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A Uniform Orogen-parallel Extension System of the Shear Zones in the Tongbai-Dabie Orogenic Belt, Central China

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Acta Geologica Sinica(English Edition) 2018年第2期92卷 556-567页

作者： LIU Huan LIN Shoufa song chuanzhong Nanjing Center China Geological Survey Department of Earth and Environmental Sciences University of Waterloo School of Resources and Environmental Engineering Hefei University of Technology

Large-scale magmatism affected the Tongbai-Dabie orogenic belt during post-collisional lateral tectonic extension in the Cretaceous, which was suggested to account for the widespread deformation and migmatization in the Tongbai-Dabie complexes. However, it cannot explain the most deformations in the shear zones. The northwest-southeast shear zones are developed around or wrapped the Tongbai-Dabie complexes. They play an important role for the interpretation of the tectonic evolution of the Tongbai-Dabie orogenic belt. By a systematically observation and description of the geometry and kinematics of these shear zones, we found that the shear zones to the north dip NE and have a uniform sinistral shear sense, the shear zone to the south dips SW and has a uniform dextral shear sense, and the shear zones at the core are sub-horizontal and have a uniform top-to-NW sense of shear. Combining with the comparison of previous and our geochronological studies, we interpret these associations as indicating that these shear zones were originally a single, more flat-lying and sub- horizontal shear zone with a uniform top-to-NW shear sense before the folding-doming of the Tongbai- Dabie complexes and suggest that the Tongbai-Dabie orogenic belt experienced a uniform top-to-NW orogen-paraUel extension in the ductile lithosphere before the widespread magmatism in the Cretaceous.

关键词： Tongbai-Dabie orogenic belt shear zone Tongbai complex Dabie complex orogen-parallel extension

The constraints of strain partitioning and geochronology in Luonan-Luanchuan tectonic belts on Qinling orogenic belt

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Science China Earth Sciences 2009年第3期52卷 300-312页

作者： song chuanzhong ZHANG GuoWei WANG YongSheng LI JiaHao CHEN ZeChao CAI ZhiChuan School of Resources and Environment Hefei University of TechnologyHefei 230009China Department of Geology Northwest UniversityXi’an 710069China

The Luonan-Luanchuan tectonic belt lies between the North China Block and Qinling Mountains, in- cluding the Luonan-Luanchuan fault zone and the strong deformation zone to the north of the fault. The ductile shear zone, imbricate brittle fault and duplex structure in the fault zone now are the expression of the same tectonic event in different depth. Such lineation structure exists in the tectonic belts as mineral lineation, elongation lineation, crenulation lineation, sheath folds and so on, indicating NE-directed plate motion. Fold axes and thrusts in the strong deformation zone are inclined to the Luonan-Luanchuan fault zone at small angles. The structures with different natures show a regular pattern, produced during oblique convergence of plates. The convergence factors are as follows:The direction of plate convergence is 22°, 31° and the angle between the plate convergence direction and plate boundary is 73°, 82° respectively in the west and east segment. The Luonan-Luanchuan tectonic belt was deformed strongly in 372 Ma, resulted from Erlangping back-arc ocean basin subduction sin- istrally and obliquely to North China Block during the collision of North China Block and South China Block.

关键词： Qinling orogenic belt oblique convergence convergence factor strain partitioning continental accretion

Tectonic Characteristics, Evolution, and Significance of the Zhouwang Fault, Lower Yangtze Area, Eastern China

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Acta Geologica Sinica(English Edition) 2022年第2期96卷 460-476页

作者： ZHANG Gang CHEN Guangtao REN Shenglian GE Can LIN Shoufa song chuanzhong LI Longming School of Resources and Environmental Engineering Hefei University of TechnologyHefei 230009China Institute of Geophysical and Geochemical Prospecting Techniques of Anhui Province Hefei 230022China Department of Earth Sciences University of WaterlooWaterloo N2L3G1OntarioCanada

