Journal of Structural Geology最新文献

Spatial variation in topological characteristics of fault networks in rift basins: Zhu I Depression, Pearl River Mouth Basin, South China Sea 南海珠江口盆地朱一坳陷断网拓扑特征的空间变异

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-24 DOI: 10.1016/j.jsg.2026.105632

Guangrong Peng , Meng Zhang , Xiangtao Zhang , Hongbo Li , Zhe Wu , Chenxi Ma , Faru Liang , Zhiping Wu

Connectivity of two-dimensional fault networks documented with connecting nodes and branches shows spatial variation of Cenozoic fault networks in the Zhu I Depression, Pearl River Mouth Basin, South China Sea. Our data indicate that the fault network topology of the basement and syn-rift sequence is dominated by isolated nodes (I-nodes ≈ 80 %) and partly connecting branches (I–C branches ≈ 40 %). The connecting nodes and branches are primarily located at the depocentres and lateral surroundings of border faults of the half-grabens and grabens within the Zhu I Depression. In the post-rift fault networks, there is an increase in the proportion of isolated nodes (I-nodes ≈ 85 %) with the isolated branches (I–I branches ≈ 45 %) replacing partly connecting branches as the dominant branch type. The fault connections are concentrated in the locations of fault splays and relay-breaching along right-stepping en echelon fault sets. Due to the basin-scale sampling area with varying connectivity, the average number of connections per branch of the basement and syn-rift fault networks, both of which have undergone multi-phase extension, is close to that of the post-rift fault network, which has undergone single-phase extension. The location and size of the sampling area hinder the discrimination of the origins of fault networks through topological parameters. Intensified post-rift faulting that occurred at ∼16 Ma has led to an extra increase in the connectivity of the fault network at the upper post-rift sequence.

南海珠江口盆地朱一坳陷新生代断裂网络的空间变异特征显示了二维断裂网络节点和分支的连通性。数据表明，基底和同裂谷序列的断层网络拓扑结构以孤立节点（I-nodes≈80%）和部分连接分支（I-C分支≈40%）为主。连接节点和分支主要位于朱一坳陷内半地堑和地堑边界断裂的沉积中心和侧向周围。在裂后断层网络中，孤立节点（i -节点≈85%）的比例增加，孤立分支（I-I -分支≈45%）取代部分连接分支成为主导分支类型。断层连接主要集中在沿右行阶梯式断层集的断层展布和继电破坏位置。由于盆地尺度的采样区域连通性不同，基底和同裂谷断裂网络的分支平均连接数与裂谷后断裂网络的分支平均连接数接近，而基底和同裂谷断裂网络均经历了多相伸展。采样区域的位置和大小阻碍了通过拓扑参数识别故障网络的起源。在~ 16 Ma发生的裂谷后断裂加剧，导致裂谷后层序上部断层网络的连通性额外增加。

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引用次数: 0

Fault reactivation and tectonic conditions for unconformity-related uranium deposit: A paleostress approach (Athabasca Basin, Canada) 加拿大阿萨巴斯卡盆地不整合型铀矿床的断裂活化与构造条件

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-23 DOI: 10.1016/j.jsg.2026.105631

Manon Bulliard , Roger Soliva , Gaétan Milesi , Olivier Gerbeaud , Alexandre Laramas , Julien Mercadier

High-grade unconformity-related uranium (URU) deposits in the Athabasca Basin are spatially associated with graphitic-rich shear zones rooted in the basement and their propagation as brittle faulting and damage zones in the overlying sandstone. Investigating the tectonic phases associated with URU formation is particularly challenging due to its large polyphased history. This study is based on geological observations from 19 exploration drill cores in the Waterfound project (NE Athabasca Basin) and combines structural characterization with paleostress joint-inversions. Three main tectonic regimes were identified: (1) a pre-Athabasca Basin deposition NNE–SSW shortening affecting only the basement, (2) a syn-lithification NW–SE extension, and (3) a post-Athabasca NW–SE shortening. This polyphased tectonic history led to an increase in both the density and variety of fractures in the basin above a low-friction ENE–WSW graphitic shear zone in the basement. The extensional phase (2) developed with low horizontal differential stress, low fluid pressure and potentially relates to post-orogenic collapse or burial stress conditions only. The latest shortening stage (3), associated with uranium mineralization, locally reactivated a pre-existing fracture network in the sandstone and developed above an inherited ENE–WSW-trending graphitic shear zone in the basement. It requires tectonic stresses and fluid pressures estimated at 45–65 MPa to explain the observed structures. These results highlight the interplay between the mechanical strength of inherited structures, stress states, and fluid pressure in governing uranium-bearing fluid flow and provide new insights for Athabasca URU deposits exploration.

