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Petrology, Age and Geodynamic Implication of the Panafrican Granitoids Associated with the Glito-Kpatala shear zone (South-East Togo)

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International Journal of Geosciences 2023年第12期14卷 1193-1225页

作者： Gnanwasou Alayi Sarakawa Abalo Malibida Kpanzou Yao Agbossoumondé Essodina Padaro René-Pierre Menot Mahaman Sani Tairou Départment de Géologie Faculté des Sciences Université de Lomé Lomé Togo Laboratoire Magmas et Volcans Université Jean Monnet Saint Etienne France

The granitic plutons associated with the Glito-Kpatala shear zone are composed of biotite and amphibole granodiorites, biotite granites, two-mica granites and aplitic granites, which are very poorly represented. The chemical and mineralogical compositions of these facies indicate that they are I type and belong to high-K calc-alkaline series, with a chemical metaluminous character displayed by the granodiorites relative to the biotite and two-mica facies whose chemical compositions vary between metaluminous and peraluminous caracter. The Th/Ta (14.04 - 43.82 ppm, mean = 26.05), Th/U (2.58 to 15.05 ppm, mean = 5.85 ppm), Zr/Hf (25.27 to 37.21, mean = 30.67 ppm) and Rb/Sr (0.16 to 4.32;mean = 1.67 ppm) ratios of these granitoids reveal a strong crustal involvement in their magmatogenesis. Variations in CaO/Na2O (0.47 - 1.44 ppm), Rb/Sr (0.14 - 0.27 ppm), Rb/Ba (0.07 - 0.14 ppm) and Sr/Y (38.21 - 174.42 ppm) ratios indicate that biotite and amphibole granodiorites with their excessive Ni (135.37 - 139.51 ppm) and Cr (395.73 - 447.74 ppm) were derived from a mafic to intermediate lower continental crust where garnet and/or amphibole were stable residual assemblage minerals. The moderate Sr/Y ratios (1.81 - 9.47 ppm) and low transition elements Ni (1 - 6.44 ppm) and Cr (7.89 - 13.47 ppm) contents in both the two-mica and biotite granites are consistent with their emplacement at relatively shallow depths in the upper to mean continental crust, at pressures below 10 Kbar. In the two-mica granites, moderate CaO/Na2O (0.20 - 0.57 ppm, mean = 0.38 ppm) and Rb/Ba (0.39 - 1.37, mean = 0.84 ppm) ratios and quite varied Rb/Sr (1.53 - 4.23 ppm, mean = 2.85 ppm) ratios indicate a predominant derivation from psammitic and pelitic metasediments rather than metagreywackes. These low ratios (0.25 ≤ CaO/Na2O ≤ 0.32, mean = 0.28 ppm;0.31 ≤ Rb/Ba ≤ 0.44, mean = 0.39 ppm;1.11 ≤ Rb/Sr ≤ 1.78, mean = 0.39 ppm) in biotite granites are more consistent with melt

关键词： Pan-African Granitoids Post-Collisional shear zone South-East Togo

EXPERIMENTAL STUDY ON DEFORMATION FABRICS OF QUARTZ AND CALCITE IN shear zone

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地震地质 1987年第4期 10-17页

作者： Ma Sheng-li and Ma Jin(Institute of Geology, State Seismological Bureau)

Frictional experiments of samples with quartz and calcite sandwich have been operated under certain confining pressures, strain rate and different temperatures. Samples deformed and undeformed have been studied by means of microscope, TEM, and U-Stage. On the basis of this, changes of deformation micro-structures and fabrics of quartz and calcite aggragates with temperatures under condition of simple shear have been analyzed.

关键词： Frictional experiment shear zone Quartz Calcicte Microstructure Fabric

Right Lateral shear and Rotation in the Northeast of the Arabian-Iranian Collision zone

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Journal of Earth Science 2018年第3期29卷 616-628页

作者： Arash Barjasteh Deputy for Dam and Power Plant Development Khuzestan Water and Power Authority

