SHRIMP). The whole-rock geochemical data show high MgO contents with relative depletion in Cr, Co, and Ni. The chondrite-normalized REE patterns, characterized by LREE enrichment and HREE depletion, closely resemble those of marble, supporting a protolith of magnesium-rich dolomitic marble. Boron isotope compositions of forsterite (5.11 ‰–6.91 ‰) from the Jian forsterite jade overlap with that of boron-rich minerals from adjacent boron deposits, indicating that the source of boron is related to the enrichment of boron in the Paleoproterozoic Ji’an Group strata. SHRIMP U-Pb dating of zircons from the Jian forsterite jade yield concordant ages of 420.4 ± 8.6 Ma to 439.4 ± 8.8 Ma, which provide a maximum age constraint for the formation timing of the jade deposit. Based on the geochemical and geochronological evidence, we propose that the Jian forsterite jade deposit is of hydrothermal metasomatic origin. During the prograde metamorphism, silica-rich hydrothermal fluids reacted with the Mg-rich carbonates to form forsterite. Subsequently, forsterite was metasomatized by boron-rich fluids, which induced different degrees of serpentinization, ultimately generating the Jian forsterite jade deposit.

摘要近年来在中国东北地区发现的一种宝石品种——坚橄榄石玉，具有色泽鲜艳、纹理细腻的特点。玉石矿床的形成年代和成矿物质来源尚无定论，对其成因的认识存在较大障碍。本文采用x射线荧光光谱（XRF）、激光烧蚀多集电极电感耦合等离子体质谱（LA-MC-ICP-MS）和高分辨率离子微探针（SHRIMP）等技术，对剑锋石玉石进行了岩石学、全岩地球化学和锆石U-Pb年代学分析。全岩地球化学数据显示MgO含量高，Cr、Co、Ni相对富集。球粒陨石归一化稀土模式与大理岩相似，表现为轻稀土富集和重稀土亏缺，支持富镁白云质大理岩原岩。吉安岩体玉石中富硼矿物硼同位素组成（5.11‰~ 6.91‰）与邻近硼矿床富硼矿物硼同位素组成重叠，表明硼的来源与古元古代吉安群地层中硼的富集有关。对剑山橄榄石玉石锆石SHRIMP U-Pb定年结果显示，锆石年龄在420.4±8.6 ~ 439.4±8.8 Ma之间，为该玉石矿床的形成时间提供了最大年龄约束。综合地球化学和年代学的证据，认为吉安森林石玉石矿床为热液交代成因。在进变质作用过程中，富硅热液与富镁碳酸盐相互作用，形成富镁碳酸盐。随后，富硼流体对橄榄石进行交代作用，诱发不同程度的蛇纹石成矿作用，最终形成坚橄榄石玉石矿床。

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引用次数: 0

The mechanisms of lithium isotope fractionation and their influencing factors: Perspectives from small granitic watersheds across different climatic zones in China 锂同位素分馏机制及其影响因素——来自中国不同气候带花岗岩小流域的视角

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-25 DOI: 10.1016/j.jseaes.2025.106941

Weihua Wu , Hao Yang , Chengxiao Xu , Werner Nel

Lithium isotopes have rapidly emerged as one of the most promising tracers for silicate weathering. To explore the factors influencing lithium isotope fractionation, we investigated small granitic watersheds across various climatic zones in China. Watersheds in the western Sichuan Plateau and cold–temperate Amur River basin exhibit the lowest chemical weathering rates (CWR), while those in tropical Hainan exhibit CWR values approximately ten times higher. Additionally, CWR in the Hainan watersheds is three times greater than those in the tropical Jinghong watersheds with lower runoff. A “boomerang” relationship (parabolic-like, low–high-low) is observed between CWR and dissolved Li isotope ratios (δ⁷Li_diss). Conversely, weathering intensity, expressed as the chemical index of alteration (CIA), shows a corresponding high–low–high trend with δ⁷Li values in the clay fraction of riverbed sediments (δ⁷Li_clay). The trends for CWR vs. δ⁷Li_diss and CIA vs. δ⁷Li_clay differ noticeably. Although watersheds in the western Sichuan Plateau region and Amur River basin share similarly low CWR, their weathering intensity and δ⁷Li_diss values fluctuate, indicating that factors beyond climate climate—such as topography and vegetation— affect physical erosion, weathering intensity, and Li isotope fractionation. At high CWR, δ⁷Li_diss decreases by about 8 ‰ (from +31.6 ‰ to +23.7 ‰), whereas weathering intensity and δ⁷Li_clay remain stable, likely due to dissolution-precipitation and adsorption–desorption processes. Given the complexity of Li isotope behavior during weathering, we conclude that using Li isotopes to trace weathering intensity requires a comprehensive evaluation of climate, topography, water–rock interaction time, and clay mineral composition.