阿萨巴斯卡盆地高等级不整合相关铀矿床在空间上与根植于基底的富石墨剪切带及其在上覆砂岩中的脆性断裂和破坏带相关。研究与乌鲁地层相关的构造阶段尤其具有挑战性，因为它具有多阶段的历史。本研究基于Waterfound项目（东北阿萨巴斯卡盆地）19个勘探岩心的地质观测，结合构造表征和古应力联合反演。确定了3种主要的构造机制：(1)阿萨巴斯卡盆地前沉积NNE-SSW缩短仅影响基底；(2)同岩化作用NW-SE伸展；(3)阿萨巴斯卡盆地后NW-SE缩短。这种多期构造历史导致盆地内低摩擦ENE-WSW石墨剪切带之上的裂缝密度和种类均有所增加。伸展期(2)发育水平差应力低，流体压力低，可能仅与造山后塌陷或埋藏应力条件有关。最新的缩短阶段(3)与铀矿化有关，局部激活了砂岩中原有的裂缝网络，并在基底继承的ene - wsw向石墨剪切带之上发育。需要构造应力和流体压力估计在45-65兆帕来解释观测到的构造。这些结果突出了继承构造的机械强度、应力状态和流体压力在控制含铀流体流动中的相互作用，为阿萨巴斯卡URU矿床的勘探提供了新的见解。

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引用次数: 0

Microstructural, compositional and textural inheritance in deformed mafic amphibolites 变形基性角闪岩的显微结构、组成和结构继承

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-23 DOI: 10.1016/j.jsg.2026.105630

Laura Airaghi, Hugues Raimbourg, Jacques Précigout

This study investigates the scales of compositional equilibria and the role of early hydration for the development of microstructures and mineral fabrics in mafic amphibolites, all deformed along a major tectonic plate boundary (Hokkaido, Japan). From fractured domains to mm-size shear bands and meter-size shear zones, element and cathodoluminescence mapping, as well as thermodynamic modelling show that both in plagioclase and in amphibole, strong compositional gradients were observed at the smallest (10–200 μm) scale, which in many instances were inherited from an early, static stage of fracturing, hydration and replacement of igneous minerals. Phase distribution and grain sizes in shear bands and shear zones were also inherited from this early metamorphic stage, giving rise to: (1) monomineralic amphibole layers derived from amphiboles replacing aggregates of Fe-Mg igneous minerals in metagabbros, (2) monomineralic plagioclase layers derived from plagioclase-rich domains of metagabbros that experienced limited early breakdown reactions and (3) intimately mixed and fine-grained amphibole-plagioclase layers developed only where symplectites after igneous minerals were previously formed. While crystallographic and shape preferred orientations of amphibole were acquired from early fracture-driven reactions, and then strengthened in shear bands/zones by dissolution-precipitation, nucleation and oriented growth, the ones of plagioclase, whose reaction was incomplete in fractured domains, continued to evolve with increasing viscous strain and reaction progress. Where plagioclase experienced early, partial breakdown, viscous strain was further accommodated by dissolution-precipitation and phase nucleation. In contrast, where igneous plagioclase was largely preserved, crystal plastic deformation accompanied dissolution-precipitation. Heterogeneous early hydration of mafic rocks led therefore to a patchwork of local reacted domains, where inherited microstructures gave rise to heterogeneous phase distribution, grain sizes, fabrics and preconditioned the rock for strain partitioning, and hence, strain localization at a scale of hundreds of microns. In particular, phase mixing was the product not of strain, but rather of an initial stage of chemical reactions.