Accommodation of continental convergence by crustal thickening and lateral transport is mainly featured as strike-slip faulting along the trends roughly orthogonai to the orientation of plate convergence. This style of faulting will affect seismicity of the involving areas which can be proved in low seismic zones by determining regional stress pattern using numerical methods. Accordingly, the stress distribution and deformation pattern of the South Sanandaj-Sirjan zone in the northeastern part of the Iranian-Arabian collision zone is investigated here using a three dimen-sional mechanical model. The modeled area is bounded between the Zagros thrust fault on the west and Dehshir-Baft fault in the east. The model is composed of three layers： the upper two layers represent the upper brittle and lower ductile crust of the collided continent and the lowest layer represents the lithospheric mantle. The upper crust behaves as an elastic material while the lower crust is considered as a non-Newtonian viscous fluid layer. The lithospheric mantle is taken as a low-viscosity material which is not allowed to move in any direction relative to the overlying layers. The Zagros thrust fault was treated with two different dip values saying 90° and 45° but Dehshir-Baft fault was modeled as a vertical fault and allowed to have a dextral movement regarding to the existing evidence. The driving mechanism applied to the western side of the model was chosen considering two different approaches including a kinematic approach （the Arabian-Eurasian convergence velocity; 35 mm/yr） and a dynamic approach （an external boundary force equal to 3.55E＋17 N）. The resulted stress field indicates an orogen-parallel component of right lateral shear along the Zagros fault implying a rotational deformation pattern within the modeled region that suggests a stress partitioning in the study area. The pattern also indicates a stress accumulation towards the south which could be a reason for the regional seis

关键词： Zagros thrust fault Sanandaj-Sirjan belt numerical modeling shear zone Eghlid-Deh Bid.

Structural Geology and Chronology of shear zones along the Shangdan Suture in Qinling Orogenic Belt,China:Implications for Late Mesozoic Intra-Continental Deformation of East Asia

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Journal of Earth Science 2024年第2期35卷 376-393页

作者： Falak Sheir Wei Li Le Zhang Basil Alabowsh Liuqing Jiang Li Liang Sainan Gao Shair Baz Umar Ashraf State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi’an710069China Institute of Geology University of PunjabLahore45590Pakistan

The Shangdan suture zone(SDZ)in the Qinling orogenic belt(QOB)is a key to understanding the East Asia tectonic *** SDZ gives information about convergent processes between the North China Block(NCB)and South China Block(SCB).In the Late Mesozoic,several shear zones evolved along the SDZ boundary that helps us comprehend the collisional deformation between the NCB and SCB,which was neglected in previous *** shear zones play an essential role in the tectonic evolution of the East Asia *** study focuses on the deformation and geochronology of two shear zones distributed along the SDZ,identified in the Shaliangzi and Maanqiao *** shear sense indicators and kinematic vorticity numbers(0.54–0.90)suggest these shear zones have sinistral shear and sub-simple shear deformation *** quartz’s dynamic recrystallization and c-axis fabric analysis in the Maanqiao shear zone(MSZ)revealed that the MSZ experienced deformation under green-schist facies conditions at∼400–500℃.The Shaliangzi shear zone deformed under amphibolite facies at∼500–700℃.The^(40)Ar/^(39)Ar(muscovite-biotite)dating of samples provided a plateau age of 121–123 *** with previously published data,our results concluded that QOB was dominated by compressional tectonics during the Late Early ***,we suggested that the Siberian Block moved back to the south and Lhasa-Qiantang-Indochina Block to the north,which promoted intra-continental compressional tectonics.

关键词： Qinling orogenic belt Shangdan suture zone shear zone Late Mesozoic intra-continental deformation East Asia tectonics

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

Tectonic Dynamic Metallization of Silver-GoldHydrothermal Fluids in Proterozoic GneissTerrene shear zones, Suichang, Zhejiang, China

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Journal of China University of Geosciences 2001年第1期12卷 68-74页

作者： Wang Siyuan Xiao Qibing Zeng Jianguo Faculty of Earth Resources, China University of Geosciences, Wuhan 430074 Faculty of Earth Resources China University of Geosciences

The Suichang mine is the largest silicified vein-type silver-gold mineralization system in Southeast China, whose ore bodies are controlled by shear zones developing in Lower Proterozoic gneiss terrene with initial migmatization, which is covered by Upper Jurassic and Lower Cretaceous volcanic rock system and cut by acidic igneous veins of Jurassic and Cretaceous. The conclusions are as follows: (1) The ore-forming fluid is defined as superhigh tectonic-metamorphic fluid on the base of : 1 (D)-(18O) values 2 fluid inclusions;3 trace elements of pyrite from ores. (2) The shear zone silicified orebod-ies occurred in proterozoic, Jurassic and Cretaceous, which have been transforms in part by ore-bearing comb quartz vein of volcanism.

关键词： tectonic dynamic metallization silver-gold hydrothermal fluids Proterozoic gneiss terrene shear zone Suichang field Cathaysian plate.

