In March 2024, Wugongshan in Jiangxi Province, China, officially joined the UNESCO Global Geoparks Network. Wugongshan Geopark is renowned for its rich geological heritage, particularly its massive and well-preserved Mesozoic granite dome. The geological evolution of this granite dome has controlled the formation and vertical distribution of various types of landscapes within the geopark. The diverse sites of geological interest and landscapes, along with the granite dome, collectively constitute a unique whole, a characteristic that is rare among global geoparks. Therefore, the geological heritage of Wugongshan Geopark holds significant research value and international significance. In this paper, we provide a detailed introduction to the diversity of geological, geomorphological, and hydrological characteristics and processes of Wugongshan Geopark, analyzing the kinematic polarity of granite dome from a structural deformation perspective and comparing the evolution of granite domes with similar features in other global geoparks. Our findings reveal that the abundant geological and geomorphological resources of Wugongshan Geopark not only serve as a natural laboratory for scientific research but also lay a solid foundation for promoting popularization of geosciences.

The late Palaeozoic tectonic magmatism in the northern Qaidam tectonic belt (NQTB) related to the PalaeoTethys Ocean has become a critical issue. We performed a detailed geochronological and geochemical study of Lenghu (LH) granitic rocks in the western NQTB. LA-ICP-MS U-Pb dating of zircons from LH granitic rocks yields emplacement ages of 253 +/- 4 Ma and 264 +/- 4 Ma, indicating a two-stage emplacement process. Geochemical analyses show that the LH granitic rocks have low ACNK values and are enriched in LILEs (Rb, Th, Ba) and depleted in HFSEs (Sr, Nd, and Ta). The samples are enriched in LREEs (LREE/HREE=1.5-7.3). Values of (La/Yb)N range between 0.9 and 6.5, and all samples show negative Eu anomalies (delta Eu=0.2-0.6), with typical characteristics of island arc magmatism. The LHgranitic rocks have epsilon Hf(t) values of-3.7 to +8.0 and yield a TCDMage of1.51-0.78 Ga. The data suggest that the LHgranitic rocks were derived from partial melting of Proterozoic crust-related mafic to intermediate rocks with significant crust-mantle interactions. The results, combined with regional magmatic information, indicate that the Late Permian-early Triassic magmatism in western NQTB were controlled by subduction rollback-retraction of South Kunlun Oceanic plate under the Kunlun-Qaidam Block.

Fractal analysis was used to characterize the organic matter nanopore structure in tectonically deformed shales, providing insights into the heterogeneity and complexity of the pore network. Shale samples from different tectonic deformation styles (undeformed, brittle deformed, and ductile deformed) in the Lower Cambrian Niutitang Formation in western Hunan, South China, were collected. By comprehensively applying techniques such as low-temperature gaseous (CO2 and N2) adsorption (LTGA), scanning electron microscopy (SEM), and ImageJ analysis, we accurately obtained key parameters of the pore structure. The results show ductile deformation reduces fractal dimension (DM) by ~0.2 compared to brittle deformed shale, reflecting the homogenization of organic nanopore structures. Brittle deformation leads to a more complex pore network, while ductile deformation reduces the complexity of the organic nanopore structure. The fractal dimensions are affected by various factors, with micropore development being crucial for undeformed shale, clay and pore length–width ratio dominating in brittle deformed shale, and all-scale pores being key for ductile deformed shale. This study provides the first comparative analysis of fractal dimensions across undeformed, brittle deformed, and ductile deformed shales, revealing distinct pore structure modifications linked to deformation styles. These findings not only enhance our understanding of the influence mechanism of tectonic deformation on shale pore structure and fractal characteristics but also provide a theoretical basis for optimizing shale gas exploration and production strategies. These findings offer a framework for predicting gas storage and flow dynamics in tectonically complex shale reservoirs. For instance, in areas with different tectonic deformation styles, we can better evaluate the gas storage capacity and production potential of shale reservoirs according to the obtained fractal characteristics, which is of great significance for efficient shale gas development.

