Journal of Asian Earth Sciences最新文献_第4页

The main Paleo-Tethys Ocean suture in the Pamir Region: Revealed by detrital zircon U–Pb geochronology 帕米尔地区古特提斯洋主缝合线：由碎屑锆石U-Pb年代学揭示

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106921

Murodov Azamdzhon , Wei Dan , Xin Ma , Murodov Davlatkhudzha , Sharifjon Odinaev , Ilhomjon Oimuhammadzoda , Mustafo Gadoev , Upendra Baral , Dzhovid Yogibekov , Gong-Jian Tang

The Pamir Plateau offers valuable insights into the evolution of the Tethys Oceans. Despite numerous studies, the nature and timing of closure of the Paleo–Tethys Ocean remain debated. This study presents detrital zircon U–Pb ages of sedimentary rocks across the Pamir terranes to investigate their tectonic evolution. Detrital zircons from the Paleozoic–Triassic sedimentary succession in the Northern and Central Pamir yielded similar results, with ages ranging from ∼ 233 Ma to 1000 Ma, showing two major peaks one at ∼ 250 Ma and another at 540–600 Ma. Zircons giving these two age peaks are subhedral to anhedral, implying they were likely derived from arc–related magmatic rocks, possibly formed by the subduction of the Paleo–Tethys oceanic lithosphere. In contrast, detrital zircons from the Late Triassic sandstone in Southern Pamir reveal a major peak at 237 Ma, with subordinate peaks at ∼ 430 Ma and 540 Ma, indicating their detritus was largely sourced from the Central Pamir. Age patterns of the detrital zircons from the Northern–Central Pamir and South Pamir are similar to those of the North and South Qiangtang, respectively, indicating that the Rushan–Pshart suture zone was the main suture of the Paleo–Tethys, and the Tanymas suture zone was the back–arc basin of the Paleo–Tethys Ocean.. The obtained data indicate that the northward subduction of the Paleo–Tethys oceanic lithosphere beneath the Northern and Central Pamir was continuous, at least during the Late Devonian to Triassic period, and the collision between the Central and South Pamir was initiated in the Middle Triassic (∼240 Ma).

帕米尔高原为特提斯海洋的演变提供了宝贵的见解。尽管进行了大量的研究，古特提斯洋的性质和关闭时间仍然存在争议。本文研究了帕米尔地体沉积岩的碎屑锆石U-Pb年龄，以探讨其构造演化。来自帕米尔高原北部和中部古生代-三叠纪沉积序列的碎屑锆石也得到了类似的结果，年龄范围从~ 233 Ma到1000 Ma，显示出两个主要峰，一个在~ 250 Ma，另一个在540-600 Ma。给出这两个年龄峰的锆石均为半面体到正面体，表明它们可能来自与弧相关的岩浆岩，可能是由古特提斯洋岩石圈俯冲形成的。南帕米尔高原晚三叠世砂岩碎屑锆石在237 Ma有主峰，在~ 430 Ma和540 Ma有次峰，表明其碎屑主要来自中帕米尔高原。北-中帕米尔和南帕米尔的碎屑锆石年龄模式分别与北羌塘和南羌塘相似，表明如山-普沙特缝合带是古特提斯的主缝合带，坦尼马斯缝合带是古特提斯洋的弧后盆地。得到的资料表明，至少在晚泥盆世至三叠纪期间，古特提斯洋岩石圈在北帕米尔高原和中帕米尔高原的北俯冲是连续的，而中帕米尔高原和南帕米尔高原的碰撞始于中三叠世（~ 240 Ma）。

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引用次数: 0

Crustal structure of Sulaimaniyah, NE Iraq: Joint analysis of receiver functions and surface wave dispersion 伊拉克东北部苏莱曼尼亚的地壳结构：接收函数和面波频散的联合分析