锂同位素已迅速成为最有希望的硅酸盐风化示踪剂之一。为了探讨锂同位素分馏的影响因素，我们对中国不同气候带的小花岗岩流域进行了研究。川西高原和寒温带阿穆尔河流域流域的化学风化速率（CWR）最低，而热带海南流域的CWR值高约10倍。此外，海南流域的CWR是热带景洪流域的3倍，径流较少。在CWR和溶解Li同位素比值（δ7Lidiss）之间观察到一个“回飞器”关系（抛物线状，低-高-低）。相反，风化强度以蚀变化学指数（CIA）表示，与河床沉积物粘土组分（δ7Liclay）的δ7Li值呈相应的高-低-高趋势。CWR相对于δ7Lidiss和CIA相对于δ7Liclay的趋势差异显著。虽然川西高原区和黑龙江流域流域的CWR相似，但其风化强度和δ7Lidiss值存在波动，表明气候以外的因素（如地形和植被）影响了物理侵蚀、风化强度和Li同位素分异。在高CWR时，δ7Lidiss减小了约8‰（从+31.6‰降至+23.7‰），而风化强度和δ7Liclay保持稳定，这可能是溶蚀-沉淀和吸附-解吸过程的结果。考虑到Li同位素在风化过程中的复杂性，我们认为利用Li同位素追踪风化强度需要综合评估气候、地形、水岩相互作用时间和粘土矿物组成。

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引用次数: 0

The rupture process of the September 2022 Guanshan and Chishang Earthquakes: Joint inversion of seismological and geodetic data 2022年9月关山和赤上地震破裂过程：地震和大地测量资料联合反演

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-25 DOI: 10.1016/j.jseaes.2025.106940

Wei-Yu Zhang , Yu-Sheng Sun , Yopi Serhalawan , Po-Fei Chen , Ming-Che Hsieh , Wu-Lung Chang

On 17–18 September 2022, the Mw 6.5 Guanshan and Mw 7.0 Chishang earthquakes, struck the Longitudinal Valley (LV) of Taiwan, the collision boundary between the Eurasian plate and the Philippine Sea plate. Aftershock patterns show that the events occurred within 24 h, only a few kilometers apart, and that both ruptured the west-dipping Central Range Fault (CRF). To investigate their rupture behavior and interaction, we performed a joint inversion of teleseismic, strong-motion, and GNSS data. The resulting finite fault models revealed distinct rupture characteristics, with the Guanshan earthquake mainly rupturing down-dip with minor shallow southward extension, in contrast to the Chishang earthquake, which propagated northward toward the surface and produced two shallow asperities. Combining these models with static Coulomb stress calculations and rupture-velocity analysis indicates that Guanshan may have promoted failure of the Chishang segment through static stress transfer, and that a low-velocity zone and clustered aftershocks between the two hypocenters are consistent with a barrier that limited the northward extent of the Guanshan rupture.

2022年9月17日至18日，关山6.5级地震和奇尚7.0级地震袭击了欧亚板块与菲律宾海板块碰撞边界台湾纵向谷。余震模式表明，这两次地震都发生在24小时内，相距仅几公里，而且都使西倾的中央山脉断层破裂。为了研究它们的破裂行为和相互作用，我们对远震、强震和GNSS数据进行了联合反演。所得有限断层模型显示出明显的断裂特征，关山地震以下倾破裂为主，并有少量浅层向南伸展，而赤上地震则向北向地表传播，并产生两个浅层隆起。将这些模型与静态库仑应力计算和破裂速度分析相结合，表明关山可能通过静态应力传递促进了赤上段的破坏，两个震源之间的低速带和聚集性余震与限制了关山向北破裂范围的屏障相一致。

