Journal of Asian Earth Sciences最新文献

Wolframite and cassiterite geochemistry deciphers W–Sn ore formation: A case study from the Zuoba quartz-vein tungsten deposit, South China 黑钨矿和锡石地球化学对钨锡矿形成的解释——以华南左坝石英脉钨矿为例

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-08 DOI: 10.1016/j.jseaes.2026.106953

Kai-Han Zhang , Jun-Yi Pan , Pei Ni , Gen-Wen He , Lin-Lin Peng , Ming-Sen Fan , Yuan-Long Zhang , Wen-Sheng Li

The Zuoba deposit is a typical quartz-vein type tungsten deposit in the Nanling metallogenic belt. Here, we present LA-ICP-MS U–Pb dating and trace-element analyses of wolframite and cassiterite to decipher the ore forming process of this deposit. Wolframite yields a lower intercept age of 156.7 ± 0.9 Ma, and cassiterite shows a weighted mean ²⁰⁶Pb/²³⁸U age of 155.2 ± 1.5 Ma. Wolframite shows enrichments in Nb, Ta, and Sc, along with a distinctly low Zr/Hf ratio and left-inclined REE patterns marked by negative Eu anomalies. This geochemical signature points to ore-forming fluids derived predominantly from highly evolved granites and precipitated under reducing conditions. Coupled Mg–Fe variations suggest alteration-driven Fe input, highlighting the contribution of wall-rock interaction to wolframite precipitation. Cassiterite exhibits CL-bright and CL-dark sector zoning, with continuous growth bands across both, indicating that these zones developed synchronously during the same crystallization stage. Variations in W and U between the sectors are primarily attributed to crystal growth kinetics rather than to changes in fluid redox conditions. Cassiterite Zr/Hf ratios exhibit a strong sensitivity to the degree of evolution and chemical composition of the parental magmas, with W-dominated systems typically characterized by lower values than those from Sn-dominated deposits. Because Nb, Ta, and Nb/Ta show pronounced sector-zoning differences, only CL-bright sector data should be used to interpret the ore genesis. The Nb and Ta variations of Zuoba cassiterite reflect temperature fluctuations during cassiterite deposition and suggest a possible contribution from meteoric-water mixing during cassiterite mineralization.

左坝矿床是南岭成矿带典型的石英脉型钨矿床。本文对黑钨矿和锡铁矿进行LA-ICP-MS U-Pb定年和微量元素分析，以揭示该矿床的成矿过程。黑钨矿的截距年龄为156.7±0.9 Ma，锡石的加权平均206Pb/238U年龄为155.2±1.5 Ma。黑钨矿富集Nb、Ta和Sc， Zr/Hf比值低，稀土元素左倾，Eu呈负异常。这一地球化学特征表明成矿流体主要来自高度演化的花岗岩，并在还原条件下沉淀。Mg-Fe耦合变化表明蚀变驱动的Fe输入，突出了围岩相互作用对黑钨矿降水的贡献。锡石呈现出cl -亮区和cl -暗区分带，两者之间有连续的生长带，表明这两个区域在同一结晶阶段是同步发育的。W和U在扇区之间的变化主要归因于晶体生长动力学，而不是流体氧化还原条件的变化。锡石的Zr/Hf比值对母岩岩浆的演化程度和化学成分具有很强的敏感性，其中以w为主的锡石系统的Zr/Hf比值通常低于以sn为主的锡石系统。由于Nb、Ta和Nb/Ta显示出明显的分区差异，因此只能使用cl -亮区数据来解释矿石成因。左坝锡石的Nb和Ta变化反映了锡石沉积过程中的温度波动，表明锡石成矿过程中可能有大气-水混合作用。

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引用次数: 0

Multiscale pore structure and coalbed methane in the Jurassic deep coal seams of Southern Junggar Basin, China 准噶尔盆地南部侏罗系深部煤层多尺度孔隙结构与煤层气

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-06 DOI: 10.1016/j.jseaes.2026.106955