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106920

Suad Mohammed Ali , Emad H. Al-Khersan , Hayder I. Mohammed

The Sulaimaniyah region in northeastern Iraq lies within the seismically active Zagros Fold-Thrust Belt (ZFTB), formed by the ongoing collision between the Arabian and Eurasian plates. Despite its tectonic significance, detailed shear-wave velocity models for this area remain scarce, which limits our understanding of the crustal composition, thickness, and deformation mechanisms. This study presents a new, well-constrained crustal structure model for the region, achieved through the novel integration of P-wave receiver functions and Rayleigh wave group velocity dispersion in a joint inversion framework. It also offers an important understanding of the region’s tectonic framework and its significance for hydrocarbon formation and distribution. The aim is to achieve high-resolution constraints on crustal layering and Moho depth beneath the Sulaimaniyah (SLY) seismic station. Data from nine high-quality teleseismic events and 20 carefully selected Rayleigh wave dispersion curves were processed using the Computer Programs in Seismology (CPS) package. The results reveal a four-layered crust: a 10 km-thick sedimentary layer (Vs ≈ 3.1 km/s), an upper crustal layer at 14–16 km (Vs ≈ 3.3 km/s), a mid-crust at 30–32 km (Vs ≈ 3.4–3.5 km/s), and the Moho at ∼ 46 km depth, separating the lower crust (Vs ≈ 3.6 km/s) from the uppermost mantle (Vs ≈ 3.9 km/s). The model also shows a gradational Moho transition, unlike abrupt boundaries observed in some regional sites, suggesting elevated temperatures or crustal fracturing due to active collision processes. This work provides researchers with a robust reference model for the ZFTB sector of Iraq, thereby enhancing seismic hazard assessment, tectonic modelling, and comparative studies of continental collision zones.

伊拉克东北部的苏莱曼尼亚地区位于地震活跃的扎格罗斯褶皱冲断带（ZFTB）内，该带是由阿拉伯板块和欧亚板块持续碰撞形成的。尽管具有重要的构造意义，但该地区详细的剪切波速度模型仍然缺乏，这限制了我们对地壳组成，厚度和变形机制的理解。本研究通过在联合反演框架中整合p波接收函数和瑞利波群速度频散，提出了该地区一个新的、约束良好的地壳结构模型。对该区的构造格架及其对油气形成和分布的意义也有重要的认识。目的是实现苏莱曼尼亚（SLY）地震台站下地壳分层和莫霍深度的高分辨率约束。使用计算机程序在地震学（CPS）软件包处理了9个高质量的远震事件和20个精心挑选的瑞利波频散曲线的数据。结果显示，地壳为4层：10 km厚的沉积层（Vs≈3.1 km/s）， 14-16 km （Vs≈3.3 km/s）的上地壳层，30-32 km （Vs≈3.4-3.5 km/s）的中地壳，以及约46 km深度的莫霍层，将下地壳（Vs≈3.6 km/s）与上地幔（Vs≈3.9 km/s）分开。该模型还显示了一个渐变的莫霍转变，不像在某些区域观测到的突然边界，这表明由于活跃的碰撞过程，温度升高或地壳破裂。这项工作为伊拉克ZFTB部门的研究人员提供了一个强大的参考模型，从而加强了地震危险性评估、构造建模和大陆碰撞带的比较研究。

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引用次数: 0

Mass transport deposits in confined environment, a case study from the Kaiping sag, Pearl River Mouth basin, northern south China sea margin 封闭环境下的块体搬运沉积——以南海北部珠江口盆地开平凹陷为例