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引用次数: 0

Constraints of basement geometry and supra-salt cohesion on deformation of salt-bearing fold-and-thrust belts: a discrete-element study 基底几何和盐上黏聚对含盐褶皱冲断带变形的约束：一个离散元研究

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-23 DOI: 10.1016/j.jseaes.2025.106904

Huaibo Zhao , Shuping Chen , Timothy Chris Schmid , Haowei Yuan , Weijia Zhan , Fan Wang

Salt-bearing fold-and-thrust belts (FTBs) in foreland basins exhibit complex structural architectures, primarily governed by the interplay among basement geometry, supra-salt mechanical strength, and the detachment behavior of intervening salt layers. However, the respective roles of basement surface geometry and supra-salt cohesion in controlling deformation localization, thrust segmentation, and fold development remain poorly constrained, particularly in regions with limited subsalt seismic imaging. To address this gap, we conducted two-dimensional discrete element method (DEM) simulations to systematically assess how variations in basement surface geometry and supra-salt cohesion influence the structural evolution of salt-bearing FTBs. The results show that lateral variations in basement morphology produce significant heterogeneity in salt layer thickness, thereby strongly influencing salt particle rearrangement and deformation localization. Redistribution of salt particles from thick to thin zones leads to compression and uplift in the overburden, while reverse movement induces extension and subsidence. A relatively low supra-salt cohesion promotes more rapid deformation front propagation, increased fold density, and more frequent salt piercement, whereas a relatively high cohesion delays deformation front propagation and favors fewer but higher-amplitude folds and enhanced thrust faulting. Comparisons with representative natural examples demonstrate that the models broadly capture the main structural features of salt-related FTBs at a regional scale, including large-scale thrust systems and salt-cored folds. Overall, our findings highlight that basement relief and supra-salt cohesion are first-order controls on structural evolution in compressional salt-bearing systems, thereby enhancing the understanding of deformation localization, thrust segmentation, and fold development.

前陆盆地含盐褶皱冲断带构造结构复杂，主要受基底几何形状、盐层超机械强度和中间盐层脱离行为的相互作用支配。然而，在盐下地震成像有限的地区，基底表面几何形状和盐上黏结在控制变形局部化、逆冲分割和褶皱发育方面的作用仍然知之甚少。为了解决这一空白，我们进行了二维离散元方法（DEM）模拟，系统地评估了基底表面几何形状和超盐黏聚的变化如何影响含盐FTBs的结构演化。结果表明，基底形态的横向变化导致盐层厚度的非均质性显著，从而强烈影响盐颗粒的重排和变形局部化。盐颗粒由厚带向薄带的再分布导致覆盖层的压缩和隆升，而逆移则导致覆盖层的伸展和沉降。较低的超盐黏聚性促进了变形前缘的快速扩展、褶皱密度的增加和盐侵的频繁发生，而较高的超盐黏聚性则延缓了变形前缘的扩展，有利于褶皱的减少和振幅的提高，逆冲断裂的增强。与代表性自然实例的比较表明，该模型在区域尺度上广泛地捕捉了盐相关FTBs的主要结构特征，包括大型逆冲系统和盐芯褶皱。综上所述，基底起伏和盐上黏结是挤压含盐体系构造演化的一级控制因素，从而增强了对变形局部化、逆冲分割和褶皱发育的认识。

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引用次数: 0

Late Archean–early Proterozoic mafic intrusions in the Aravalli Craton (NW India): Implications for the reconstruction of the Kenorland and Columbia supercontinents 印度西北部Aravalli克拉通晚太古宙-早元古代基性侵入：对Kenorland和Columbia超大陆重建的启示

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-23 DOI: 10.1016/j.jseaes.2025.106937