Zhonghong Chen , Kegong Dong , Weijiang Yao , Xin Hu , Xiaojie Jin , Xu Ou

This study addresses key scientific challenges regarding reservoir space in deep coal reservoirs (>2400 m). The multi-scale pore structure in coal rocks, as well as the occurrence state of CBM governed by this structure, such as the proportional fractions of adsorbed gas and free gas, plays a crucial role in comprehending the permeability and adsorption capacity of deep coal rocks. The pore structure and gas content of Jurassic Xishanyao Formation (J₂x) coal seams (2460–2585 m) in the central southern Junggar Basin were investigated using multiscale experimental techniques, including FE-SEM, micro-computed tomography (μ-CT), high-pressure mercury intrusion porosimetry (MIP), low-temperature N₂/CO₂ physisorption, nuclear magnetic resonance (NMR), and isothermal adsorption experiments. Results indicate that the full-scale pore structure is dominated by macropores (>50 nm, avg. 67.7 % of pore volume), followed by micropores (<2 nm, avg. 27.9 %). Critically, micropores contribute 96.43 % of the specific surface area, serving as the primary reservoir for adsorbed gas. Confining pressure (3.45–35 MPa) significantly degrades reservoir quality, causing 23.2 %–63.5 % porosity loss and 97.5 %–99.4 % permeability decline. Deep coals host both adsorbed and free gas. Adsorbed gas content (4.63–10.09 cm³/g) is controlled by micropore volume and specific surface area, while free gas content (6.16–8.04 cm³/g) correlates positively with macropore volume and constitutes a proportion of 44.8 % in average, significantly exceeding levels in shallow CBM reservoirs. Effective porosity (avg. 2.06 %) provided by macropores (including micro-fractures) forms the storage space for free gas. The results provide a crucial theoretical foundation for evaluating deep CBM reservoirs.

该研究解决了深层煤储层（>2400 m）储层空间的关键科学挑战。煤岩的多尺度孔隙结构以及受此结构支配的煤层气赋存状态，如吸附气和游离气的比例分数，对理解深部煤岩的渗透率和吸附能力起着至关重要的作用。采用FE-SEM、微计算机断层扫描（μ-CT）、高压压汞法（MIP）、低温N2/CO2物理吸附、核磁共振（NMR）和等温吸附等多尺度实验技术，对准噶尔盆地中南部侏罗系西山窑组（J2x）煤层（2460 ~ 2585 m）孔隙结构和含气量进行了研究。结果表明，全尺度孔隙结构以大孔（50 nm，平均占孔隙体积的67.7%）为主，其次为微孔（2 nm，平均占孔隙体积的27.9%）。微孔占比表面积的96.43%，是吸附气的主要储集层。围压（3.45 ~ 35 MPa）显著降低储层质量，导致孔隙度损失23.2% ~ 63.5%，渗透率下降97.5% ~ 99.4%。深部煤既有吸附气又有游离气。吸附气含量（4.63 ~ 10.09 cm3/g）受微孔体积和比表面积的控制，而游离气含量（6.16 ~ 8.04 cm3/g）与大孔体积呈正相关，平均占44.8%，显著高于浅层煤层气储层。大孔隙（包括微裂缝）提供的有效孔隙度（平均为2.06%）形成了游离气体的储存空间。研究结果为深部煤层气储层评价提供了重要的理论依据。

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引用次数: 0

Factors controlling the formation of high-Cr podiform chromite deposits 高铬足状铬铁矿床形成的控制因素

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-06 DOI: 10.1016/j.jseaes.2026.106958

Haitao Ma, Jingsui Yang, Pengjie Cai

Understanding the genesis of podiform chromite deposits in ophiolitic mantle provides important insights into the evolution of oceanic lithospheric mantle. The melt-rock interaction between boninitic melt and mantle harzburgites is widely used to explain the genesis of high-Cr podiform chromite deposits. Nevertheless, more quantitative work is still lacking. In this study, we carried out detailed petrological and mineralogical work on the chromitite ores and host rocks from the Luobusa ophiolite, and carried out systematic thermodynamic modelling work to evaluate the factors that may affect the formation of high-Cr podiform chromite deposits. The chromitite ores consist of massive chromitites and disseminated chromitites, whose chromites exhibit high Cr values of 78.1–79.1 and 77.3–78.9, respectively. The host rocks include dunite envelopes and harzburgites, whose chromites show Cr values of 64.2–77.1 and 42.5–53.1, respectively. The parental magma of chromitite ores, calculated by chromite major and trace element data, shows a strong affinity with boninitic melts. Thermodynamic modelling results declare that the refractory degree of harzburgite is the primary factor controlling the enrichment of Cr elements in chromites. Additionally, a low melt-rock ratio, low pressure, and moderate water content in boninitic melt all promote the enrichment of Cr content in chromite. The chromitite ores and dunites from the Luobusa crust-mantle transition zone in this study are generated from the interaction process of the hydrous (water contents = 3–5 wt%) low-Ca boninitic melt and refractory harzburgites under the condition of low melt-rock ratios (1:100 to 1:20) and lower pressure (1.0 GPa).