Fault geometry, kinematics, geophysics, the tectonic stress field and tectonic evolution of the Zhouwang fault in the southern Jiangnan tectonic transition zone of the Lower Yangtze region, eastern China are examined. Field observations show the fault is composed of a series of nearly E–W trending, N–S dipping faults, and four stages of tectonism(sinistral strike-slip, thrust nappe, normal fault, and dextral strike-slip) developed in turn. Geophysical data show that the fault trends almost linearly E–W along a flat, steep gravity gradient at shallow depth, with distinct gravity anomalies to the north and south and different in the north and south. Also, the deep part is characterized by northward dip and a gradual slowing down. Tectonic stress field analysis indicates that the fault experienced four tectonic movements: NNE–SSW compression, NNW–SSE compression, NEE–SWW extension, and E–W compression. Combined with regional tectonic background and previous research results, this indicates that:(1) the Zhouwang fault experienced sinistral strike-slip movement during the Indosinian Period(260–200 Ma);(2) thrust nappes developed during the early Yanshanian Period(163–145 Ma);(3) a normal fault occurred in the late Yanshanian Period(125–65 Ma);and(4) dextral strike-slip movement occurred in the Himalayan Period(ca. 50–37 Ma). The results reveal the tectonic evolution of the fault during Mesozoic deformation in the area, and also reveal the geological evolution and tectonic transformation of the Lower Yangtze region, which is key to our understanding of intracontinental deformation in eastern China.

关键词： bouguer gravity anomaly stress field tectonic evolution Zhouwang fault Lower Yangtze

Zircon U-Pb geochronology of the volcanic rocks from Fanchang-Ningwu volcanic basins in the Lower Yangtze region and its geological implications

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Chinese Science Bulletin 2009年第16期54卷 2895-2904页

作者： YAN Jun LIU HaiQuan song chuanzhong XU XiSheng AN YaJun LIU Jia DAI LiQun School of Resources and Environmental Engineering Hefei University of Technology Hefei 230009 China State Key Laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing 210093 China

The latest eruptions in two important Mesozoic volcanic basins of Fanchang and Ningwu located in the middle-lower reaches of the Yangtze River formed the bimodal volcanic rocks of the Kedoushan Formation and ultrapotassic volcanic rocks of the Niangniangshan Formation, respectively. The repre-sentative volcanic rocks of the two Formations were selected for LA-ICPMS zircon U-Pb dating. The results indicate that there exist a large amount of magmatic zircons as indicated by high Th/U ratios in these volcanic rocks. The weighted mean age of 21 analyses is 130.7±1.1 Ma for the Kedoushan Formation, and that of 20 analyses is 130.6±1.1 Ma for the Niangniangshan Formation. These U-Pb ages are interpreted to represent the formation times of the volcanic rocks. In combination with other known geochronological data for Mesozoic volcanic rocks from the Lower Yangtze region, it is proposed that the latest volcanic activations in the Jinniu, Luzong, Fanchang and Ningwu volcanic basins probably came to end prior to ca. 128 Ma. There is no significant time interval between the early and later volcanic activities in the Luzong and Ningwu basins, suggesting a short duration of volcanic activities and thus implying the onset of an extensional tectonic setting at about 130 Ma in the Lower Yangtze region. Integrated studies reveal that the Early Cretaceous magmatic activities and their geochronological framework in the Lower Yangtze region are a response to progressively dynamic deep processes that started with the transformation of tectonic setting from compression to extension, followed by delaminating of the lower part of the thickened lithosphere, lithospheric thinning, asthenosphere upwelling, and crust-mantle interaction.

关键词：火山岩盆地长江下游地区地质意义年代学锆石定年 Pb

The Geological Significance of the Deformation and Geochronology of the Xiaotian–Mozitan Shear Zone in the Dabie Orogenic Belt(East-Central China)

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Acta Geologica Sinica(English Edition) 2021年第2期95卷 370-392页

作者： HUANG Peng song chuanzhong XIAO Wenjiao LI Jiahao ZHOU Kefa WANG Jinlin NIJIATI Abuduxun LI Zhenwei Slate Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUramqi 830011China Xinjiang Research Center for Mineral Resources Chinese Academy of SciencesUrwnqi 830011China Xinjiang Key Laboratory of Mineral Resources and Digital Geology Urumqi 830011China School of Resources arid Environmental Engineering Hefei University of TechnologyHefei 230009China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100049China College of Earth and Planetary Sciences University of the Chinese Academy of SciencesBeijing 100049China Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Science Chinese Academy of SciencesBeijing 100101China Xinjiang Key Laboratory for Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt School of Geology and Mining EngineeringXinjiang UniversityUrumqi 830046China