Beiyu Zhou , Bin Huang , Manoj K. Pandit , Wei Wang

Geochronological and geochemical data from mafic intrusions in the Aravalli Craton provide critical insights into the paleogeographic reconstruction of NW India within the Kenorland and Columbia supercontinents. The late Archean Udaipur mafic dykes (2572 ± 12 Ma) display elevated Zr/Nb (12.0–19.2), La/Nb (1.67–3.11) and Ba/Nb (9.62–225) and low Ti/Zr (97.3–100) ratios, indicating derivation from a spinel lherzolite mantle source metasomatized by subduction-related fluids. On the other hand, the Paleoproterozoic Khetri mafic dykes (1848 ± 9 Ma) show comparable Zr/Nb, La/Nb, and Ba/Nb but distinctly higher Th/Nb (1.23–1.32) and Th/Zr (0.11–0.13) ratios, suggesting their derivation from a garnet-spinel lherzolite mantle source metasomatized by both arc-related fluids and melts derived from subducted sediments. The subduction-related geochemical signatures of the ca. 2.57 Ga Udaipur mafic intrusions indicate prolonged arc-related magmatic process characterized by mantle underplating played a vital role in the stabilization of the Aravalli Craton during the late Archean. In contrast, the transitional geochemical characteristics of the ca. 1.85 Ga Khetri mafic rocks mark a tectonic transition from subduction-related to extensional regimes during the Columbia supercontinent assembly. Temporal and geochemical correlations between these mafic magmatic events and coeval ones in the South Indian, Western Australian, and North China cratons support the models suggesting a close spatial proximity of these cratonic blocks during both the late Archean Kenorland (ca. 2.7–2.5 Ga) and the Paleoproterozoic Columbia supercontinent amalgamation processes (ca. 2.0–1.8 Ga).

来自Aravalli克拉通的基性侵入岩的年代学和地球化学数据为在Kenorland和Columbia超大陆内重建西北印度的古地理提供了重要的见解。太古宙晚期乌代浦尔基性岩脉（2572±12 Ma）表现出较高的Zr/Nb（12.0 ~ 19.2）、La/Nb（1.67 ~ 3.11）和Ba/Nb（9.62 ~ 225）比值和较低的Ti/Zr（97.3 ~ 100）比值，表明其来源为俯冲流体交代的尖晶石—辉橄榄岩地幔源。另一方面，古元古代khetrii基性岩脉（1848±9 Ma）的Zr/Nb、La/Nb和Ba/Nb比值相当，但Th/Nb比值（1.23 ~ 1.32）和Th/Zr比值（0.11 ~ 0.13）明显较高，表明其来源为石榴石-尖晶石-辉橄榄岩地幔源，由弧相关流体和俯冲沉积物的熔体交代。约2.57 Ga乌代浦尔基性侵入岩的俯冲相关地球化学特征表明，以幔底构造为特征的长时间弧相关岩浆作用在太古代晚期Aravalli克拉通的稳定中发挥了重要作用。相比之下，约1.85 Ga Khetri基性岩石的过渡地球化学特征标志着哥伦比亚超大陆组合时期从俯冲向伸展的构造过渡。这些岩浆事件与同期南印度、西澳大利亚和华北克拉通的岩浆事件的时间和地球化学对比支持了这些克拉通地块在晚太古代Kenorland（约2.7-2.5 Ga）和古元古代哥伦比亚超大陆合并过程（约2.0-1.8 Ga）中空间接近的模型。

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引用次数: 0

Middle segment of the Red River fault: Numerical simulation of slip rates with implications for the absence of major historical earthquakes 红河断层中段：滑动率的数值模拟及其对历史上没有大地震的影响

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-22 DOI: 10.1016/j.jseaes.2025.106933

Jianling Cao , Yaolin Shi , Hui Wang , Xiaoxia Liu

The middle segment of the Red River fault (RRF) in southwestern China has historically lacked large earthquakes, unlike its parallel northern fault zone. To explain the reason for the absence of historical seismicity on the middle RRF, we developed a 3D viscoelastic–plastic model simulating slip partitioning between these structures, using GNSS and short-baseline geodetic constraints. The simulated horizontal velocities match observations well. Based on data fitting, the optimal mechanical parameters are determined as follows: a fault viscosity of 10¹⁹ Pa·s, and plastic yield strengths of 10 MPa and 20 MPa for the straight and Big Bend sections of the middle segment of the RRF, respectively; the corresponding dextral slip rates are: 1.5 mm/a for the straight RRF section, 1.0–1.5 mm/a for its Big Bend section, 1.0–1.5 mm/a for the Chuxiong fault, 2.5–3.0 mm/a for the Qujiang fault, and 0.5 mm/a for the Shiping fault. Slip rates are more sensitive to plastic yield strength than viscosity, as simulations exceed viscoelastic relaxation time. Estimated recurrence intervals with slip rates we obtain for M 7–8 earthquakes on the middle segment of the RRF range from 1200 to 3500 years. This long recurrence interval—compared to local earthquake written history about four to five centuries in the region—may explain the absence of large historical earthquakes on the middle segment of the RRF. Another possible reason is that the middle RRF may currently be in a seismically quiescent period if its parallel strike-slip faults alternate in activity.