了解蛇绿质地幔中足状铬铁矿矿床的成因，对研究海洋岩石圈地幔演化具有重要意义。硼质熔体与地幔碳酸盐之间的熔体-岩石相互作用被广泛用于解释高铬脚状铬铁矿矿床的成因。然而，还缺乏更多的量化工作。本研究对罗布萨蛇绿岩中铬铁矿矿石和寄主岩进行了详细的岩石学和矿物学研究，并开展了系统的热力学模拟工作，评价了影响高铬脚状铬铁矿矿床形成的因素。铬铁矿矿石由块状铬铁矿和浸染状铬铁矿组成，其中铬铁矿Cr值较高，分别为78.1 ~ 79.1和77.3 ~ 78.9。赋矿岩石为泥质包壳岩和黑刺岩，其铬铁矿的Cr值分别为64.2 ~ 77.1和42.5 ~ 53.1。铬铁矿主、微量元素数据表明，铬铁矿母岩浆与硼质熔体有较强的亲和关系。热力学模拟结果表明，锰矿难熔程度是铬铁矿中Cr元素富集的主要控制因素。低熔岩比、低压力和中等含水量均有利于铬铁矿中Cr含量的富集。本文研究的罗布沙壳幔过渡带中铬铁矿和泥质岩是在低熔岩比（1:100 ~ 1:20）和低压（1.0 GPa）条件下，含水（含水量= 3 ~ 5 wt%）低钙硼质熔体与难熔碳酸盐相互作用的产物。

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引用次数: 0

Dynamic rupture modeling of the Kachchh Mainland Fault (KMF), Bhuj, India: Implications for earthquake risk assessment 印度Kachchh大陆断层（KMF）的动态破裂模拟：地震风险评估的意义

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-06 DOI: 10.1016/j.jseaes.2026.106956

T.C. Sunilkumar , Danhua Xin , Zhenguo Zhang , V.K. Gahalaut , Zijia Wang , Zhongqiu He

The seismic hazard associated with the Kachchh Mainland Fault, the prominent fault of the Kachchh failed rift region of western India, remains high, where the 2001 Mw∼7.7 Bhuj earthquake occurred. This area necessitates an in-depth investigation into the fault’s dynamics and associated risks. We employed advanced physics-based (PB) simulations to explore dynamic rupture scenarios, focusing on how rupture influences ground motion patterns and hazard. We adopted a magnitude of Mw 7.7 consistent with the 2001 event, with the fault segment immediately west of the 2001 epicenter, considering its possible dimensions. By varying nucleation points across models, we observed comparable rupture characteristics; however, ground motion simulations produced distinctly different patterns, influenced by directivity, hanging-wall effects, and fault geometry. This highlights the advantages of using PB simulations over traditional Ground Motion Prediction Equations and other models. Simulated intensity levels in models peak at Modified Mercalli Intensity (MMI) IX, with site amplification leading to intensities up to X. We evaluated population exposure to different MMI levels, revealing distinct patterns that correlate with variations in ground motion. These findings underscore the critical need for comprehensive seismic risk assessments that integrate a detailed study of the earthquake source. Although the KMF has not historically been linked to catastrophic earthquakes in recent centuries, our results indicate its potential for significant large events, necessitating enhanced earthquake monitoring and preparedness, and assessment of neighboring fault systems.

与Kachchh大陆断层有关的地震危险性仍然很高，Kachchh大陆断层是印度西部Kachchh失败裂谷区的主要断层，2001年发生了Mw ~ 7.7的Bhuj地震。该地区需要对断层的动态和相关风险进行深入调查。我们采用先进的基于物理的（PB）模拟来探索动态破裂场景，重点研究破裂如何影响地面运动模式和危害。考虑到其可能的规模，我们采用的震级为7.7兆瓦，与2001年的事件一致，断层段位于2001年震中的西面。通过不同模型的成核点，我们观察到类似的破裂特征；然而，受指向性、上盘效应和断层几何形状的影响，地面运动模拟产生了明显不同的模式。这突出了使用PB模拟比传统的地震动预测方程和其他模型的优势。模型模拟的强度水平在修正Mercalli强度（MMI） IX处达到峰值，位点扩增导致强度达到x。我们评估了不同MMI水平下的种群暴露，揭示了与地面运动变化相关的不同模式。这些发现强调了全面的地震风险评估的迫切需要，其中包括对震源的详细研究。虽然近几个世纪以来，KMF在历史上与灾难性地震没有联系，但我们的研究结果表明，它有可能发生重大的大事件，有必要加强地震监测和准备，以及对邻近断层系统的评估。