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106924

Lushan Jiang, Xiwu Luan

Mass transport deposits (MTDs) have been extensively discussed in the literature. The prevailing understanding characterizes MTDs as gravity-driven instability phenomena occurring on the seafloors. This study employs high-resolution 2D/3D seismic data integrated with well data to re-evaluate the genesis mechanisms of MTDs in the Kaiping sag, Zhu-II depression, Pearl River Mouth basin (PRMB), northern margin of the South China Sea (SCS). Key diagnostic features interpreted from seismic datasets reveal the absence of typical characteristics of conventional MTDs, including no distinct headwall scarps, and moats, and especially no onlapping structures of isochronous turbidite contourites that usually cover uneven MTD surfaces. In contrast, seismic evidence for a tectonic compression environment is observed, such as thrust fault reactivation, localized stratal folding, and chaotic thrust-related deformation patterns within the study interval-consistent with the post-spreading tectonic setting of the SCS. For the first time, this research concludes that these MTDs formed in a confined environment (rather than an open continental slope), and were induced by mega-earthquakes. The key contributing factors to their formation include: (1) tectonic compression after the cessation of SCS seafloor spreading (post-16 Ma), evidenced by seismic records of thrusting and folding; (2) elevated sedimentation rates since the peak uplift of the eastern Tibetan plateau (since 15 Ma), leading to thick unconsolidated sediments; (3) periods of higher sea level (favouring high pore-water pressure); and (4) mega-earthquakes triggered by the post-spreading compression. Collectively, these factors facilitated the liquefaction processes that drove MTDs development.

质量搬运沉积（MTDs）在文献中得到了广泛的讨论。目前普遍的理解是，MTDs是发生在海底的重力驱动的不稳定现象。利用高分辨率二维/三维地震资料，结合钻井资料，对南海北缘珠江口盆地开平凹陷、珠二坳陷、开平凹陷的MTDs成因机制进行了重新评价。从地震数据集解释的关键诊断特征显示，传统MTD缺乏典型特征，包括没有明显的顶壁陡坡和护城河，特别是没有覆盖不均匀MTD表面的等时浊积等高线的重叠结构。相反，在研究区间内观察到逆冲断层重新激活、局部地层褶皱和与逆冲相关的混乱变形模式等构造压缩环境的地震证据，与南海扩张后的构造环境相一致。这项研究首次得出结论，这些MTDs形成于一个封闭的环境（而不是一个开放的大陆斜坡），并且是由大地震引起的。其形成的关键因素有：(1)南海海底扩张停止后（16 Ma以后）的构造挤压作用，以逆冲和褶皱地震记录为证据；(2)青藏高原东部自15 Ma以来峰值隆升，沉积速率升高，形成较厚的松散沉积；(3)高海平面时期（有利于高孔隙水压力）；(4)伸展后压缩引发的特大地震。总的来说，这些因素促进了液化过程，推动了mtd的发展。

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引用次数: 0

Eocene SSZ-type ophiolite from Banggi Island, Sabah (Northern Borneo), Malaysia: Zircon U-Pb ages, geochemical characteristics and tectonic implications 马来西亚沙巴（北婆罗洲）邦吉岛始新世ssz型蛇绿岩：锆石U-Pb年龄、地球化学特征及构造意义

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106919

Rezal Rahmat , Sun-Lin Chung , Azman Abd Ghani , Hao-Yang Lee , Yoshiyuki Iizuka , Chih-Tung Chen , Long Xiang Quek

Ophiolites in Sabah are dispersed in a band-shaped lineament stretching from Darvel Bay in the southeast to Banggi Island in the northmost part of Sabah. This study reports the first set of zircons U-Pb ages and whole-rock geochemical data of the Banggi Island Ophiolite (BIO), conventionally regarded as part of the regional Triassic-Eocene “Chert-Spilite Formations” that had been named as the Sabah Ophiolite, and interpreted as remnants of oceanic crust from the proto-South China Sea. LA-ICPMS analyses of zircons separated from five gabbro and two diorite samples gave a short span of ²⁰⁶Pb/²³⁸U ages of ∼ 55–50 Ma (Early Eocene), with high and positive ε_Hf(t) values from + 16.6 to + 10.2 indicating their magma source from a relatively depleted or juvenile mantle. The crustal sequence of Banggi Island Ophiolite, including basalt, gabbro, and diorite, is characterized by depletion in the light rare earth elements and various degrees of enrichment in the large ion lithophile elements, coupled with depletion in Nb and Ta. Their overall geochemical signatures are comparable to the SSZ (supra-subduction zone)-type ophiolites reported from two nearby islands in Palawan and Mindoro, western Philippines. Integrating our new data with regional geologic information, we argue that the Banggi Island Ophiolite represents an SSZ-type ophiolite that formed in the forearc regime at the initial stage of southward subduction of the proto-South China Sea plate. The subduction initiation started from the Early Eocene in Sabah, leading to upper-plate spreading and associated magmatism that gave rise to the crustal rocks of the ophiolite. It may have caused a regional stratigraphic unconformity and later propagated eastward to Palawan and Mindoro, eventually resulting in the ophiolites there and a volcanic arc exposed now as the Cagayan Ridge.