The ductile shear deformation of Precambrian basement rocks in Wuyishan provides a crucial perspective on intraplate orogeny in the South China Block (SCB). This study focuses on the Longquan‐Badu ductile shear zone in southeastern Zhejiang, employing field observations, thin section analysis, quartz electron backscatter diffraction (EBSD), zircon U–Pb dating and 40Ar/39Ar geochronology. Two distinct phases of deformation, referred to as D1 and D2, have been identified. D1 is primarily characterized by a WNW–ESE striking foliation within a NE‐plunging lineation, indicating top‐to‐SSW shearing. The paragneiss within the Badu complex that experienced D1 deformation has been dated to 247–239 Ma through zircon U–Pb analysis, corresponding to the prevalent high‐pressure metamorphic age in the region. This correlation suggests that the D1 deformation event coincided with crustal thickening during the Early Triassic. D2 deformation exhibits folds, foliation, S‐C fabrics and mylonitic microstructures and is mainly characterized by striking NNE–SSW with steeply dip, demonstrating a dominant dextral strike–slip component. Quartz c‐axis orientations in mylonitic rocks indicate deformation temperatures between 350°C and 550°C with asymmetric girdle patterns suggesting simultaneous basal and prism slip. The plateau ages of muscovite from mylonitic rocks obtained through 40Ar/39Ar dating are approximately ~228 Ma implying that the D2 deformation occurred under retrograde amphibolite to greenschist facies metamorphic conditions during Middle Triassic. Collectively these data along with regional geological evidence signify two distinct intracontinental orogenic processes occurring in eastern SCB. Considering Early Mesozoic tectonothermal events in Cathaysia Block, it can be inferred that intraplate orogeny in Wuyishan resulted from plate‐margin collisions between SCB and peripheral plates following scissors closure of Palaeo‐Tethys from east to west.

[Objective]The northern margin tectonic zone of the Qaidam Basin underwent a transition from oceanic subduction to continental subduction during the Early Paleozoic,resulting in the formation of the ultrahigh-pressure metamorphic zone known as the northern Qaidam tectonic zone(NQTZ).There has been a longstanding debate regarding the collapse time of the NQTZ.The Maoniushan Formation has long been regarded as a sign of the end of orogeny;however,recent studies show that the Maoniushan Formation has spanned a long time,and it is controversial when the orogenic belt began to collapse.This study aims to determine the age and genetic background of the Maoniushan Formation and to understand the tectonic transition process of the northern Qinghai-Tibet Plateau from the Proto-Tethys to the Paleo-Tethys.[Methods]Deep-earth samples,including volcanic and intrusive rocks,offer valuable insights into the activity of the crust during this period.In order to investigate the volcaniclastic rocks and granites in the Gahai-Nanshan area,located in the eastern section of the NQTZ,zircon LA-ICP-MS U-Pb chronology and Lu-Hf isotope methods were employed to explore the formation age of igneous rocks and the characteristics of source rocks.[Results]The zircon U-Pb chronology reveals that the volcaniclastic rocks of the Maoniushan Formation originated approximately 423 Ma.Furthermore,the intrusive granite was formed at 370 Ma,indicating that the volcanic eruption occurred during the Late Silurian,while the subsequent intrusion and crystallization of the granites occurred during the Late Devonian.The zircon Lu-Hf isotope data reveals that the εHf(t)values of the Late Silurian tuffs are concentrated within the range of-11.5 to-8.3,and the corresponding two-stage Hf model ages are primarily between 1945-2133 Ma.These results indicate that the volcanic rocks predominantly originated from partially melting ancient crustal materials.In contrast,the εHf(t)values of the Late Devonian intrusive granites exhibit a distribution within the range of 3.9-9.1,accompanied by two-stage Hf model ages primarily falling within the 792-1118 Ma range.The results suggest that the granites mainly resulted from partially melting Meso-Neoproterozoic crustal materials.Based on a comprehensive analysis of regional geological and petrological data,it is postulated that the Late Silurian-Early Devonian witnessed pronounced orogenesis resulting from continental deep subduction.This event led to substantial crustal thickening in the NQTZ,where the thickened crustal basement of the Oulongbruk experienced partial melting,ultimately giving rise to the volcanic rocks observed during this period.During the Late Devonian,delamination of the thickened crust facilitated the upwelling of the asthenosphere mantle,triggering regional crustal extension.The interaction between mantle material and crust results in the formation of granitic-volcanic rocks.[Conclusion]The Maoniushan Formation in the region encapsulates a significant period,making it unsuitable to represent the end of orogeny.Late Devonian igneous rocks indicate that the NQTZ entered a period of substantial crustal extension during this time.[Significance]The late Devonian igneous rocks of Maoniushan Formation regionally mark the end of orogeny and the beginning of the Paleo-Tethys tectonic domain.