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引用次数: 0

Source and accumulation of helium in the Dongsheng gas Field, Ordos Basin, China: Insights from noble gas isotopes 鄂尔多斯盆地东胜气田氦源与聚集：稀有气同位素的启示

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-06 DOI: 10.1016/j.jseaes.2026.106959

Yu Gao , Shuangjian Li , Xiaoqi Wu , Dongya Zhu , Pengpeng Li , Linlin Wang , Guangxiang Liu , Jiahao Lv , Jiarun Liu , Quanyou Liu

Helium, vital for advanced technologies, is generated in the crust via uranium (U) and thorium (Th) decay. The crystalline basement is a proven source of helium. In contrast, the role of sedimentary rocks, while often considered significant, has lacked definitive proof. This study provides the isotopic evidence to deconvolve these two crustal sources and verify the significant role of sediment. Our analysis of the Dongsheng Gas Field, Ordos Basin, China, reveals that air-derived noble gases reflect open-system water–gas equilibration, a process occurring within the reservoir. Whereas crust-derived noble gases likely pre-aggregated and migrated together with hydrocarbons, thereby preserving a clear signature of their original sources. Within this preserved signature, a depletion of ²¹Ne* (where * denotes a crustal origin) is observed. This depletion produces an unusual negative correlation between ²¹Ne*/³⁶Ar and ⁴⁰Ar*/³⁶Ar, in contrast to the expected positive trend. This pattern is interpreted as the mixing of a fluid from coal-bearing strata (⁴⁰Ar*/³⁶Ar = 130 ± 10) with a ²¹Ne*-depleted fluid from the basement (⁴⁰Ar*/³⁶Ar = 2250 ± 150). Modeling suggests that only ∼ 0.26 % of basement-generated ²¹Ne* is retained. We propose a helium accumulation model in which initial preservation was inefficient owing to the absence of a seal, whereas the main accumulation was driven by hydrocarbon charging, which acted as a carrier fluid stripping helium from coal-bearing strata. These results demonstrate that U- and Th-rich sedimentary rocks can serve as a potential helium source in natural gas, which refines exploration strategies for helium in cratonic basins.

氦对先进技术至关重要，它是通过铀(U)和钍（Th）的衰变在地壳中产生的。晶体基底是氦的一个已被证实的来源。相比之下，沉积岩的作用，虽然经常被认为是重要的，但缺乏明确的证据。本研究为这两个地壳源的反褶积提供了同位素证据，并验证了沉积物的重要作用。对鄂尔多斯盆地东胜气田的分析表明，气源惰性气体反映了开放系统的水气平衡，这是一个发生在储层内部的过程。而源自地壳的惰性气体可能与碳氢化合物一起预先聚集和运移，从而保留了其原始来源的清晰特征。在这个保存下来的特征中，观察到21Ne*的损耗（其中*表示地壳起源）。这种消耗在21Ne*/36Ar和40Ar*/36Ar之间产生了不寻常的负相关，与预期的正趋势相反。该模式被解释为含煤地层流体（40Ar*/36Ar = 130±10）与基底流体（40Ar*/36Ar = 2250±150）的混合。模拟表明，只有~ 0.26%的地下室产生的21Ne*被保留。本文提出了一种氦成藏模式：由于缺乏封闭，初始保存效率不高，而主要的成藏是由油气充注驱动的，油气充注作为载体流体从含煤地层中剥离氦。这些结果表明，富铀、富钍沉积岩可作为天然气中潜在的氦源，为克拉通盆地氦勘探提供了新的思路。

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引用次数: 0

Precise subsurface structural delineation of gold fields and crustal architecture from remote sensing and satellite geophysical data in Asir and Jiddah terranes, Makkah area, Saudi Arabian Shield 基于遥感和卫星地球物理数据的沙特阿拉伯地盾麦加地区Asir和Jiddah地块金矿地下构造和地壳结构精确圈定