与与之平行的华北断裂带不同，中国西南红河断裂带中段历史上缺乏大地震。为了解释中部RRF缺乏历史地震活动的原因，我们开发了一个三维粘弹塑性模型，使用GNSS和短基线大地测量约束来模拟这些结构之间的滑动划分。模拟的水平速度与观测结果吻合较好。通过数据拟合，确定了RRF中段直段和大弯段的最佳力学参数：断层黏度为1019 Pa·s，塑性屈服强度分别为10 MPa和20 MPa；对应的右向滑动速率为：RRF直段1.5 mm/a，大弯段1.0 ~ 1.5 mm/a，楚雄断裂1.0 ~ 1.5 mm/a，曲江断裂2.5 ~ 3.0 mm/a，石坪断裂0.5 mm/a。滑移率对塑性屈服强度比粘度更敏感，因为模拟超过粘弹性松弛时间。我们在RRF中段得到的7-8级地震的估计再发间隔为1200 - 3500年。与该地区大约4到5个世纪的当地地震记录相比，这种较长的重复周期可能解释了RRF中段历史上没有大地震的原因。另一个可能的原因是，如果其平行走滑断层活动交替，则中部RRF目前可能处于地震静息期。

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引用次数: 0

Late Silurian arc-continent collision and Permian-Triassic closure of Paleo-Asian Ocean in southeastern Central Asian Orogenic Belt: insight from the multiphase deformation from the eastern Bainaimiao arc belt, China 中亚造山带东南部晚志留世弧陆碰撞与古亚洲洋二叠纪-三叠纪闭合：来自白耐庙弧带东部多期变形的启示

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-22 DOI: 10.1016/j.jseaes.2025.106918

Falak Sheir , Jiafu Chen , Yichang Liu , Xu Ma , Wei Li , Yuqi Liu , Yi Zhang , Zhenghe Zhao

The collision between the Bainaimiao arc belt and the North China Craton, and the subsequent closure of the Paleo-Asian Ocean, are two major tectonic events for the Central Asian Orogenic Belt. However, the timing of these events remains controversial because the deformation fabrics that record crucial information about the collision history are poorly constrained. To address this, we conducted detailed structural analysis, quartz c-axis fabric analysis, and zircon U-Pb geochronology of the ductile deformation fabrics within the Chenjiatun shear zone, located east of the Bainaimiao arc belt. The structural analysis indicates that the deformation zone records two main ductile deformation events, D1 and D2, defined by S1 and S2 foliations. The S1 foliations (D1) trend ESE, plunge SE, and the S2 foliations (D2) trend ENE & NE, plunge NW & SE, respectively. Each deformation event is further subdivided into early-late sub-stages based on differences in fabric orientation and deformation characteristics. The D1a and D2 display dextral strike-slip shearing, while D1b involves sinistral strike-slip shearing. Microstructures and quartz c-axis patterns indicate that D1 occurred at high-temperature conditions (∼600–700 °C) under amphibolite facies conditions and D2 at medium temperature (∼400–500 °C) under upper green-schist facies conditions. The zircon U–Pb dating reveals that the deformation occurred at 423 Ma for D1b, 264–261 Ma for D2a, and 260–243 Ma for D2b. These results, combined with previous data, conclude that the D1 event records the Late Silurian Bainaimiao arc belt-North China Craton collision, while the D2 event represents the initial- to -final closure of the Paleo-Asian Ocean, which occurred from the Middle Permian to the Middle Triassic, followed by an intra-continental collision to the east of the Bainaimiao arc belt within the southeastern Central Asian Orogenic Belt.