The ductile shear zones within the North Wuyishan domain are key to understand the tectonic evolution of the South China Block (SCB). This study integrates a multifaceted approach, including field observations, thin section analysis, quartz electron backscatter diffraction (EBSD), zircon U-Pb dating, and mica Ar-40/Ar-39 dating, to elucidate the deformation history of these shear zones in North Wuyishan. The research identifies a two-stage deformation process of early Paleozoic. The initial D1 phase is marked by a top-to-SW thrusting shear, with associated felsic veins dated to the Ordovician period (447 +/- 10 Ma to 459 +/- 4 Ma), correlating with high-grade metamorphism and partial melting. The later D2 phase is characterized by NE-striking foliation and lineation, indicative of sinistral strike-slip shear, dated to the early Devonian (412 Ma) and early Carboniferous (similar to 354 Ma). The D1 phase suggests early crustal thickening and melting within the Cathaysia block, while D2 indicates a transpressional regime during post-orogenic adjustment. The geological features of the SCB, notably the absence of arc magmatism, ophiolitic m & eacute;lange, and high-pressure metamorphism, comply with an intracontinental rift closure model as previously proposed. This model supports the hypothesis that the Early Paleozoic intracontinental orogeny in the SCB was likely a far-field consequence of a continental collision between the SCB-North Vietnam and South Vietnam blocks near the east Gondwana supercontinent.

Introduction to Global Tectonic Systems, pp. 183-231 (2024) No AccessChapter 7: Epsilon-Shaped Tectonic SystemsYuzhu Kang, Shuwen Xing, Zhihong Kang, Yinsheng Ma, Dewu Qiao, Zongxiu Wang, and Zhihu LingYuzhu KangSinopec Petroleum Exploration and Production Research Institute, China Petrochemical Corporation, Beijing, China, Shuwen XingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhihong KangChina University of Geosciences (Beijing), Beijing, China, Yinsheng MaInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Dewu QiaoInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zongxiu WangInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, and Zhihu LingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, Chinahttps://doi.org/10.1142/9789811285561_0007Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: In this chapter, epsilon-shaped tectonic systems are introduced, including those in China, Eurasia, Irkutsk in southern Siberia of Russia, Teli in Turkey, Gadomein France, England, North America, Cincinnati in southern North America and Brazil in South America. Keywords: Tectonic systemEpsilon-shapedType FiguresReferencesRelatedDetails Recommended Introduction to Global Tectonic SystemsMetrics History KeywordsTectonic systemEpsilon-shapedTypePDF download

The South China region has undergone a complex tectonic history since the Mesozoic era, characterized by significant tectonic regime transformations. However, the mechanism behind these transformations is still subject to debate. This study aims to elucidate the specific manifestations and stress mechanisms driving the tectonic transformations and their geological background. Through field geological surveys, effective stress inversions and analysis of lithofacies palaeogeography in Fujian Province, we have identified six distinct tectonic episodes that occurred during the Mesozoic: (a) late Middle Triassic to early Late Triassic: intense NNE–SSW compression generated an unconformity between the An'ren Formation and Dakeng Formation; (b) middle Late Triassic to early Middle Jurassic: NNE–SSW extension exerted control over the deposition of the Dakeng Formation, Wenbinshan Formation and Zhangping Formation; (c) late Middle Jurassic to early Late Jurassic: NW–SE compression resulted in an unconformity between the Zhangping Formation and Changlin Formation; (d) late Jurassic to early Cretaceous: NW–SE extension influenced the deposition of the Changlin Formation, Nanyuan Formation and Xiaoxi Formation; (e) late Early Cretaceous to Late Cretaceous: a strike–slip stress field caused an unconformity between the Xiaoxi Formation and Shaxian Formation; (f) post‐Late Cretaceous: NE–SW extension occurred. During the late Middle Jurassic to early Late Jurassic period, there was a notable change in the distribution of lithofacies palaeogeography. The coexistence of NE and E‐W‐trending patterns shifted to a predominant NE‐trending pattern, which was controlled by the palaeostress field transitioning from NNE–SSW extension to NW–SE compression. These changes indicate a tectonic regime transformation in Southeast China during this period. Considering the sedimentary, magmatic and tectonic activities, the tectonic evolution of Southeast China was predominantly influenced by the Palaeo‐Tethys tectonic domain from the Early Triassic to early Middle Jurassic and by the Palaeo‐Pacific tectonic domain from the late Middle Jurassic to the Cretaceous.