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-06 DOI: 10.1016/j.jseaes.2026.106957

Ahmed M. Eldosouky , Reda A.Y. El-Qassas , Mohamed A. Abd El‑Wahed , Abdullah Othman , Luan Thanh Pham , Mohamed Attia

The crustal structure and gold fields of the Asir and Jiddah terranes in the Makkah region of the Arabian Shield are examined using a comprehensive methodology that integrates Landsat-8 imagery with gravity and magnetic data. An Enhanced Horizontal Gradient Amplitude (EHGA) filter helps identify the structures controlling the gold mineralization. The region is primarily characterized by the Ad Damm and Fatima fault zones, which are mylonitic dextral shear zones exhibiting flexural slip folding and a thrust duplex system. Various structural orientations distinguish the Asir and Jiddah terranes, including NW, NE, N-S to NNE, E-W, and WNW trends. Deeper structural features generally follow the same trends, with some shifts toward N-S and NE-to-ENE directions. The study covers gold fields such as As Suq, Ar Rjum, Ad Duwayhi, and Shaab Al Taare, where mineralization is influenced by E-W and N-S trending structures. The crust thickness (Moho interface) in the Makkah area varies from 25 to 46 km. The region has undergone three major deformation phases, with the youngest event being the most intense, producing folds, faults, and fractures. These results offer new insights into the tectonic architecture and structural framework of the Arabian Shield in this area and enhance the understanding of the geodynamic processes and crustal formation shaping Asir and Jiddah terranes.

阿拉伯地盾麦加地区的阿西尔和吉达地体的地壳结构和金矿利用综合方法进行了检查，该方法将Landsat-8图像与重力和磁数据结合起来。增强水平梯度振幅（EHGA）滤波有助于识别控制金矿化的构造。该区主要以阿达姆断裂带和法蒂玛断裂带为特征，为糜棱质右旋剪切带，表现为弯曲滑动褶皱和逆冲复式体系。不同的构造取向区分了阿西尔和吉达地块，包括NW、NE、N-S - NNE、E-W和WNW走向。深层构造特征总体上遵循相同的趋势，但有向北-南、北东-东东方向转移的趋势。研究范围包括as Suq、Ar Rjum、Ad Duwayhi、Shaab Al Taare等金矿，成矿作用受东西向和北南向构造影响。麦加地区地壳厚度（莫霍界面）在25 ~ 46 km之间。该地区经历了三个主要的变形阶段，其中最年轻的事件是最强烈的，产生褶皱、断层和裂缝。这些结果为认识该地区阿拉伯地盾的构造结构和构造格架提供了新的见解，并增强了对形成阿西尔和吉达地体的地球动力学过程和地壳形成的认识。

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引用次数: 0

Diverse metamorphic P‒T‒t paths of the Mogutai tectono-metamorphic mélange, eastern Paleozoic Dunhuang Orogenic Belt, northwestern China 东古生代敦煌造山带木谷台构造-变质带P-T-t变质路径的多样性

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-06 DOI: 10.1016/j.jseaes.2026.106967

Yan-Lin Zhao , Yichao Chen , Xue-Li Jia , Hui C.G. Zhang , Zhen M.G. Li , Longxiang Quek , Chun-Ming Wu

The Mogutai block, located in the eastern segment of the Paleozoic Dunhuang Orogenic Belt, northwestern China, represents a typical tectono-metamorphic mélange. It exhibits the characteristic block-in-matrix structure, with the matrix being metasedimentary rocks and the tectonic blocks consisting of amphibolite and mafic granulite. Seven representative metamorphic rocks were collected in a limited area with ∼ 1.3 km long and ∼ 1.2 km wide. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating of metamorphic zircon of these rocks reveals that the metamorphic events occurred at ∼ 462‒350 Ma. Different mineral assemblages of the metamorphic rocks were formed sequentially in the three distinct metamorphic stages, i.e., the prograde metamorphism (M1), the peak metamorphism (M2), and the retrograde metamorphism (M3). Diverse clockwise metamorphic pressure − temperature (P − T) paths were reconstructed by geothermobarometry, including the P − T paths of the mafic granulite passing from 4.6 − 6.1 kbar/630 − 650 °C (M1) through 11.9 − 16.3 kbar/710 − 830 °C (M2) and finally to 7.8 − 8.7 kbar/720 − 770 °C (M3), as well as from 6.7 kbar/720 °C (M1) through 8.0 kbar/750 °C (M2) and finally to 4.6 kbar/700 °C (M3) for the garnet amphibolite, respectively. Different peak metamorphic P − T conditions of the metapelitic lenses were estimated to be between 3.7 − 11.9 kbar and 610 − 780 °C. The significant differences in peak P − T conditions of these metamorphic rocks suggest that they were subducted to varying depths during the subduction process, and finally were amalgamated during exhumation, resulting in formation of the Mogutai tectono-metamorphic mélange.

