Journal of Asian Earth Sciences最新文献_第3页

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

Impacts of climate and tectonics on orbital-scale sedimentary cycles in the Bohai Bay Basin since the late Pliocene 渤海湾盆地晚上新世以来气候和构造对轨道尺度沉积旋回的影响

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.2026.106952

Yao Wang , Qinmian Xu , Wenchao Niu , Huayu Lu , Hengzhi Lyu , Enlou Zhang , Xianyan Wang

The ambiguous high-frequency precession cycles preserved in sediments, which are ascribed to tectonic and post-depositional disturbances, have prevented a comprehensive understanding of the direct response of the surface system to regional climate changes. To address this gap, this study investigates a well-preserved fluvial-lacustrine sequence drilled from the western region of the subsiding Bohai Bay Basin. Through high-resolution paleomagnetic dating and wavelet analysis of gamma ray data, we evaluate the impacts of regional subsidence and monsoon climate change on sedimentary cyclicities. The results reveal significant sedimentary cyclicities that respond to precession (∼21 kyr), obliquity (∼41 kyr), and eccentricity (∼100 kyr, ∼200 kyr, and ∼400 kyr) forcings since the late Pliocene. The continuous precession and obliquity signals, with their comparable variance contributions, directly demonstrate the combined influences of high-latitude ice-volume and low-latitude insolation forcings on the monsoon climatic variations. Basin subsidence and adequate sediment supply have an important impact on the preservation of high-frequency signals, resulting in higher amplitudes of precession oscillations during ∼3.5–3.3 Ma and after ∼2 Ma. In addition, the intensified ∼100 kyr sedimentary cycles are proposed to originate from the bundling of several precession or obliquity cycles, which correlates with the development of fluvial layers under changing environmental conditions. The new record provides new insights into the interactive effects of tectonic processes and climatic changes on orbital-scale sedimentary cycles in this region.

沉积物中保存的不明确的高频进动旋回归因于构造和沉积后扰动，阻碍了对地表系统对区域气候变化的直接响应的全面理解。为了解决这一问题，本研究对渤海湾盆地西部地区一个保存完好的河湖层序进行了研究。通过高分辨率古地磁测年和伽马数据的小波分析，评价了区域沉降和季风气候变化对沉积旋回的影响。结果显示，自上新世晚期以来，显著的沉积旋回响应于岁差（~ 21 kyr）、倾角（~ 41 kyr）和偏心率（~ 100 kyr、~ 200 kyr和~ 400 kyr）强迫。连续的进动和倾角信号及其可比较的方差贡献，直接证明了高纬度冰量和低纬度日照强迫对季风气候变化的联合影响。盆地沉降和充足的沉积物供应对高频信号的保存有重要影响，导致在~ 3.5-3.3 Ma和~ 2 Ma之后的进动振荡幅度更高。此外，强烈的~ 100 kyr沉积旋回起源于多个旋进旋回或斜旋回的合并，这与河流层在变化的环境条件下的发育有关。这一新记录为构造过程和气候变化对该地区轨道尺度沉积旋回的相互作用提供了新的认识。

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引用次数: 0

Early Carboniferous tectonic setting of the Kalamaili suture Zone, north Junggar (NW China): Constraints from the volcanic rocks in the geological section of Songkaersu Formation 准噶尔北部卡拉麦里缝合带早石炭世构造背景：松凯尔苏组地质剖面火山岩的约束

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.2026.106950

Qianru Cai , Jinduo Wang , Guanlong Zhang , Zhengrong Xiong , Hongzhou Yu , Jian Zhou , Zhihua Song