Introduction to Global Tectonic Systems, pp. 117-145 (2024) No AccessChapter 5: N-N-E-Trending Tectonic SystemsYuzhu Kang, Shuwen Xing, Zhihong Kang, Yue Zhao, Zhihu Ling, Zhijiang Kang, and Huijun LiYuzhu KangSinopec Petroleum Exploration and Production Research Institute, China Petrochemical Corporation, Beijing, China, Shuwen XingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhihong KangChina University of Geosciences (Beijing), Beijing, China, Yue ZhaoInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhihu LingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhijiang KangSinopec Petroleum Exploration and Production Research Institute, Beijing, China, and Huijun LiInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, Chinahttps://doi.org/10.1142/9789811285561_0005Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: In this chapter, N-N-E-trending tectonic systems are introduced, including those in China, New Zealand–Tonga, the Eastern United States and the east coast of South America. Keywords: Tectonic systemN-N-E-trendingType FiguresReferencesRelatedDetails Recommended Introduction to Global Tectonic SystemsMetrics History KeywordsTectonic systemN-N-E-trendingTypePDF download

Introduction to Global Tectonic Systems, pp. 21-50 (2024) No AccessChapter 2: E-W-Trending Tectonic SystemsYuzhu Kang, Shuwen Xing, Yue Zhao, Yinsheng Ma, and Zongxiu WangYuzhu KangSinopec Petroleum Exploration and Production Research Institute, China Petrochemical Corporation, Beijing, China, Shuwen XingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Yue ZhaoInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Yinsheng MaInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, and Zongxiu WangInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, Chinahttps://doi.org/10.1142/9789811285561_0002Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: In this chapter, E-W-trending tectonic systems are introduced, including those in the Arctic region, China, the Northern Hemisphere and the Southern Hemisphere. Keywords: Tectonic systemE-W-trendingType FiguresReferencesRelatedDetails Recommended Introduction to Global Tectonic SystemsMetrics History KeywordsTectonic systemE-W-trendingTypePDF download

Introduction to Global Tectonic Systems, pp. 233-259 (2024) No AccessChapter 8: S-Shaped or Reverse S-Shaped Tectonic SystemsYuzhu Kang, Shuwen Xing, Zongxiu Wang, Zhihong Kang, Yinsheng Ma, Zhijiang Kang, and Zhihu LingYuzhu KangSinopec Petroleum Exploration and Production Research Institute, China Petrochemical Corporation, Beijing, China, Shuwen XingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zongxiu WangInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhihong KangChina University of Geosciences (Beijing), Beijing, China, Yinsheng MaInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhijiang KangSinopec Petroleum Exploration and Production Research Institute, Beijing, China, and Zhihu LingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, Chinahttps://doi.org/10.1142/9789811285561_0008Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: In this chapter, S-shaped or reverse S-shaped tectonic systems are introduced, including reverse S-shaped systems in Qinghai–Tibet–Burma, China, the western coast of North America and S-shaped systems in western South America and western Africa. Keywords: Tectonic systemS-shapedReverse S-shapedType FiguresReferencesRelatedDetails Recommended Introduction to Global Tectonic SystemsMetrics History KeywordsTectonic systemS-shapedReverse S-shapedTypePDF download

Introduction to Global Tectonic Systems, pp. 281-295 (2024) No AccessChapter 10: Evolutionary Features and Compound Relationships of Tectonic SystemsYuzhu Kang, Shuwen Xing, Zongxiu Wang, Zhihong Kang, Yinsheng Ma, Zhijiang Kang, and Zhihu LingYuzhu KangSinopec Petroleum Exploration and Production Research Institute, China Petrochemical Corporation, Beijing, China, Shuwen XingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zongxiu WangInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhihong KangChina University of Geosciences (Beijing), Beijing, China, Yinsheng MaInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhijiang KangSinopec Petroleum Exploration and Production Research Institute, Beijing, China, and Zhihu LingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, Chinahttps://doi.org/10.1142/9789811285561_0010Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: In this chapter, the evolutionary features and compound relationships of tectonic systems are introduced. Five evolutionary features are proposed as follows: phase, inheritance, migration, difference and conversion, showing the complexity of all tectonic systems. The genetic evolution of various blocks is controlled by tectonic systems, while the formation and evolution of tectonic systems are controlled and affected by various blocks. Their interactions have created the current global tectonic pattern and land–sea changes and evolution. Keywords: Tectonic systemEvolutionCompound FiguresReferencesRelatedDetails Recommended Introduction to Global Tectonic SystemsMetrics History KeywordsTectonic systemEvolutionCompoundPDF download