The Xiaotian–Mozitan Shear Zone(XMSZ)is the boundary of the Dabie High-grade Metamorphic Complex(DHMC)and the North Huaiyang Tectonic *** was deformed in ductile conditions with a top-to-NW/WNW *** applied to mineral parageneses in mylonites of the shear zone give a temperature range of 623–691°C for the predeformation and 515–568°C for the syndeformation,respectively,which indicates a retrograde process of evolution.A few groups of zircon U-Pb ages were obtained from undeformed granitic veins and different types of deformed rocks in the *** from the felsic ultramylonites are all magmatic,producing a weighted mean 206Pb/238U age of 754±8.1 Ma,which indicates the time of magmatic activities caused by rifting in the *** from the granitic veins,cutting into the mylonites,are also of magmatic origin,producing a weighted mean 206 Pb/238 U age of 130±2.5 Ma,which represents the time of regional magmatic activity in the *** from the mylonitic gneisses are of anatectic-metamorphic origins and are characterized by a core-mantle interior texture,which yielded several populations of ages including the Neoproterozoic ages with a weighted mean 206 Pb/238 U age of 762±18 Ma,similar to that of the felsic ultramylonites and the Early Cretaceous ages with a weighted mean 206Pb/238U age of 143±1.8 Ma,indicating the anatectic metamorphism in the Dabie Orogenic Belt(DOB).Based on integrated analysis of the structure,thermal conditions of ductile deformation and the contact relations of the dated rocks,the activation time of the Xiaotian–Mozitan Shear Zone is constrained between~143 Ma and 130 Ma,during which the DOB was undergoing a transition in tectonic regime from compression to ***,the deformation and evolution of this shear zone plays an instrumental role in fully understanding this *** research also inclines us to the interpretation of it as an extensional detachment,with regard to the te

关键词： syndeformation temperature zircon U-Pb dating tectonic regime transition Xiaotian-Mozitan Shear Zone Dabie Orogenic Belt

Deformation of the Shirenshan Block in the North Qinling

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Acta Geologica Sinica(English Edition) 2017年第1期91卷 351-352页

作者： WANG Jingya REN Shenglian LI Jiahao LI Quanzhong song chuanzhong LI Longmin LIN Shoufa HUANG Yonglong HAN Xu LI Zhenqiang Hefei University of Technology Hefei 230009 Anhui China University of Waterloo Waterloo Ontario N2L 3G1 Canada University of Science and Technology of China Hefei 230026 Anhui China

Objective The Qinling orogenic belt is a typical complex continental orogenic belt which has experienced multiperiod tectonic evolution and where some important tectonic belts *** Luoluan fault is one of the most important belts,which is the boundary fault of the North China Plate and the Qinling orogenic *** Shirenshan block is located in the north section between Luanchuan and Fangcheng of the Luoluan fault.

关键词： Deformation of the Shirenshan Block in the North Qinling

New Zircon U-Pb Ages of the Shirenshan Gneiss, North Qinling and Their Geological Implications

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Acta Geologica Sinica(English Edition) 2019年第1期93卷 238-240页

作者： WANG Jingya REN Shenglian JIANG Dazhi DONG Shuwen LI Jiahao LI Longming GE Can song chuanzhong HAN Xu LI Zhenqiang School of Resources and Environmental Engineering Hefei University of Technology School of Earth Sciences Western University School of Geoscience and Engineering Nanjing University

The Qinling Orogenic Belt(QOB)is a composite continental orogenic belt that has experienced many tectonic *** QOB is subdivided into the following three litho-tectonic units:the North Qinling terrane,the Middle Qinling microplate and the South Qinling *** North Qinling Terrane(NQT)underwent destruction and lithospheric thinning during the late Mesozoic,accompanied by extensive magmatic activity and increased surface heat flux,led to large-scale tectonic extension(e.g.,Ren Shenglian et al.,2016).The Shirenshan gneiss is located along the contact between the NQT and the North China Block(Fig.1).Previous studies suggested that it was produced as a result of the northward subduction of the NQT beneath the North China Block(e.g.,Wang Jingya et al.,2017).Therefore,it is significant to study its structural geology,petrology,geochemistry and chronology in order to understand the tectonic settings and the interaction between the Middle Qinling microplate and the North China Block.