The mid-Early Carboniferous period characterized by widespread magmatism represents a key tectonic transition stage for the Kalamaili suture zone of Northeastern Junggar. Debates persist on the petrogenesis and tectonic setting of these Early Carboniferous igneous rocks, restricting our understanding of the Late Paleozoic tectonic evolution. In this study, we performed integrated geochronological and geochemical analyses on intermediate-basic volcanic rocks of the Songkaersu Formation from the Shuangjingzi North and Xidagou South profiles along the southern Kalamaili suture zone. Zircon U-Pb dating of three samples constrains magmatic activity to 344–332 Ma. The rocks comprise basalt, basaltic andesite, and andesite, exhibiting calc-alkaline affinity. Their geochemical compositions demonstrate variable SiO₂ (46.76–62.87 wt%), MgO (1.49–6.42 wt%), and K₂O (0.23–3.68 wt%), moderate TiO₂ (0.42–1.19 wt%), and elevated Na₂O (2.89–5.85 wt%) and P₂O₅ (0.21–0.59 wt%) contents. Enrichment in large-ion lithophile elements (LILEs: Rb, Ba, K) and light rare earth elements (LREEs), coupled with depletion in high-field-strength elements (HFSEs: Nb, Ta, Ti), suggests arc-related affinity. Radiogenic isotope signatures reveal low initial ⁸⁷Sr/⁸⁶Sr ratios (0.7039–0.7043) and significant variations in ε_Nd (t) (+5.0 – +7.5) and ε_Hf (t) values (+0.05 – +12.62). These features imply derivation from partial melting of previously subducted slab-derived fluids metasomatized depleted mantle lithosphere. The integrated geochemical and isotopic patterns, combined with evidence of mantle material upwelling driven by lithospheric thinning, indicate a post-collisional intraplate tectonic setting. Collectively, these results suggest that the northeastern Junggar Basin transitioned to a post-collisional regime by at least the middle Early-Carboniferous.

中早石炭世是准噶尔东北部卡拉麦里缝合带的重要构造过渡时期，岩浆活动广泛存在。这些早石炭世火成岩的成因和构造背景一直存在争议，限制了我们对晚古生代构造演化的认识。本文对沿卡拉麦里缝合带南部双井子北剖面和西大沟南剖面松凯尔苏组中基性火山岩进行了年代学和地球化学综合分析。三个样品的锆石U-Pb定年限制了岩浆活动在344 ~ 332 Ma之间。岩石包括玄武岩、玄武岩安山岩和安山岩，具有钙碱性亲和力。其地球化学成分表现为SiO2 （46.76 ~ 62.87 wt%）、MgO （1.49 ~ 6.42 wt%）、K2O （0.23 ~ 3.68 wt%）含量变化，TiO2 （0.42 ~ 1.19 wt%）含量适中，Na2O （2.89 ~ 5.85 wt%）和P2O5 （0.21 ~ 0.59 wt%）含量升高。大离子亲石元素（LILEs: Rb, Ba， K）和轻稀土元素（LREEs）富集，高场强元素（hfse: Nb, Ta, Ti）耗损，表明弧相关亲和力。放射性成因同位素特征显示，初始87Sr/86Sr比值（0.7039 ~ 0.7043）较低，εNd (t)（+5.0 ~ +7.5）和εHf (t)值（+0.05 ~ +12.62）变化显著。这些特征意味着源自先前俯冲的板块衍生流体的部分熔融，这些流体交代了枯竭的地幔岩石圈。综合地球化学和同位素模式，结合岩石圈变薄驱动的地幔物质上涌的证据，表明了碰撞后的板内构造背景。总之，这些结果表明，准噶尔盆地东北部至少在早石炭世中期过渡到后碰撞状态。

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引用次数: 0

The Earth magnetic field in the Mesoproterozoic – a new assessment of paleomagnetic secular variation from Arctic Siberia, Russia 中元古代地球磁场——对俄罗斯西伯利亚北极地区古地磁长期变化的新评价

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.2026.106951

Aleksandr Pasenko , Ivan Lebedev , Dmitrii Ushakov

The hypothesis that the Earth’s magnetic field can be approximated by a time-averaged geocentric axial dipole (GAD) allows paleomagnetic data to be used in developing paleogeographic reconstructions. For the Precambrian, this hypothesis needs to be tested for different time intervals. On the other hand, information on the evolution of the geomagnetic field during the Precambrian can be used to shed light on the processes of deep geodynamics and the evolution of the Earth’s core. One of the numerical parameters characterizing the state of the geomagnetic field is the amplitude of the paleosecular variations (PSV), estimated from the scatter of the directions of the natural remanent magnetization. We propose a new estimate of PSV amplitude calculated for low latitudes of ∼1.5 Ga over 36 individual sites, which is unique for such determinations in the Precambrian. Our new estimate of S_b =

10.2 \frac{13.0}{9.5}

° is consistent with recent G-models for Precambrian. It indicates that in the Mesoproterozoic, the contribution of symmetric magnetic field components to geomagnetic variations was comparable to the Mesozoic and to the present-day.