Introduction to Global Tectonic Systems, pp. 261-280 (2024) No AccessChapter 9: Rotation-Torsional Tectonic SystemsYuzhu Kang, Shuwen Xing, Zongxiu Wang, Zhihong Kang, Yinsheng Ma, Zhijiang Kang, and Zhihu LingYuzhu KangSinopec Petroleum Exploration and Production Research Institute, China Petrochemical Corporation, Beijing, China, Shuwen XingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zongxiu WangInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhihong KangChina University of Geosciences (Beijing), Beijing, China, Yinsheng MaInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, Zhijiang KangSinopec Petroleum Exploration and Production Research Institute, Beijing, China, and Zhihu LingInstitute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, Chinahttps://doi.org/10.1142/9789811285561_0009Cited by:0 (Source: Crossref) PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail Abstract: In this chapter, rotation-torsional tectonic systems are introduced, including the rotation-torsional systems in China, the northern Sakhalin geese-shaped systems in northeastern Russia, the broom-shaped systems in the western Indian Ocean and southwestern Pacific, the double-ring compound rotation-torsional systems in Antarctica and the concentric radial systems in the Arctic. Keywords: Tectonic systemRotation-torsionalType FiguresReferencesRelatedDetails Recommended Introduction to Global Tectonic SystemsMetrics History KeywordsTectonic systemRotation-torsionalTypePDF download

Key information on sedimentary or tectonic events is recorded in deformation structures formed in unlithified and lithified sediments. Disputes about the classification and identification of the two types of deformation have become increasingly relevant. The present study systematically summarizes, based on consolidation states, the genetic mechanisms of deformation. Consolidation conditions may affect deformation patterns and morphology; this can be a clue to distinguish soft-sediment deformation from tectonic deformation. Liquefaction is a typical state of unconsolidated sediment and can create clastic dikes, liquefied breccia, convolute laminae, load cast, and water-escape structures. Synsedimentary faults may be formed in weakly consolidated sediments. Most deformation structures of lithified sediments are large-scale folds and faults, but small-scale structures – especially microfolds – are difficult to distinguish from slump folds. Tectonic folds can be formed in different strata and induced by tectonic events; they differ from slump folds in morphology, distribution, and related structures. We demonstrated that consideration of liquefaction, folds in different strata – matched with the regional geological regime, related deformation structures, and micro-deformation structures – can be clues to the identification of deformation origins.

Based on the study of gold field structure in Jiaodong area, a new model is put forward which developed as “magma core complex uplift-detachment zone structure” links detachment zone structure and magmatic core complex, and metamorphic core complex structure was not developed in the Mesozoic area.In this study, after more than 10 years of tectonic deformation and alteration lithofacies mapping, magmatic structure mapping, paleomagnetic research and kinematic survey, combined with geophysical data analysis, it is found that the typical “Linglong magmatic core complex uplift and detachment zone structure” in Jiaodong area shows a long-round arch dome.The geological phenomena show:（1）The dome core is composed of multi-stage and multi-structural granitic complexes;（2）The granitic complex is trapped by faults, and these detachment zones and shovel type fractures with low and middle-angles are shear fractured.The broad fracture zones show superposition of ductile and brittle deformation and post-magmatic hydrothermal metasomatic alteration mineralization;（3）The hanging wall rocks of the detachment fault are distributed around the magmatic core, and are composed of basement metamorphic rocks and Mesozoic sedimentary rocks, showing a state of detachment depression.The “magmatic core complex uplift-detachment zone structure” is a new model conforming to the East Asian intracontinental tectono-magmatic activation background.Through the study of magma core complex uplift-detachment zone structure, it is proposed that magmatic uplift and pull-apart basin belong to the same tectonic system, extruding tectonic-magmatic uplift and extensional detachment depressions are the products of stress field transformation process, and disintegrating shovel fault and brittle ductile superposition tectonic-rock belt are the targets of metallogenic prediction.Regional diagenetic and metallogenic laws are taken as the mark of direct observation and exploration, and regional geological and metallogenic laws are studied.Geological survey and metallogenic prediction have extensive popularization value and demonstration significance.