沙巴蛇绿岩呈带状分布，从东南部的Darvel Bay延伸至最北部的Banggi Island。本文报道了Banggi Island蛇绿岩（BIO）的第一套锆石U-Pb年龄和全岩地球化学数据，该蛇绿岩通常被认为是三叠纪-始新世区域“燧石-碧岩组”的一部分，被命名为Sabah蛇绿岩，被解释为原南海海洋地壳的残余。从5个辉长岩和2个闪长岩样品中分离出的锆石LA-ICPMS分析结果显示，锆石的206Pb/238U年龄跨度较短，为~ 55 ~ 50 Ma（早始新世），εHf(t)值在+ 16.6 ~ + 10.2之间，εHf(t)值较高且正，表明其岩浆来源为相对枯竭或幼年地幔。邦基岛蛇绿岩的地壳序列包括玄武岩、辉长岩和闪长岩，其特征是轻稀土元素亏缺，大离子亲石元素有不同程度的富集，并伴有Nb和Ta的亏缺。其整体地球化学特征与在菲律宾西部巴拉望岛和民都洛岛附近报道的SSZ（超俯冲带）型蛇绿岩相当。结合区域地质资料，我们认为邦基岛蛇绿岩是一种形成于原南海板块向南俯冲初期弧前状态的ssz型蛇绿岩。沙巴早始新世开始俯冲，板块扩张，岩浆作用形成蛇绿岩类地壳岩石。它可能造成了区域地层不整合，后来向东传播到巴拉望岛和民都洛岛，最终形成了那里的蛇绿岩和一条火山弧，现在暴露为卡加延岭。

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引用次数: 0

Late Triassic ore-forming adakitic porphyries from post-collisional lithospheric extension in the eastern Kunlun Orogen, northern Tibet 藏北东昆仑造山带碰撞后岩石圈伸展中的晚三叠世艾达质斑岩成矿

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106922

Jinyang Zhang , Zhongyuan Ma , Yong Zhang , Jianxun Yuan , Jiaxing Chai , Lanxin Zhang , Changqian Ma , Jianwei Li , Yuanming Pan

Post-collisional porphyry Cu systems are commonly associated with adakitic intrusions and lithospheric extension. In this study, Wulanwuzhu’er porphyritic diorites and Yazigou dolerites have been investigated to support Late Triassic adakitic rocks for porphyry Cu systems of the eastern Kunlun Orogen formed in post-collisional lithospheric extension. The porphyritic diorites emplaced as dykes at 211–214 Ma are ‌spatiotemporally and genetically related to the epithermal Ag-Pb-Zn mineralization. The diorites contain high Al₂O₃ hornblende (up to 13.74 wt%) and belong to metaluminous and high-K calc-alkaline series with moderately high Sr/Y values and enriched Nd isotopes. They were most likely derived from a moderately oxidized metasomatic lithosphere mantle under a post-collisional setting, with adakitic signatures caused by hornblende crystallization at the lower crust. The dolerite dykes (222 ± 1.3 Ma) are metaluminous and calc-alkaline with high Mg#, Ni (up to 103 ppm), and ε_Nd(t) values (up to 6.1). They were originated from a depleted mantle in the spinel stability field with small melting degrees, supporting a significant upwelling of the asthenosphere to induce the post-collisional lithospheric extension. Systematic compilation of regional geochemical data in the orogen suggests that Late Triassic adakitic intrusions in the eastern section have higher MgO and Ni contents and oxygen fugacities than the counterparts in the western section, probably indicating a slab tearing model. Vigorous lower crustal magmatic processes in a thickened continental crust, the post-collisional slab tearing, and oxidized sources of metasomatic mantle or subducted slab for the eastern Kunlun Orogen are favorable for porphyry Cu mineralization.