关键词： The Qinling Orogenic Belt(QOB) subdivided The North Qinling Terrane(NQT)

Mineralogical Characteristics of Garnet in Garnet Mica Schist and Its Tectonic Significance in the Tongbai Section of the Shangdan Fault Zone

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Open Journal of Geology 2015年第1期5卷 13-27页

作者： Shenglian Ren chuanzhong song Jiahao Li School of Resources and Environmental Engineering Hefei University of Technology Hefei China

Studies on the metamorphism and deformation conditions of rocks in the suture zone are good ways to discuss the orogenic process and mechanism. The microstructure and ultramicrostructure features of minerals are true embodiment of formation environment of the orogenic belt. Based on the study of microstructure, ultramicrostructure deformation characteristic and compositional zonation of garnets in garnets-mica schists in the Tongbai mountain, east section of the Shangdan fault zone, the results show that the three types of garnets have suffered various states of plastic deformation. The dynamic recrystallization of garnets is due to the subgrain growth and boundary migration. The dislocations are mainly free dislocation and dislocation walls. The free dislocation density ρ = 6.14 × 108/cm2, and dislocation movement are mainly slips;slip planes are 1/2 {110} and {001}. Garnet microprobe analysis shows that it belongs to almandine, and reflects it has undergone epidote-amphibolite to amphibolite facies metamorphism. Compositional zonation of garnet shows that the rocks had experienced progressive metamorphism. First metamorphic environment was continuous temperature-pressure and in mid-term there were two non-synchronous transient cooling and decompression processes, and it finally underwent decompression and warming process of the thermal relaxation environment. The formation condition of garnet-mica schist is estimated: T = 562°C - 617°C, and P = 0.77 - 1.02 GPa. The differential stress is 0.511 GPa and strain rate is 4.97536 × 10-10 m/s. After systemic analysis, a conclusion is drawn that the plastic deformation mode, deformation mechanism and formation environment of garnets are closely related to the formation and development of the Shangdan fault zone. It truly reflects that the Shangdan fault zone, as the suture zone of Yangtze and north China plate, has been subjected to early medium-grade metamorphism. With the continuous compression after the collision, the

关键词： The Tongbai Area The Shangdan Fault Zone Metamorphism and Deformation Compositional Zonation of Garnet Dislocation

RELATIONSHIP BETWEEN P-T CONTITIONS OF TWO PHASES OF TAN-LU STRIKE-SLIP SHEAR ZONES AND DELAMINATION OF OROGENIC BELTS ON THE EASTERN MARGIN OF THE DABIE MOUNTAINS

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Geotectonica et Metallogenia 2005年第2期29卷 139-151页

作者： WANG Yongsheng ZHU Guang WANG Daoxuan LIU Guosheng song chuanzhong College of Resource and Environmental Engineering Hefei University of Technology Hefei Anhui 230009 China

The Tan-Lu fault zone joins the Dabie Mountains on its eastern margin, and offsets the Dabie and Sulu orogenic belts sinistrally for about 500 kin. On the basis of calculation of temperature and pressure experienced by the two phases of the fault zone as well as the thermo-chronological information on mylonite from the earlier and later Tan-Lu fault zones on the eastern margin of the Dabie Mountains, this paper discusses the delamination history and uplifting magnitudes of the Dabie Mountains from earlier Jurassic to earlier Cretaceous. From mineral assemblages, mineral deformation and muscovite-chlorite geothermometry calculation, it is known that the temperature experienced by the two phases of Tan-Lu fault zones are between 40℃ and 450℃, and the confining pressures are between 0.25Gpa and 0.36GPa for the earlier shear zones and 0.24-0.39GPa for the late shear zones. According to the geobarometry of Si-in-phengite and by considering shear heating and tectonic over-pressure, it is concluded that the maximum formation depths for the two phases of the ductile shear zones are not more than 12 kin. Differential formation depths for the two phases of shear zones are 1-2 km at most. At about 190 Ma and 128 Ma, the Tan-Lu fault zone experienced two phases of cooling events. During this period, the eastem margin of the Dabie Mountains experienced a tectonic calm period and no uplifting. According to information from the Tan-Lu fault zone, the uplifting magnitudes of the Dabie orogenic belts are not more than 12 km during the earlier Cretaceous.

关键词： eastern margin of DaNe Mountains Tan-Lu fault zone orogenic delamination phengite thermometry