本研究探讨了基性角闪岩中成分平衡的尺度和早期水化作用对微结构和矿物组构发育的影响，这些角闪岩都是沿着一个主要构造板块边界（日本北海道）变形的。从断裂区域到毫米级剪切带和米级剪切带，元素和阴极发光图以及热力学模拟表明，在斜长石和角闪洞中，在最小（10-200 μm）尺度上观察到强烈的成分梯度，在许多情况下，这些梯度继承于早期的静态压裂、水化和火成岩矿物替代阶段。剪切带和剪切带的物相分布和晶粒尺寸也继承自这一早变质阶段，形成：(1)单矿物角闪石层由角闪石取代偏长岩中Fe-Mg火成岩矿物的聚集物形成；(2)单矿物斜长石层由富含斜长石的偏长岩域形成，经历了有限的早期破碎反应；(3)密切混合的细粒角闪石-斜长石层仅在火成岩矿物后的复晶岩形成的地方发育。角闪石的结晶学和形状择优取向是在早期断裂驱动反应中获得的，然后在剪切带/带中通过溶解-沉淀、成核和取向生长得到强化，而斜长石的结晶学和形状择优取向是随着断裂域中反应不完全的黏性应变的增加和反应的进行而继续演化的。当斜长石经历早期的部分击穿时，黏性应变进一步被溶解-析出和相成核所调节。而火成岩斜长石保存较多的地方，晶体塑性变形伴随溶蚀沉淀。因此，基性岩石的早期非均质水化导致局部反应域的拼凑，其中继承的微观结构产生了非均质相分布、晶粒尺寸、织构，并为岩石的应变分配提供了条件，因此，应变局部化在数百微米的尺度上。特别是，相混合不是应变的产物，而是化学反应初始阶段的产物。

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引用次数: 0

Three-dimensional bedrock implicit modeling and uncertainty quantification from sparse geological map data 稀疏地质图数据的三维基岩隐式建模与不确定性量化

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-21 DOI: 10.1016/j.jsg.2026.105627

Wei Lv, Xing Liu

Under conditions of data scarcity, traditional methods often struggle to construct reliable geological models. To maximize the utilization of information from limited data, this paper presents an implicit modeling method for shallow bedrock based on Generalized Radial Basis Function (GRBF) interpolation. Grounded in GRBF theory, the method extracts outcrop line data and geological attitude information from topographic and geological maps. These are then transformed into multiple interpolation constraints, including point, gradient, and tangential constraints, which are subsequently incorporated into a GRBF linear system to solve for the geological interfaces. The resulting surfaces are then processed according to established topological relationships and geological rules, forming solid models for visualization. Uncertainty is inherent in both the data and the process of three-dimensional (3D) modeling. As attitude information provides only an approximation of the normal vector, its associated uncertainty is significant. Therefore, this study primarily focuses on the uncertainty of attitude. A von Mises–Fisher (vMF) probability distribution model is defined for the normal vectors, and an ensemble of possible geological scenarios is generated through Monte Carlo sampling. This ensemble is used to construct multiple geological models, and the information entropy metric is then employed to quantitatively evaluate their quality and assess overall model uncertainty. The final uncertainty models provide effective decision support for engineering exploration, resource development, and disaster prevention and mitigation.

在数据稀缺的条件下，传统方法往往难以构建可靠的地质模型。为了最大限度地利用有限数据中的信息，提出了一种基于广义径向基函数（GRBF）插值的浅层基岩隐式建模方法。该方法以GRBF理论为基础，从地形图和地质图中提取露头线数据和地质姿态信息。然后将这些约束转换为多个插值约束，包括点约束、梯度约束和切向约束，然后将这些约束合并到GRBF线性系统中以求解地质界面。然后根据已建立的拓扑关系和地质规则对所得表面进行处理，形成用于可视化的实体模型。不确定性在数据和三维建模过程中都是固有的。由于姿态信息仅提供法向量的近似值，其相关的不确定性是显著的。因此，本研究主要关注态度的不确定性。定义了法向量的von Mises-Fisher （vMF）概率分布模型，并通过蒙特卡罗抽样生成了可能的地质情景集合。利用该集合构建多个地质模型，并利用信息熵度量定量评价模型质量，评估模型总体不确定性。最终的不确定性模型为工程勘探、资源开发和防灾减灾提供了有效的决策支持。

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引用次数: 0

Variscan superposition on ordovician extensional fault-related folds in the Eastern Pyrenees 东比利牛斯山奥陶系伸展性断裂相关褶皱上的瓦里斯坎叠加