碰撞后斑岩型铜体系通常与埃达质侵入和岩石圈伸展有关。本文研究了东昆仑造山带碰撞后岩石圈伸展形成的斑岩-铜体系中，乌兰五柱二斑岩闪长岩和雅兹沟斑岩支持晚三叠世埃达质岩。在211 ~ 214 Ma成脉侵位的斑岩闪长岩在时空和成因上与浅成热液银铅锌成矿作用有关。闪长岩含高Al2O3角闪石（重达13.74 wt%），属铝质、高钾钙碱性系列，Sr/Y值中等，Nd同位素富集。它们很可能来自于碰撞后环境下的中度氧化交代岩石圈地幔，具有下地壳角闪石结晶引起的绿质特征。白云岩岩脉（222±1.3 Ma）具有高Mg#、高Ni（可达103 ppm）、高εNd(t)值（可达6.1）的铝质钙碱性。它们起源于尖晶石稳定场的枯竭地幔，熔融程度小，支持软流圈的明显上升流，诱发碰撞后岩石圈扩张。对造山带区域地球化学资料的系统整理表明，东段晚三叠世埃达质岩体的MgO、Ni含量和氧逸度均高于西段的同类岩体，可能具有板块撕裂模式。东昆仑造山带加厚大陆地壳中剧烈的下地壳岩浆作用、碰撞后的板块撕裂作用以及交代地幔或俯冲板块的氧化源均有利于斑岩型铜成矿。

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引用次数: 0

The Sarma segment of the Akitkan orogenic Belt, Siberian craton: Milestones of the Archean-Proterozoic history 西伯利亚克拉通阿基特坎造山带萨尔马段：太古宙-元古宙历史的里程碑

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-19 DOI: 10.1016/j.jseaes.2025.106923

Uliana S. Efremova, Tatiana V. Donskaya, Dmitrii P. Gladkochub, Anatolii M. Mazukabzov, Elena I. Demonterova, Alexei V. Ivanov, Nikolay V. Bryansky

New constraints on local geology, geochemistry, and geochronology (LA-ICP-MS U-Pb detrital zircon ages) have been obtained for metamorphic clastic rocks assigned previously to the Khargitui Formation, presumably the oldest clastic rocks in the Sarma segment of the Akitkan orogenic belt in the southern Siberian craton. The new data reveal three units of rocks formed at different stages of the Akitkan orogen evolution. Unit 1 includes mainly leucocratic gneisses derived from 2.7–2.5 Ga polymictic sandstones or graywackes. These sediments were deposited upon the basement of the Sarma terrane composed of 2.88 Ga TTG granitoids that became the source of clastic material. Unit 2 consists of quartzite and schists produced by metamorphism of quartz and polymictic sandstones and siltstones. Judging by the ages of detrital zircons from mica-quartz schists, along with the age of metamorphism, the deposition of the sedimentary protoliths lasted from 2.15 to 1.95 Ga. It was maintained by destruction of felsic rocks within the Sarma terrane prior to the collisional event that led to the formation of the Akitkan orogen. Unit 3 likewise includes quartzites and schists but those derived from more mature sediments. The clastic material predominantly originated from 1.88–1.84 Ga rocks of the South Siberian magmatic belt and was deposited in intracontinental basins between 1.00 and 0.72 Ga, after the assembly of the Siberian craton. Synthesis of new and published data for the Sarma rocks allow tracing the Archean-Proterozoic history of the Akitkan orogen, including the pre- and post-orogenic stages of its development.