木谷台地块位于中国西北古生代敦煌造山带东段，是一个典型的构造变质带。以变质沉积岩为基质，以角闪岩和基性麻粒岩为构造块体，具有块体-基质块体结构特征。在长~ 1.3 km、宽~ 1.2 km的有限区域内，收集到了7块具有代表性的变质岩。激光烧蚀电感耦合等离子体质谱（LA-ICP-MS）对这些岩石的变质锆石进行U-Pb测年，结果表明变质事件发生在~ 462 ~ 350 Ma。变质岩的不同矿物组合依次形成于3个不同的变质期，即进变质期（M1）、峰变质期（M2）和逆变质期（M3）。顺时针方向不同变质压力−温度(P T−)路径被geothermobarometry重建,包括镁铁质麻粒岩的P−T路径从4.6−6.1千巴/ 630−650°C (M1)通过11.9−16.3千巴/ 710−830°C (M2)最后7.8−8.7千巴/ 720−770°C (M3),以及从6.7千巴/ 720°C (M1)通过8.0千巴/ 750°C (M2)最后4.6千巴/ 700°C (M3)石榴角闪岩,分别。不同变质峰P - T条件在3.7 ~ 11.9 kbar和610 ~ 780°C之间。这些变质岩的峰值P - T条件差异显著，说明它们在俯冲过程中俯冲到不同的深度，最终在发掘过程中被合并，形成了木谷台构造变质带。

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引用次数: 0

Effective application of multidimensional scaling for detrital zircon geochronology in the southern Miryang Subbasin, Gyeongsang Basin, Korea 多维标度在庆尚盆地密阳次盆地南部碎屑锆石年代学中的有效应用

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-05 DOI: 10.1016/j.jseaes.2026.106954

Yong-Un Chae , Taejin Choi , Young Ji Joo , Kyung Soo Kim , Sujin Ha , Hyoun Soo Lim

Zircon U-Pb dating was conducted using laser ablation multi-collector inductively coupled plasma mass spectrometry on samples collected from five Natural Monument fossil sites in the southern Miryang Subbasin of the Gyeongsang Basin, Korea. The resulting depositional ages and ages of fossil occurrence are approximately 117 Ma (Aptian) and 113 Ma (Aptian–Albian boundary) in the Hasandong Formation, 104 Ma (Albian) and 96 Ma (Cenomanian) in the Haman Formation, and 93 Ma (Turonian) in the Jindong Formation. By synthesizing the detrital zircon age distributions from this and previous studies, we identify distinct temporal changes in provenance that are more dynamic in the southern subbasin than in its central and northern regions. However, conventional multidimensional scaling (MDS) approaches, which rely on all concordant zircon ages, often obscure provenance signals in volcanic-arc settings due to the dominance of syndepositional volcanic zircons and widely distributed Paleoproterozoic basement rocks. To address this limitation, we applied a geologically informed filtering protocol that removes near-syndepositional volcanic ages (<145 Ma) and non-diagnostic Paleoproterozoic components (>1600 Ma), which commonly mask provenance-sensitive age populations. This refinement focuses on the 1600–145 Ma interval, enhancing the clarity and geological coherence of the resulting MDS configurations. Applying this approach to the Miryang Subbasin dataset improves the separation of samples and reveals diagnostic age patterns consistent with independent geological evidence. Our findings provide refined depositional age constraints and provenance interpretations for the southern Miryang Subbasin and demonstrate a practical framework for enhancing MDS performance in sedimentary basins influenced by syndepositional volcanism.