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-20 DOI: 10.1016/j.jsg.2026.105629

Pablo Granado , Josep Maria Casas , Marco de Matteis , Òscar Gratacós

Our study investigates pre-Variscan Ordovician tectonics in the La Molina area (Eastern Pyrenees, Spain) by means of geological mapping and structural analysis of mesostructural data. We revisit the structural interpretation of pre-Upper Ordovician folds, revealing two mutually orthogonal, cleavage-free fold systems (WNW–ESE and NNE–SSW striking) affecting the Late Cambrian to Early Ordovician Serdinya Formation. These folds are interpreted as fault-related folds formed above steeply-dipping extensional faults during Mid Ordovician rifting. The geometry and orientation of Variscan mesostructures are shown to be strongly influenced by these earlier Ordovician folds, explaining the wide dispersion of fold axes and cleavage-bedding intersection lineations only found below the Upper Ordovician unconformity. The Upper Ordovician unconformity seals and locally erodes the limbs of those pre-existing folds. The hectometric to kilometric scale cleavage-free Ordovician folds contrast with the finer smaller-scale Variscan syn-foliar folds, and thus explains the absence of fold interference patterns. This work highlight that collecting and analysing detailed mesostructural data in orogenic hinterlands remains essential for interpreting regional tectonics, and it advances our understanding of the early tectonic evolution of the northern Gondwana margin.

本文通过地质填图和细构造资料的构造分析，对西班牙东比利牛斯山脉La Molina地区前瓦里斯坎奥陶系构造进行了研究。通过对上奥陶统前褶皱的构造解释，揭示了影响晚寒武世至早奥陶世Serdinya组的两个相互正交的无解理褶皱体系（WNW-ESE和NNE-SSW走向）。这些褶皱被解释为中奥陶世裂陷期间在陡倾伸展断裂上形成的断层相关褶皱。瓦里斯坎细观构造的几何形状和方向受到这些早奥陶世褶皱的强烈影响，这解释了褶皱轴和理理交错线的广泛分布，这些线只在上奥陶世不整合面下方发现。上奥陶统不整合封闭并局部侵蚀了原有褶皱的分支。奥陶纪的百米至千米尺度的无解理褶皱与较小尺度的瓦里斯坎同叶褶皱形成对比，从而解释了褶皱干涉模式的缺失。这项工作强调了在造山带腹地收集和分析详细的细观构造数据对于解释区域构造是至关重要的，它促进了我们对冈瓦纳北部边缘早期构造演化的理解。

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引用次数: 0

Origin, metamorphic remobilisation and structural control of the Buca della Vena orebody (Alpi Apuane, Italy) 意大利Alpi Apuane Buca della Vena矿体成因、变质再活化及构造控制

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-16 DOI: 10.1016/j.jsg.2026.105628

Simone Vezzoni , Diego Pieruccioni , Giancarlo Molli , Andrea Dini , Cristian Biagioni

Research on the ore-forming event(s) and their relationships with the Apennine deformation and metamorphism of the Alpi Apuane ore district (NW Tuscany, Italy) was abandoned with the closure of mining activities. The discovery of a remarkable thallium (Tl) anomaly associated with the pyrite ± baryte ± Fe-oxides ores has renewed scientific interest in this ore district during the last fifteen years. This work provides a detailed field and underground geological-structural investigation of one of these orebodies (previously exploited at the Buca della Vena mine), performed from cartographic to micro-scales, and integrated with available drill-log data, providing new insights into ore-forming events and late remobilisation during metamorphic processes. Our investigation suggests that the current ore settings were acquired during successive geological events related to a Permian hydrothermal-magmatic phase, and more recent Apennine-related deformations. The Permian hydrothermal activity related to the post-Variscan magmatic cycle produced the proto-ore associated with tourmalinisation and hydrothermal alteration halo in the Palaeozoic host-rock. The proto-ore was then partially exhumed, undergoing supergene alteration and minor syn-sedimentary Fe-oxide mineralisation during the upper Norian-Hettangian. Finally, the earlier hydrothermal and syn-sedimentary ores and the host rocks were involved in the Apennine orogenesis, suffering recrystallisation and partial remobilisation, acquiring their current mineralogical, textural, and structural settings.