对西伯利亚克拉通南部阿基特坎造山带Sarma段最古老的变质碎屑岩Khargitui组进行了局部地质、地球化学和年代学研究（LA-ICP-MS U-Pb碎屑锆石年龄）。新的数据揭示了在阿基特坎造山带演化的不同阶段形成的三种岩石单位。第1单元主要包括来自2.7-2.5 Ga多晶砂岩或灰岩的白垩系片麻岩。这些沉积物沉积在由2.88 Ga TTG花岗岩类组成的萨尔马地块基底上，成为碎屑物质的来源。第二单元由石英变质作用产生的石英岩和片岩与多晶砂岩和粉砂岩组成。根据云母-石英片岩碎屑锆石的年龄和变质作用年龄判断，沉积原岩的沉积时间为2.15 ~ 1.95 Ga。在导致阿基特坎造山带形成的碰撞事件发生之前，它是由萨尔马地块内的长英质岩石的破坏维持的。第三单元同样包括石英岩和片岩，但它们来自更成熟的沉积物。碎屑物质主要来源于南西伯利亚岩浆带1.88 ~ 1.84 Ga的岩石，沉积于1.00 ~ 0.72 Ga之间的陆内盆地，是西伯利亚克拉通拼合后形成的。对萨尔马岩石的新数据和已发表的数据进行综合，可以追溯阿基特坎造山带的太古代-元古代历史，包括造山带发育的前和后阶段。

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引用次数: 0

Corrigendum to “Architecture and evolution of the carbonate platform margin of the Lower Cambrian Xiaoerbrak Formation, northwestern Tarim Basin, China” [J. Asian Earth Sci. 274 (2024) 106279] “塔里木盆地西北部下寒武统小尔布拉克组碳酸盐岩台地边缘构造与演化”勘误[J]。亚洲地球科学，274 (2024)106279

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-18 DOI: 10.1016/j.jseaes.2025.106912

Ziyi Wang, Zhiqian Gao, Tailiang Fan

引用次数: 0

The Lithosphere-Atmosphere-Ionosphere coupling (LAIC) processes around the 2024 Wushi (China) Mw7.1 earthquake 2024年中国吴市Mw7.1级地震前后岩石圈-大气-电离层耦合过程

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-16 DOI: 10.1016/j.jseaes.2025.106916

Xuemin Zhang , Angelo De Santis , Pan Xiong , Gianfranco Cianchini , Aisa Yisimayili , Saioa A. Campuzano , Na Yang , Serena D’Arcangelo , Jing Liu , Mariagrazia De Caro , Xinyan Li , Cristiano Fidani , Muping Yang , Martina Orlando , Xinyang Ouyang , Loredana Perrone , Hong Liu , Dario Sabbagh , Maoning Feng , Maurizio Soldani , Shukai Wang

This paper presents a comprehensive analysis on multiple parameters in the lithosphere, atmosphere and ionosphere, around the Wushi M_w7.1 earthquake that occurred on 22 January 2024, in Xinjiang, China. Typical perturbations were picked up with different methods, with a limited time period for lithospheric parameters of longer than 3 years, 90 days before and 10 days after for most atmospheric and ionospheric parameters, in a limited distance within Dobrovolsky’s area of about 1000 km. All the results show that about 60 anomalies were detected before the Wushi earthquake, with medium-term ones lasting about 1 year in the lithosphere, and short-term ones within 3 months in the atmosphere and ionosphere, where the outgoing long wave radiation covered the earthquake occurrence time from four days before to four days after, considered an imminent indicator. The thrust focal mechanism of this earthquake helps to explain the anisotropic feature in Earth’s resistivity and orientation in the electric field, and also the weak variations in the b-value. By combining ground-based and spaceborne observations, a few parameters clearly illustrated the approaching earthquake location, which makes a certain contribution to future earthquake prediction. The accumulating rate of all the anomalies exhibited a fast exponential trend, which illustrates both direct and indirect lithosphere-atmosphere–ionosphere coupling mechanisms during the preparation stage of the Wushi earthquake.