地球磁场可以用时间平均地心轴向偶极子（GAD）来近似的假设，使得古地磁数据可以用于发展古地理重建。对于前寒武纪，这个假设需要在不同的时间间隔内进行检验。另一方面，关于前寒武纪地磁场演化的信息可以用于揭示深部地球动力学过程和地核演化。表征地磁场状态的数值参数之一是古长期变化幅度（PSV），它是由自然剩余磁化方向的散射估计的。我们提出了一个新的估计，在36个单独的地点上计算了低纬度~ 1.5 Ga的PSV振幅，这在前寒武纪的此类确定中是独一无二的。我们对Sb = 10.213.09.5°的新估计与最近的前寒武纪g模型一致。表明在中元古代，对称磁场分量对地磁变化的贡献与中生代和现代相当。

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引用次数: 0

Integrated seismic hazard assessment around Qom City, North-Central Iran, based on earthquake focal mechanisms, fault-slip data, and deterministic analysis 基于震源机制、断层滑动数据和确定性分析的伊朗中北部库姆市周边地震危险性综合评估

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2026-01-02 DOI: 10.1016/j.jseaes.2025.106945

Mohadese Ajami, Abdollah Sohrabi-Bidar, Reza Nozaem

Iran is located in the central part of the Alpine-Himalayan orogenic belt, experiencing significant and destructive earthquakes throughout its history. Obviously, major and strategically important cities hold great significance in the event of an earthquake, considering their political and social importance. Among the important cities of Iran, Qom is a populous and significant city in the northern part of the central Iranian zone. This paper presents a seismotectonic assessment by examining and analyzing seismic and fault-slip data to determine the average attitude of the principal stress tensors within a 150 km radius of Qom city. Next, these findings were integrated with the results of deterministic seismic analysis and utilized in the Fault Motion Potential (FMP) method to evaluate the risk level of major surrounding faults in Qom. Modern and paleostress assessments determined that the trend of the maximum principal stress axis is about N30E, approximately aligning with the current convergence of the Arabian-Eurasian plates in central Iran. Consequently, under such a dominant stress regime, the movement capacity of a fault is directly linked to the relation between fault geometry and the main stress axes. Furthermore, fault length and its distance to the site are key parameters for assessing the potential seismic hazard based on the evaluation of a Deterministic risk event. Deterministic risk study identified Qom, Alborz, and Haji-Abad faults as the most seismic risk influencing factors in the region. Fault motion potential (FMP) values were computed for these faults by using modern and paleostress data with respect to each fault pole geometry. The outcome of our study indicated that the Qom and Alborz faults have high reactivation potential for earthquake generation, with FMP values of 0.6 and 0.7, respectively. In contrast, the Haji-Abad fault, with an FMP value of 0.3, represents a moderate seismic risk level. Earthquakes that occur along this fault can reach magnitudes up to 7.2 Mw. The results of this research can be used in the urban development programming of Qom, and adjacent areas.

伊朗位于阿尔卑斯-喜马拉雅造山带的中部，在其历史上经历了重大和破坏性的地震。显然，考虑到它们的政治和社会重要性，具有重要战略意义的大城市在地震事件中具有重要意义。在伊朗的重要城市中，库姆是伊朗中部地区北部人口众多的重要城市。本文通过对地震和断层滑动资料的检查和分析，提出了一种地震构造评价方法，以确定库姆市半径150公里范围内主应力张量的平均姿态。然后，将这些发现与确定性地震分析结果相结合，应用于断层运动势（FMP）方法评价库姆周边主要断层的风险等级。现代和古应力评估表明，最大主应力轴的走向约为N30E，与目前阿拉伯-欧亚板块在伊朗中部的汇聚方向大致一致。因此，在这种主导应力状态下，断层的运动能力与断层几何形状与主应力轴之间的关系直接相关。此外，基于确定性风险事件的评价，断层长度和断层到场地的距离是评估潜在地震危险性的关键参数。确定性风险研究确定Qom、Alborz和Haji-Abad断裂是该地区地震风险影响最大的因素。利用现代和古应力资料，根据各断裂极的几何形状计算了断层运动电位。研究结果表明，库姆断裂和阿尔博斯断裂具有较高的地震再激活潜力，FMP值分别为0.6和0.7。相比之下，Haji-Abad断层的FMP值为0.3，代表中等地震风险等级。沿着这条断层发生的地震震级可达7.2兆瓦。研究结果可用于库姆及邻近地区的城市发展规划。

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引用次数: 0