Geochronological Constraints for Boundary shear zones between Eastern Ghats Province and Bastar Craton: Implication for the Formation of Granulites and Their Exhumation History

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International Journal of Geosciences 2022年第8期13卷 593-608页

作者： Rajib Kar Miguel Angelo Stipp Basei Samarendra Bhattacharya Anwesha Ghosh Sanchari Chatterjee Department of Geology University of Calcutta Kolkata India Geoscience Institute Sao Paulo University Sao Paulo Brazil

shear zones in the boundary between Eastern Ghats Province (EGP) and the cratons of Singhbhum in the north and Bastar in the west provide an excellent opportunity to study the tectonics of shear zone development and its timing in relation to the evolutionary history of the granulite suites. Detailed structural, microfabric and quartz C-axis patterns revealed a high temperature shear zone, at the western boundary between EGP and Bastar Craton (BC) around Paikmal. Petrological studies in this shear zone indicated decompression coeval with stretching in the sheared granulites. Geochronological constraints provided here indicate rapid exhumation of deep seated granulites in this boundary shear zone;the timing also is late in relation to the long-lived thermal (granulite formation) event in the EGP. Additionally, our geochronological data demonstrated the ~1600 Ma event in the Eastern Ghats Belt (EGB) involving sedimentation, magmatism, metamorphism and crustal anatexis, as a significant world event.

关键词： shear zone Extrusion Tectonics Exhumation Eastern Ghats Province Geochronology

Kink-band Kinematic Analysis and its Implications for Late-stage Deformation in the Internal Parts of the Zagros Collision(Sanandaj–Sirjan zone) in West Iran

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 921-935页

作者： Maryam HEYDARI Mahdi BEHYARI Department of Geology Faculty of SciencesUrmia University57153165 UrmiaIran

In the internal parts of the Zagros collision zone, several deformation phases have been superimposed. The early deformation phase caused the development of a penetrative foliation. The late-stage deformation phase was preferentially accommodated within shear zones and caused the generation of shear bands, implying a non-coaxial component of deformation, the end of this stage deformation was marked by the development of kink-bands. In the vicinity of Zagros suture zone, the kink angle increased from 40° to 60°, and the kink-bands was converted to chevron folds. In this region, the external(α) and internal(β) angular ratio is α/β ≠ 1 and kink angle increased, and deformation occurred with 10% to 30% volume loss. Farther from the suture zone in the east, α/β = 1;and total volume was constant or increased by 5% to 10%. Kink-bands kinematic analysis in the study area revealed this structures were sensitive to deformation conditions and components such that, with decreasing distance to the Zagros suture zone, shearing and rotation increased, a high kinematic vorticity dominated, and volume loss occurred during deformation.

关键词： kink-band shear zone strain vorticity Zagros Iran

GIS based integration of multi-spectral remote sensing and morphostructural analysis for delineating potential areas of hydrocarbon exploration in Western Vindhyan Basin,India

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Energy Geoscience 2022年第2期3卷 191-201页

作者： Subhobroto Mazumde Ashish Misra Remote Sensing&Geomatics KDM Institute of Petroleum ExplorationOil and Natural Gas Corporation LimitedIndia

The Chambal Valley forms the western part of the Proterozoic Vindhyan Basin that has been less studied and poorly explored from the hydrocarbon perspective than its eastern counterpartdthe Son Valley *** the present manuscript,attempts have been made to use remote sensing and GIS(geographic information system)based analysis to focus on the northern part of Chambal Valley to decipher its tectonics and structural configuration,its tectonic relation with the Son Valley Vindhyans,Bundelkhand Massif and Ganga *** study also assumes significance as it attempts to delineate potential lead areas for hydrocarbon exploration in Chambal *** part of the study,a detailed spectral analysis based on image data sets is carried out to identify areas of microseeps as proxies of potential hydrocarbon ***,a neotectonics-based geomorphic analysis is carried out to delineate a fault network and geomorphic highs that act as aliases to subsurface faults and structural *** results are subsequently validated by available geophysical data and extensive fieldwork,and suggest four structural trends in the Chambal Valley as striking NE-SW,E-W,NW-SE and NeS,of which the NW-SE trend is the oldest,followed by the NE-SW,E-W and NeS trends.A GIS-based analysis of the E-W trends indicates that these are probably manifestations of the westward continuity of E-W-trending shear zones developed in Bundelkhand massif within the basement of the Chambal *** remote sensing studies of the shear zone network exposed in the Bundelkhand massif indicate the pattern to be replicated on a larger scale in the morphostructural fault layout in the adjacent Ganga Basin,implying these shear zones may be continuing in the basement of Ganga Basin and controlling structures developed later,and consequently the different petroleum system elements in the basin.A dip data based structural analysis of the Chambal Valley describes a regional synform attributed with an almost

关键词： Chambal Vindhyans Hydrocarbon Remote sensing shear zone Syncline