本文对发生在2024年1月22日新疆乌市Mw7.1级地震前后的岩石圈、大气和电离层多个参数进行了综合分析。典型的摄动是用不同的方法采集的，岩石圈参数的时间限制在3年以上，大多数大气和电离层参数的时间限制在90天之前，10天之后，在大约1000公里的Dobrovolsky区域内的有限距离内。结果表明，乌市地震前共探测到60次异常，其中岩石圈中期异常持续1年左右，大气和电离层短期异常持续3个月左右，向外发射的长波辐射覆盖了地震发生前4天至震后4天的时间，可视为即将发生的信号。这次地震的逆冲震源机制有助于解释地球在电场中的电阻率和方位的各向异性特征，以及b值的微弱变化。通过地基观测和星载观测相结合，几个参数清晰地说明了即将来临的地震位置，对未来的地震预报有一定的贡献。所有异常的累积速率均呈快速指数趋势，说明了乌市地震准备阶段岩石圈-大气-电离层的直接和间接耦合机制。

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引用次数: 0

Petrogenesis of early Silurian I-type granitoids in the Nanling domain, South China: implications for the evolution of the Wuyi-Yunkai orogen 南岭地区早志留世ⅰ型花岗岩成因及其对武夷-云开造山带演化的启示

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-16 DOI: 10.1016/j.jseaes.2025.106917

Hai Jiang , Shao-Yong Jiang

A long-standing debate exists over the petrogenesis of Early Paleozoic granites of the South China Block, with the main issue being whether these granites originated from intracontinental orogenic processes. Here, we report new zircon U-Pb geochronology, whole-rock geochemistry, and Sr-Nd-Hf isotope data for two Silurian I-type granitoids in the Nanling domain, South China. The Meiziwo pluton, comprising granodiorite and monzogranite, and the Yaoling quartz porphyry have identical zircon U-Pb ages of ∼ 433 Ma. Rocks of both the Meiziwo and Yaoling plutons have I-type geochemical affinities and are metaluminous to peraluminous in composition (A/CNK = 0.94–1.27). They have low P₂O₅ contents that are negatively correlated with SiO₂. They show chondrite-normalized rare earth element (REE) patterns with LREE enrichment and moderately negative Eu anomalies (Eu/Eu* = 0.50–0.73). They display enrichments in Rb, Th, U, and Pb, and depletions in Ba, Nb, Sr, and Ti in primitive mantle normalized plots. They also have high ⁸⁷Sr/⁸⁶Sr_i ratios (0.712160–0.715776), low ε_Nd(t) (−10.9 to −8.8) and zircon ε_Hf(t) (−12.5 to −6.3) values, indicative of derivation from partial melting of an ancient mafic lower crust, modified by crystal fractionation. The degree of fractionation in the Yaoling quartz porphyry lies intermediate between that of the Meiziwo granodiorite and monzogranite. It is proposed that the Wuyi-Yunkai orogeny originated as an intracontinental orogeny, likely linked to the far-field effects of plate interaction along the northern margin of eastern Gondwana. Widespread post-orogenic felsic magmatism with subordinate mafic components (ca. 435–415 Ma) marks a tectonic transition from compression to extension. This shift is interpreted to reflect lithospheric delamination and the initiation of intracontinental extension in the region.

关于华南地块早古生代花岗岩的岩石成因一直存在争议，主要争论的焦点是这些花岗岩是否起源于陆内造山作用。本文报道了南岭地区2个志留系i型花岗岩的锆石U-Pb年代学、全岩地球化学和Sr-Nd-Hf同位素数据。由花岗闪长岩和二长花岗岩组成的梅子窝岩体与耀岭石英斑岩锆石U-Pb年龄相同，均为~ 433 Ma。梅子窝和窑岭岩体的岩石具有i型地球化学亲和性，在组成上为铝质-过铝质（A/CNK = 0.94 ~ 1.27）。P2O5含量低，与SiO2呈负相关。稀土元素呈球粒正态化模式，LREE富集，Eu中负异常（Eu/Eu* = 0.50 ~ 0.73）。原始地幔归一化区Rb、Th、U、Pb富集，Ba、Nb、Sr、Ti缺失。它们具有较高的87Sr/86Sri比值（0.712160 ~ 0.715776），较低的εNd(t)值（- 10.9 ~ - 8.8）和锆石εHf(t)值（- 12.5 ~ - 6.3），表明它们来源于古基性下地壳的部分熔融，并经过晶体分选修正。窑岭石英斑岩的分选程度介于梅子窝花岗闪长岩和二长花岗岩之间。武夷-云凯造山运动起源于陆内造山运动，可能与冈瓦纳东部北缘板块相互作用的远场效应有关。广泛的造山后长英质岩浆活动（约435 ~ 415 Ma）标志着构造由挤压向伸展转变。这种转变被解释为反映了岩石圈的剥离和该地区大陆内伸展的开始。