随着采矿活动的停止，对意大利西北部托斯卡纳Alpi Apuane矿区的成矿事件及其与亚平宁变形变质作用关系的研究被放弃。在过去的15年中，与黄铁矿±重晶石±氧化铁矿石相关的铊（Tl）异常的发现重新引起了科学界的兴趣。这项工作对其中一个矿体（以前在Buca della Vena矿开采）进行了详细的现场和地下地质结构调查，从制图到微观尺度进行了研究，并与现有的钻井测井数据相结合，为变质过程中的成矿事件和晚期再活化提供了新的见解。我们的研究表明，目前的矿石背景是在与二叠纪热液-岩浆期相关的连续地质事件中获得的，以及最近与亚平宁岛相关的变形。与后瓦里斯坎岩浆旋回相关的二叠纪热液活动在古生代寄主岩中产生了与电气石化和热液蚀变晕相关的原矿石。原矿石部分出土，在上诺里安—鹤唐期经历了表生蚀变和少量同沉积铁氧化物矿化。最后，亚平宁造山过程中早期热液和同沉积矿石及寄主岩经历了重结晶和部分再活化作用，形成了现今的矿物学、构造和构造环境。

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引用次数: 0

Rift development at the Askja Fissure Swarm, Iceland 冰岛Askja裂缝群的裂谷发育

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-10 DOI: 10.1016/j.jsg.2026.105623

Fabio Luca Bonali , Martina Pedicini , Thomas R. Walter , Alessandro Tibaldi

Understanding how faulting and dyke intrusion interact to control rift development in volcanotectonic systems remains a key challenge, particularly in areas where multiple magma sources coexist. Here, we contribute to this topic by providing a high-resolution structural dataset for the Askja Fissure Swarm (AFS), one of the major rifts of the Northern Volcanic Zone of Iceland (NVZ), where central volcanoes and their associated dyke-fissure swarms act as magma plumbing systems and long-term eruption sources. We describe the Holocene structures of the AFS through the analysis of high-resolution remote sensing data and virtual field reconnaissance. We developed an inventory of 3749 individual structures, including dykes and fractures, mapped at a scale of 1:50,000, and systematically measured their strike, dip direction, length and kinematics. We recognized 395 eruptive fissures, 2301 extension dry fractures (fissures), and 1038 normal faults, of which 536 dip eastward and 502 westward. Along the main faults, we reconstructed the slip profiles, with the aim of evaluating the direction of along-axis fault and rift propagation. The overall dataset exhibits a predominant N–S to NNE–SSW strike, with an average strike of N17.5°E. Structure lengths vary from 10 m up to 13 km, with a mean of 445 m. Normal faults are generally longer than other structures, with a mean of 1042 m. With distance to the central volcanoes, we find the number of extension fractures and faults, their lengths and the slip profiles decrease. We interpret these characteristics as the effect of multiple dykes that laterally propagated outward from the magma chambers below Askja and Hrúthálsar central volcanoes. We also observed variation of fracture intensity and strike where the AFS intersects possibly hidden inherited transversal structures. Looking at the whole AFS, the tapering of fault slip profiles shows a dominant northward propagation of faults. This may indicate the superimposition of a regional northward propagation of the rift on the local effects of dykes and magma chambers, consistent with the northward spread of the NVZ.

了解断裂和岩脉侵入如何相互作用以控制火山构造系统中的裂谷发育仍然是一个关键的挑战，特别是在多个岩浆源共存的地区。在这里，我们通过为冰岛北部火山区（NVZ）的主要裂缝之一Askja裂缝群（AFS）提供高分辨率结构数据集来为这一主题做出贡献，其中中央火山及其相关的脉裂群充当岩浆管道系统和长期喷发源。通过对高分辨率遥感数据的分析和虚拟野外侦察，描述了AFS的全新世结构。我们编制了3749个独立构造的清单，包括堤防和裂缝，以1:5万的比例绘制，并系统地测量了它们的走向、倾斜方向、长度和运动学。发现喷发裂缝395条，伸展干裂缝2301条，正断层1038条，其中东倾536条，西倾502条。沿着主要断层重建了断层滑动剖面，目的是评估断层沿轴方向和裂谷的扩展。整个数据集以北南至北北-南南西走向为主，平均走向为N17.5°E。结构长度从10米到13公里不等，平均长度为445米。正断层一般比其他构造长，平均为1042米。随着离中心火山的距离增加，伸展断裂和断裂的数量、长度和滑动剖面减少。我们将这些特征解释为从Askja和Hrúthálsar中心火山下方的岩浆房向外横向传播的多个岩脉的影响。我们还观察到断裂强度和走向的变化，在AFS相交的地方可能隐藏着继承的横向构造。从整个AFS来看，断层滑动剖面的逐渐变细表明断层主要向北传播。这可能表明，裂谷的区域向北扩展叠加在岩脉和岩浆房的局部影响上，与NVZ向北扩展相一致。