百乃庙弧带与华北克拉通的碰撞和随后的古亚洲洋的闭合是中亚造山带的两大构造事件。然而，这些事件发生的时间仍然存在争议，因为记录碰撞历史关键信息的变形结构没有得到很好的约束。为此，我们对百耐庙弧带以东陈家屯剪切带韧性变形构造进行了详细的构造分析、石英c轴组构分析和锆石U-Pb年代学研究。构造分析表明，变形带记录了两个主要的韧性变形事件D1和D2，由S1和S2片理定义。S1片理（D1）倾向于东南偏东，陡降东南；S2片理（D2）倾向于东北偏东，陡降西北偏东。根据织物取向和变形特征的不同，将每个变形事件进一步细分为早期-晚期的子阶段。D1a和D2为右旋走滑剪切，D1b为左旋走滑剪切。显微结构和石英C轴图表明，D1发生在角闪岩相条件下的高温条件下（~ 600 ~ 700℃），D2发生在绿片岩相条件下的中温条件下（~ 400 ~ 500℃）。锆石U-Pb测年结果表明，D1b的变形时间为423 Ma， D2a为264 ~ 261 Ma， D2b为260 ~ 243 Ma。结合前人资料，D1事件记录了晚志留世百乃庙弧带与华北克拉通的碰撞，D2事件代表了中二叠世至中三叠世古亚洲洋的初始至最终闭合，随后在中亚造山带东南部的百乃庙弧带以东发生了大陆内碰撞。

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引用次数: 0

Miocene high-pressure metamorphism of garnet-bearing amphibolites in the Cona area, southern Tibet: Insights into the tectonic evolution of the Higher Himalaya 藏南柯纳地区中新世含石榴石角闪岩高压变质作用：对高喜马拉雅构造演化的启示

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-22 DOI: 10.1016/j.jseaes.2025.106935

Khizar Hayat , Laixi Tong , Zhao Liu , Christopher J.L. Wilson , Xiaohan Liu , Kexin Wu , Xinyue Han

The metamorphic evolution of the Higher Himalayan rocks in southern Tibet has been characterized through detailed studies of metapelites, whereas the associated amphibolites remain largely unexplored. In this paper, we describe detailed petrography, mineral chemistry, phase-equilibrium modeling, and zircon U-Pb ages of garnet-bearing amphibolites in the Cona area, southern Tibet. The rocks record three distinct metamorphic stages M1, M2, and M3. Prograde stage (M1) is defined by a mineral assemblage of garnet with amphibole, biotite, and plagioclase, crystallized under pressure–temperature (P-T) conditions of 9.5 kbar and 720 °C. Peak metamorphic stage (M2) is characterized by the existence of garnet, amphibole, biotite, plagioclase, quartz, ilmenite, and rutile, with P-T conditions of 12 kbar and 810 °C. Retrograde stage (M3) comprising garnet, K-feldspar, plagioclase, and quartz, stable at 8.5 kbar and 710 °C. U-Pb ages of zircon indicate that these amphibolites experienced anatectic metamorphism between 28 and 15 Ma. There is an increase in the metamorphic thermobaric ratios from 675–835 °C/GPa to 875 °C/GPa, rising the geothermal gradients from 18.2 °C/km to 24.8 °C/km. Integrating our results with previous studies, it is concluded that the Cona amphibolites underwent peak HP metamorphism, followed by a decompressional path similar to that of Cona metapelites during the Miocene, reflecting a phase of post-collisional rapid exhumation.

通过对变质岩的详细研究，对藏南高喜马拉雅岩石的变质演化进行了描述，而与之相关的角闪岩则大多未被发现。本文详细描述了藏南柯纳地区含石榴石角闪岩的岩石学、矿物化学、相平衡模拟和锆石U-Pb年龄。岩石记录了三个不同的变质阶段M1， M2和M3。发展阶段（M1）是由石榴石、角闪孔、黑云母和斜长石组成的矿物组合，在9.5 kbar和720℃的压力-温度（P-T）条件下结晶。峰变质期（M2）以石榴石、角闪孔、黑云母、斜长石、石英、钛铁矿和金红石为主，P-T条件为12 kbar，温度为810℃。逆行期（M3）由石榴石、钾长石、斜长石和石英组成，稳定在8.5 kbar和710°C。锆石U-Pb年龄表明，这些角闪岩在28 ~ 15 Ma之间经历了深熔变质作用。变质热压比由675 ~ 835℃/GPa增加到875℃/GPa，地温梯度由18.2℃/km增加到24.8℃/km。综合前人的研究结果，我们认为Cona角闪岩经历了HP变质的高峰，随后的减压路径与Cona角闪岩在中新世类似，反映了碰撞后的快速挖掘阶段。

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引用次数: 0