The South China Block (SCB) experienced multi-stage tectono-magmatic events during the Mesozoic, forming a broad and episodic intracontinental orogenic belt. It is controversial whether the driving force of the Mesozoic intracontinental orogeny in the SCB is related to the far-field effects of plate convergence. To better understand the driving mechanism of intracontinental orogeny, we conducted a detailed structural investigation of the Xingguo area in southern Jiangxi Province, located in the central part of the SCB. Two regional-scale buckling superposed folds were identified as the Chayuan arcuate syncline of the fold axis protruding to the north (Type 2a interference pattern) and the Xiefang syncline of the fold axis extending NW–SE (Type 1d interference pattern). Although there are differences in fold interference patterns, the Chayuan arcuate syncline and Xiefang syncline were formed by the superimposition of the Middle–Late Triassic NE–SW shortening and the Middle–Late Jurassic nearly E–W shortening. This phenomenon of the differential fold interference patterns in the same tectonic setting is determined by the difference in geometric characteristics of their initial folds. Combined with the variation of the Mesozoic paleostress field, it is considered that the Mesozoic intracontinental orogeny in the SCB is mainly controlled by the far-field stress propagation generated by plate interactions. Based on the analysis of tectonic architecture, we propose that the Mesozoic tectonic evolution of the SCB experienced a transformation from multi-plate convergence in the Triassic to Andean-type subduction in the Jurassic. This tectonic transformation finally resulted in the reactivation of the Precambrian multi-terrane collage of the SCB.

The Early Paleozoic tectono-thermal event was a significant orogenic activity during the Phanerozoic era,which had a profound impact on the early crust of the South China Block（SCB） and established the foundation for later tectonic activity.The Wuyi-Yunkai orogenic belt in Southeastern China was extensively exposed to Early Paleozoic magmatism,the genetic mechanism of which remains controversial.To shed light on this issue,detailed petrological,geochemical,and zircon U-Pb-Hf isotopic studies were carried out on two granitoids,namely the Yuntongshan pluton and the Gaoqiao pluton,identified in the central Wuyishan.Zircon U-Pb chronology of the Yuntongshan and Gaoqiao bodies yielded ages of437±4 Ma（MSWD=2.2） and 404±2 Ma（MSWD=12）,respectively,indicating that they were emplaced during the Early Silurian and Early Devonian periods.These granitoids are primarily composed of biotite-granite and biotite-monzonitic-granites,with high concentrations of SiO2（73.59-75.91 wt%）,K2O+Na2O（8.31-8.73wt%）,and low contents of MgO,CaO,Cr,Ni.They are classified as high-K calc-alkaline and weakly metaluminous-strongly peraluminous S-type granites.These granitoids are enriched in light rare earth elements（LREEs） and large ion lithophile elements（LILEs） and depleted in heavy rare earth elements（HREEs） and high field strength elements（HFSEs） with arc affinity.The εHf（t） values of-3.3 to-15.4 with two-stage Hf model ages ranging from 2829 to 1644 Ma,combined with the presence of Neoproterozoic inherited zircons,suggest that the primary magma of these granitoids was derived from the partial melting of Neoproterozoic crust with a Paleoproterozoic crustal model age.These findings,combined with the spatio-temporal distribution of regional magmatism,reveal that the late Early-Paleozoic granitoids formed in the intraplate orogenic background originating from the subduction of the proto-Tethys Ocean and proto-Pacific Ocean around the margin of the east Gondwana supercontinent.