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引用次数: 0

Extrusion of high-grade metamorphic and anatectic rocks during inclined transpression in the central Brasília Orogen, Western Gondwana 西冈瓦纳Brasília造山带中部斜挤压过程中高变质岩和无水岩的挤压作用

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-09 DOI: 10.1016/j.jsg.2026.105626

Fernando Resende Honorato , Marco Antônio Delinardo da Silva , Ticiano José Saraiva dos Santos , João Victor Oliveira Cunha , Ewerton Benetti Poloni , Pamela Pavanetto

Ancient and modern orogens are related to transpressional tectonics due to the Earth's spherical surface, often recording synchronous deformation, metamorphism, and anatexis. In the western Gondwana supercontinent, such relations are found in the Brasília Orogen, which formed from the collision between the Paranapanema, São Francisco-Congo, and Amazonian paleoplates during the Neoproterozoic Brasiliano/Pan-African Cycle. This study aims to investigate the deformational, metamorphic, and anatectic processes active in the central Brasília Orogen through field-based geological mapping and structural analysis, petrography, and U-Pb geochronology in zircon. The data show that the internal zone of the central Brasília Orogen underwent crustal shortening in the northeast-southwest direction, synchronous with lateral escape tectonics toward the southeast, suggesting an inclined transpressional context involving strain partitioning and the extrusion of deep-to-middle crustal rocks. The structural evolution was coeval with upper amphibolite to granulite facies metamorphism and anatexis, suggesting spatial and temporal relationships between structural fabrics, metamorphic and anatectic products. In this scenario, structures acted as primary controls of melt migration and granite emplacement, just as melt weakened the crust and facilitated structure nucleation. The Tonian (ca. 0.88 and 0.80 Ga) mafic protolith of the migmatitic orthogneiss and its leucosomes together with the migmatitic paragneiss and syntectonic granites confined the feedback loop between active ductile deformation, metamorphism and anatexis to the Cryogenian and Ediacaran periods (ca. 0.65 to 0.62 Ga), broadly constraining the interval of expressive crustal flow in the Brasilia Orogen.

由于地球是球形的，古代和现代造山带都与逆转构造有关，经常记录同步变形、变质作用和深熔作用。在冈瓦纳超大陆西部，这种关系在Brasília造山带中发现，该造山带是新元古代巴西利亚/泛非旋回期间由巴拉那帕内玛、弗朗西斯科-刚果古板块和亚马逊古板块碰撞形成的。本研究旨在通过野外地质填图、构造分析、岩石学、锆石U-Pb年代学等研究活动在Brasília造山带中部的变形、变质和析成岩过程。研究结果表明，Brasília造山带中部内带在东北—西南方向发生了地壳缩短，与东南方向的侧向逸出构造同步，表明该构造具有应变分区和深—中地壳挤压的斜转构造背景。构造演化与上部角闪岩-麻粒岩相变质和深熔作用同步，表明构造组构、变质和深熔产物之间存在时空关系。在这种情况下，构造是熔体迁移和花岗岩侵位的主要控制因素，就像熔体削弱地壳并促进构造成核一样。混合岩正长岩的东系（约0.88和0.80 Ga）基性原岩及其白色小体与混合岩副长岩和同构造花岗岩将活跃的韧性变形、变质作用和深熔作用的反馈回路限定在深冷系和埃迪卡拉系（约0.65 ~ 0.62 Ga），广泛地限制了巴西利亚造山带表现性地壳流动的间隔。