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引用次数: 0

Fe occupancy in zoned ferroan dolomite and its constraints on dolomite ordering process: a case study on micritic dolostone of Ordovician Majiagou formation in eastern Ordos Basin, China 带状铁质白云岩中铁的占比及其对白云岩排序的制约——以鄂尔多斯盆地东部奥陶系马家沟组泥晶白云岩为例

IF 2.4 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Asian Earth Sciences

Pub Date : 2025-12-15 DOI: 10.1016/j.jseaes.2025.106915

Zhenmeng Sun , Xiangjie Cui , Xin Liu , Huan Liu , Xiancai Lu

The cation ordering mechanism and their influence on crystal structure evolution remain poorly understood. This study investigates the oscillatory zoned ferroan dolomite within moldic pores of micritic dolostone from the Ordovician Majiagou Formation in the eastern Ordos Basin, focusing on the site preference, distribution patterns of Fe in the dolomite structure, and its impact on the cation ordering process. Results show that from core to rim, the zoning exhibits increasing Fe content (0.27 mol%, 7.36 mol%, 10.55 mol%) with a corresponding decrease in Mg. Fe substitution primarily influences M–O bond lengths, leading to systematic changes in unit cell parameters: the a/b lattice parameters increase from 4.8066 Å to 4.8234 Å, the c lattice parameter from 16.0051 Å to 16.0690 Å, and the unit cell volume expands by approximately 1.1 %. Uniform strontium isotope compositions of the three zones indicate a homogeneous pore fluid derived from seawater. Further analysis via EXAFS spectroscopy, AC-TEM observation, and DFT calculations confirms that Fe²⁺ preferentially occupies Mg sites and tends to aggregate within Mg layers, forming nanoscale modulated structures and ordered domains. This causes local lattice distortion and defects, reducing the cation ordering degree from 0.45 to 0.30, while these regions may act as preferential sites for ordering progression. The study suggests that local migration and redistribution of trace elements in dolomite may facilitate structural ordering evolution. These findings provide a new crystal defect dynamics perspective for interpreting dolomite structural evolution, contributing to a better understanding of the “dolomite problem”.

阳离子的排序机制及其对晶体结构演化的影响尚不清楚。以鄂尔多斯盆地东部奥陶系马家沟组泥晶白云岩为研究对象，研究了白云岩结构中铁元素的位置偏好、分布规律及其对阳离子有序过程的影响。结果表明：从岩心到边缘，铁含量依次增加（0.27 mol%, 7.36 mol%, 10.55 mol%）， Mg含量相应降低；Fe取代主要影响M-O键长度，导致单元胞参数发生系统性变化：a/b晶格参数从4.8066 Å增加到4.8234 Å， c晶格参数从16.0051 Å增加到16.0690 Å，单元胞体积扩大了约1.1%。三个带的锶同位素组成均匀，表明孔隙流体来源于海水。通过EXAFS光谱、AC-TEM观察和DFT计算进一步分析证实，Fe2+优先占据Mg位点，并倾向于在Mg层内聚集，形成纳米级调制结构和有序畴。这导致了局部晶格畸变和缺陷，使阳离子有序度从0.45降低到0.30，而这些区域可能是有序进展的优先位点。研究表明，微量元素在白云岩中的局部迁移和再分配可能促进了构造的有序演化。这些发现为解释白云岩结构演化提供了新的晶体缺陷动力学视角，有助于更好地理解“白云岩问题”。

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引用次数: 0