采用激光烧蚀多收集器电感耦合等离子体质谱法对韩国庆尚盆地密阳次盆地南部5个天然纪念碑化石遗址的样品进行了锆石U-Pb测年。结果表明，哈东组沉积年龄约为117 Ma（阿普田）和113 Ma（阿普田-阿勒边界线），哈曼组沉积年龄约为104 Ma（阿普田界线）和96 Ma（塞诺曼界线），锦东组沉积年龄约为93 Ma（吐鲁番界线）。综合前人研究的碎屑锆石年龄分布，我们发现南缘次盆地物源的时间变化比中部和北部地区更为动态。然而，由于同沉积火山锆石占主导地位，古元古代基底岩分布广泛，传统的多维标度（MDS）方法依赖于所有和谐锆石，往往模糊了火山弧环境中的物源信号。为了解决这一限制，我们采用了一种地质信息过滤方案，去除近同沉积火山年龄（<145 Ma）和非诊断性古元古代成分（>1600 Ma），这些成分通常掩盖了对物源敏感的年龄群体。这种改进主要集中在1600-145 Ma区间，提高了所得MDS配置的清晰度和地质一致性。将该方法应用于密阳次盆地数据集，提高了样品的分离性，揭示了与独立地质证据一致的诊断年龄模式。研究结果为密阳南部次盆地提供了精细的沉积年龄约束和物源解释，并为同沉积火山作用影响下的沉积盆地提高MDS性能提供了实用框架。

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引用次数: 0

Paleo-Pacific slab break-off revealed by Cretaceous I-type and peralkaline A-type granite associations in the Cathaysia Block, SE China 华夏地块白垩系i型和过碱性a型花岗岩组合揭示的古太平洋板块断裂

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-04 DOI: 10.1016/j.jseaes.2026.106949

Ao Li , Wu-Bin Yang , Ning-Bo Li , Shuo Xue , He-Cai Niu , Qiang Shan

Investigating spatially and temporally associated granites can provide significant constraints on regional crustal reworking and geodynamic evolution. A famous instance is the coexistence of Cretaceous I-type and peralkaline A-type granites along the coastal Cathaysia Block; nevertheless, their origins and genetic connections remain controversial. Here, we employed zircon U-Pb-Hf-O isotopes, alongside whole-rock geochemistry and Nd-Hf isotopes, to examine the Qingtian granite association within the Cathaysia Block. Zircon U-Pb dating yields crystallization ages of 106.0 ± 0.5 Ma for the I-type granite and 95.8 ± 0.8 Ma for the peralkaline A-type granite, indicating an ∼10 Myr gap. The I-type granite has variable zircon ε_Hf(t) values (–15.8 to –4.50) and mantle-like δ¹⁸O (4.76–5.91 ‰), demonstrating a hybrid source comprising Mesozoic juvenile mafic lower continental crust (LCC) and Mesoproterozoic-Paleozoic mafic LCC. In contrast, the peralkaline A-type granite displays zircon ε_Hf(t) values of –7.18 to 2.07 and sub-normal mantle δ¹⁸O (4.27–5.22 ‰), together with relatively depleted Nd-Hf isotopes, elevated whole-rock zircon saturation temperatures, and enriched high-field-strength and heavy-rare-earth elements, suggesting a source generated by mixing refractory granulite residues remaining after the I-type melt extraction with melts/fluids released by high-temperature altered oceanic crust (AOC). Combined with regionally coeval oceanic island-like basalts, such AOC-derived component potentially originated from the melting/dehydration of altered gabbroic lower oceanic crust along fractured surfaces. Accordingly, we propose that paleo-Pacific slab break-off represents the likely mechanism for generating this peralkaline A-type magmatism. A compilation of Cretaceous granitoids from the Cathaysia Block further indicates that this break-off occurred at ∼96 Ma.