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引用次数: 0

Rethinking the crustal architecture of the Neoproterozoic gneiss domes in the Nubian Shield: Constraints from the Meatiq dome, Egypt 重新思考努比亚地盾新元古代片麻岩穹丘的地壳结构：来自埃及Meatiq穹丘的约束

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-03 DOI: 10.1016/j.jsg.2026.105615

Abdullah T. Mohammad , Yahia El Kazzaz

The Nubian Shield hosts amphibolite-grade, gneiss-cored domes surrounded by greenschist-grade island-arc and ophiolitic rocks. These domes record distinctly intense ductile deformation and higher metamorphism compared to adjacent rocks, yet their origin and geometry remain debated. Here we combine field observations, remote sensing, and structural–microstructural analyses to reassess the nature and architecture of these domes, focusing on the Meatiq dome in Central Eastern Desert of Egypt. Our results demonstrate that the dome represents a folded, thrust-related shear zone developed at mid-crustal levels within psammitic–pelitic metasediments overlain by ophiolitic and metavolcanic nappes. Microstructures record crystal-plastic deformation mechanisms at ∼670–450 °C with consistent top-to-NW shear indicators. Syn-kinematic emplacement of the Um Baanib and Abu Ziran granites occurred during NW-directed tectonic transport, with sub-magmatic microstructures recording the transition from magmatic to solid-state deformation. Both plutons display sheet-like geometries, controlled by lithological/rheological boundaries, and were later dissected by brittle thrust slices during doming. Although the Meatiq dome share some similarities with metamorphic core complexes, the absence of low-angle normal faults, rotational blocks, and migmatitic cores, combined with timing constraints, rules out core complex or diapiric origin. Instead, we argue that its domal geometry reflects thrust-related folding and multi-phase deformation associated with NW-directed tectonic transport during the East and West Gondwanaland collision (∼605–596 Ma), later modified by multiple Phanerozoic rifting phases. This evolutionary model highlights thrust-related tectonics as the primary driver of the Meatiq dome and prompts a reassessment of similar domes in the Nubian Shield. In addition, the results have broader implications for understanding gneiss-cored domes in orogenic belts worldwide and dynamic feedback between deformation and magmatism at mid-crustal shear zones.

努比亚地盾拥有角闪岩级、片麻岩芯的圆顶，周围环绕着绿片岩级岛弧和蛇绿岩。与邻近的岩石相比，这些圆顶记录了明显强烈的韧性变形和较高的变质作用，但它们的起源和几何形状仍有争议。在这里，我们结合实地观察、遥感和结构-微观结构分析来重新评估这些圆顶的性质和结构，重点是埃及中东部沙漠的Meatiq圆顶。我们的研究结果表明，在蛇绿岩和变质火山推覆体覆盖的泥质-泥质变质沉积层中，丘顶是一个褶皱的、逆冲相关的剪切带。显微结构记录了在~ 670-450°C的晶体塑性变形机制，具有一致的顶部到nw剪切指标。乌姆巴尼布和阿布兹兰花岗岩的同步运动学侵位发生在北西向构造搬运过程中，次岩浆微结构记录了岩浆向固态变形的过渡。这两个岩体都显示出薄片状的几何形状，受岩性/流变边界的控制，后来在穹隆过程中被脆性逆冲切片解剖。尽管Meatiq圆顶与变质核杂岩有一些相似之处，但由于缺乏低角度正断层、旋转块体和混染岩心，结合时间限制，排除了核杂岩或底辟成因的可能性。相反，我们认为其隆起的几何形状反映了东、西Gondwanaland碰撞（~ 605-596 Ma）期间与北西向构造运输有关的逆冲相关的褶皱和多期变形，后来被多个显生宙裂陷期所修正。这一演化模型强调了与逆冲相关的构造是Meatiq穹窿的主要驱动力，并促使人们重新评估努比亚地盾中类似的穹窿。此外，研究结果对于认识世界范围内造山带的片麻岩核圆顶以及中地壳剪切带变形与岩浆活动的动态反馈具有更广泛的意义。

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引用次数: 0

Slab kinematics and strain localization in NE China: Polyphase deformation of the Hulin Complex during Late Mesozoic subduction 中国东北板块运动与应变局部化：晚中生代俯冲期间虎林杂岩的多期变形