Abstract Occurring after the early Palaeozoic collisional orogeny and continental deep subduction, late Palaeozoic tectonic magmatism in the northern Qaidam Tectonic Belt (NQTB) related to the Palaeo-Tethys Ocean has become a critical issue. We performed a detailed geochronological and geochemical study of Lenghu (LH) granitic rocks in the western NQTB to obtain better constraints on the subduction processes of the Palaeo-Tethys Ocean in the northern Qinghai–Tibetan Plateau. LA–ICP–MS U–Pb dating of zircons from LH granitic rocks in the western NQTB yields emplacement ages of 253 ± 4 Ma and 264 ± 4 Ma, indicating a two-stage emplacement process. Geochemical analyses show that both the late Permian and Early Triassic granitic rocks have low A/CNK and A/NK values and are enriched in LILEs (Rb, Th, Ba, Zr, and Hf) and depleted in HFSEs (Sr, P, Ti, Nd, and Ta). The SREE contents range from 36 to 189 ppm, and the samples are enriched in LREEs (LREE/HREE =1.5–7.3). Values of (La/Yb)N range between 0.9 and 6.5, and all samples show negative Eu anomalies (δEu =0.2–0.6), with typical characteristics of island arc magmatism. The two-stage granitic rocks have εHf(t) values of -3.7 to +8.0 and yield a two-stage depleted mantle Hf model age of 1.51-0.78 Ga. The data suggest that the late Permian–Early Triassic granitic rocks were derived from partial melting of Proterozoic crust-related mafic to intermediate rocks with significant crust–mantle interactions. The results, combined with regional magmatic information, indicate that the South Kunlun Oceanic plate might have experienced plate rollback in the late Permian and plate retraction in the Triassic under the Kunlun–Qaidam Block.

Objectives: The complex syn-sedimentary deformation structures induced by slump deposits in continental lacustrine basins are essential when interpreting paleotopography and ancient earthquakes. A systematic study on the slump deformation system is conducive to the identification of deformation origin,understanding of deformation mechanism and deeply interpretation of regional tectonic background.Methods: Based on a literature review,we summarize the forming conditions and deformation characteristics of slump deposits along the slope,especially the morphological evolution of slump folds,the associated deformation structures,indication of the ancient slope and physical simulation.Results: Comprehensive analysis shows that:（1） slump deformation in continental lacustrine basin is closely related to gravity flow deposition;（2）cylindrical fold and tight upright fold are at head of single slump body while mushroom-shaped fold at toe,the morphology evolution of these folds can be divided into several stages;（3）thrust faults,clastic dykes,irregular erosion surfaces and soft boudinage can be seen in slump folds;（4）stress mechanism and liquefaction mechanism are the two main mechanism of slump deformation;（5）physical simulation may become an important aspect of slump deformation study due to its changeable parameters of materials.Conclusions: Disputes still exist in the identification of deformation origin. Sediment reworking,remobilization,bioturbation and liquefaction of unconsolidated sediments are the key indicators of soft-sediment deformation.

In order to understand the geochemical characteristics of Paleozoic reservoir fluids in Xuanjing region, Lower Yangtze area, drilling core samples from Y and D wells were tested and analyzed to study the fluid inclusion types and composition. Pressure correction was undertaken to determine the temperature and pressure environment for inclusion formation, and the influence of fluid characteristics of the Upper Permian and Lower Triassic reservoirs on the preservation of shale gas was investigated. According to petrographic observations, fluid inclusions are mainly brine and bitumen inclusions. Bitumen inclusions are mainly distributed in holes and fractures, and with smaller individuals. No visible fluorescence was observed, and the vitrinite reflectance is 3.39%–3.92%. This indicates that there had been oil and gas accumulation in the early stage of diagenesis in the study area, but due to the influence of magmatic hydrothermal solution, oil and gas underwent thermal metamorphism in the early stage, making liquid petroleum into solid bitumen. At present, oil and gas in the reservoir were largely formed in the late stage. During the continuous process in which shale was buried, light oil and gas were generated. Light oil and gas underwent magmatic and tectonic hydrothermal processes in some areas, resulting in high-temperature metamorphic cracking that formed dry gas. Moreover, nitrogen inclusions are found in fluid inclusions, forming metamorphic fluids caused by magmatic hydrothermal activities. The study shows that Paleozoic reservoirs in Xuanjing area are characterized by self-generation and self-storage. Furthermore, the mechanism of shale gas accumulation is not only related to the buried hydrocarbon generation process of shale itself, but is also related to later magmatic activity and tectonic hydrothermal transformation. Therefore, preservation conditions are generally key factors of shale gas accumulation in this area.