研究时空关联花岗岩对区域地壳改造和地球动力学演化具有重要的约束作用。一个著名的例子是沿滨海华夏地块白垩系i型和过碱性A型花岗岩共存；然而，它们的起源和基因联系仍然存在争议。本文采用锆石U-Pb-Hf-O同位素，以及全岩地球化学和Nd-Hf同位素，对华夏地块内的青田花岗岩组合进行了研究。锆石U-Pb测年结果显示，i型花岗岩的结晶年龄为106.0±0.5 Ma，过碱性a型花岗岩的结晶年龄为95.8±0.8 Ma，显示出~ 10 Myr的差距。i型花岗岩的锆石εHf(t)值为-15.8 ~ -4.50，δ18O值为4.76 ~ 5.91‰，为中生代幼基性下陆壳（LCC）与中元古代—古生代基性下陆壳（LCC）混合源。而过碱性a型花岗岩的锆石εHf(t)值为-7.18 ~ 2.07，地幔δ18O值为4.27 ~ 5.22‰，Nd-Hf同位素相对减少，全岩锆石饱和温度升高，高场强和重稀土元素富集，表明其成因是i型熔体萃取后残留的难熔麻粒岩残留物与高温蚀变洋壳（AOC）释放的熔体/流体混合形成的。结合区域同时期的海洋类海岛玄武岩，这种aoc衍生成分可能起源于沿断裂面蚀变辉长岩下洋壳的熔融/脱水。因此，我们认为古太平洋板块断裂可能是这一过碱性a型岩浆活动的形成机制。来自华夏地块的白垩纪花岗岩类汇编进一步表明，这种断裂发生在~ 96 Ma。

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引用次数: 0

Distribution and enrichment characteristics of carbonate-hosted clay-type lithium resources in western Guangxi, South China 桂西碳酸盐岩粘土型锂资源分布及富集特征

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-03 DOI: 10.1016/j.jseaes.2026.106948

Jiarong Li , Yazhou Fu , Jiafei Xiao , Huawen Qi , Jiantang Peng , Jian Zhang

Carbonate-hosted clay-type lithium deposits represent a newly recognized lithium resource in China. This study integrates field observations, mineralogical and geochemical analyses from 267 samples collected across 18 stratigraphic sections of the Upper Permian Heshan Formation in western Guangxi, to investigate the distribution and enrichment of lithium. Results reveal significant spatial heterogeneity, with the Pingguo area exhibiting the highest Li enrichment (averaging 3157 ppm in carbonaceous mudstone), while other regions such as Jingxi, Tianyang, and Dahua display only moderate or localized enrichment. Lithium concentration is strongly lithology-dependent: carbonaceous mudstone contains the highest Li, followed by aluminous mudstone and bauxitic rock, whereas ferruginous mudstone and bauxite are largely barren. Cookeite is the primary Li carrier, showing a strong correlation with whole-rock Li (R² = 0.84). We propose that Li-rich kaolinite precipitated from weathering solutions at the karstic unconformity and recrystallized into cookeite during shallow burial diagenesis. Lithium can also occur in clay minerals via isomorphism or adsorption, and organic matter may contribute to enrichment. Geochemical indices (Rb/K, Ni/Co, Sr/Cu, La/Y) indicate deposition under oxidizing, marine-continental transitional, hot-arid, and weakly acidic conditions, favoring Li adsorption and retention. Immobile element and REE signatures suggest detrital materials were mainly derived from peralkaline-peraluminous felsic rocks of the Permian Emeishan large igneous province and a coeval magmatic arc. This work advances the understanding of non-conventional lithium resources in South China and positions western Guangxi as a strategic Li supply base for China’s low-carbon economy.

碳酸盐岩粘土型锂矿床是中国新近认识的锂资源。本研究对广西西部上二叠统鹤山组18个地层剖面的267个样品进行了野外观测、矿物学和地球化学分析，探讨了锂的分布和富集情况。结果显示出明显的空间异质性，平果地区碳质泥岩中Li富集程度最高（平均为3157 ppm），而其他地区如靖西、天阳和大化仅表现出中等或局部富集。锂浓度具有强烈的岩性依赖性：碳质泥岩的锂含量最高，其次是铝质泥岩和铝土矿岩，而铁质泥岩和铝土矿基本上是贫瘠的。Cookeite是Li的主要载体，与全岩Li具有较强的相关性（R2 = 0.84）。我们认为富锂高岭石是在岩溶不整合期从风化溶液中析出，并在浅埋成岩过程中再结晶成库克石。锂也可以通过同形或吸附存在于粘土矿物中，有机质可能有助于富集。地球化学指标（Rb/K、Ni/Co、Sr/Cu、La/Y）表明沉积条件为氧化、海陆过渡、热干旱和弱酸性，有利于Li的吸附和保留。固定元素和稀土元素特征表明，碎屑物质主要来源于二叠系峨眉山大火成岩省和同时期岩浆弧的过碱性-过铝质长英质岩。这项工作促进了对中国南方非常规锂资源的认识，并将广西西部定位为中国低碳经济的战略锂供应基地。

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引用次数: 0