IF 2.9 2区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Structural Geology

Pub Date : 2026-01-02 DOI: 10.1016/j.jsg.2025.105614

Wei Pi , Han Zheng , Jian Zhang , Zhiyuan He , Johan De Grave , Ian P. Cawood , Yong Liang , Heng Peng , Guochun Zhao

Crustal shear zones in Northeast China preserve a critical record of Paleo-Pacific subduction, yet distinguishing the superimposed tectonic fabrics remains a challenge. We resolved this by reconstructing the structural and thermal history of the Hulin Complex, linking local deformation directly to specific slab dynamics. During the Late Jurassic to Early Cretaceous (D₁: ca. 160–130 Ma), a moderate oblique subduction angle (∼30–40°) drove NE–SW sinistral transpression. This phase produced distributed general shear (Flinn's k = 0.73–0.91; W_k = 0.64–0.67) under mid-crustal conditions (∼350–500 °C), accommodated by quartz rhomb <a> and prism <a> slip at differential stresses of 15–18 MPa. In the Cretaceous (D₂: ca. 130–85 Ma), accelerated SE-directed slab rollback stretched the lithosphere, triggering regional extension (Flinn's k = 0.85–1.01; W_k = 0.57–0.62). Strain localized into weak, mica-rich zones (>15 vol%) as differential stresses dropped to 13–14 MPa and temperatures cooled to 300–400 °C. This extension facilitated synchronous magmatism. By the Late Cretaceous (D₃: ca. 85–68 Ma), a shift to W–NW subduction created a lower obliquity angle (∼20–30°). This renewed dextral transpression reactivated older structures in the mid-to-lower crust (≤300–400 °C) but at significantly higher stresses (21–34 MPa). Quartz fabrics shifted to basal <a> slip, reflecting strain repartitioning (Flinn's k = 0.63–0.76; W_k = 0.67–0.71). Our findings demonstrate that shear zone evolution is governed by specific subduction parameters: (1) shallower slab dips enhance coupling to localize strain; (2) rapid rollback weakens the lithosphere to drive extension; and (3) high convergence obliquity (angles <30°) amplifies the simple shear component. Thus, the Hulin Complex acts as a sensitive rheological recorder, capturing the changing tempo and geometry of the subducting slab.

中国东北的地壳剪切带保存了古太平洋俯冲的重要记录，但区分叠合构造仍然是一个挑战。我们通过重建虎林杂岩的结构和热历史来解决这个问题，将局部变形直接与特定的板动力联系起来。晚侏罗世至早白垩世（D1：约160 ~ 130 Ma），一个中等斜向俯冲角（~ 30 ~ 40°）驱动了NE-SW左旋转动。该相在中地壳条件下（~ 350 ~ 500°C）产生了分布的总剪切（Flinn’s k = 0.73-0.91; Wk = 0.64-0.67），在15 ~ 18 MPa的差应力下，由石英菱形和棱形滑移（<a>；和棱镜<；a>；滑移）所适应。在白垩纪（D2：约130 ~ 85 Ma），加速的东南向板块回滚拉伸了岩石圈，引发了区域伸展（Flinn’s k = 0.85 ~ 1.01; Wk = 0.57 ~ 0.62）。当差应力降至13-14 MPa，温度降至300-400°C时，应变局部定位到弱的富云母区（>15 vol%）。这种扩展促进了同步岩浆活动。到晚白垩世（D3：约85-68 Ma），向W-NW俯冲的转变产生了较低的倾角（~ 20-30°）。这种更新的右旋转活动重新激活了中下地壳（≤300-400°C）的旧构造，但在明显更高的应力下（21-34 MPa）。石英织物向基底滑动，反映应变重新分配（Flinn’s k = 0.63-0.76; Wk = 0.67-0.71）。研究结果表明，剪切带的演化受特定俯冲参数的控制：(1)较浅的板块倾角增强了局部应变的耦合；(2)快速回滚削弱岩石圈，推动伸展；(3)高辐合倾角（角<；30°）放大了简单剪切分量。因此，虎林杂岩充当了一个敏感的流变记录仪，捕捉俯冲板块的变化速度和几何形状。

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引用次数: 0