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Zhang X.,Jilin University | Wang K.,Jilin University | Wang K.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | Fu L.,Inner Mongolia Shandong Gold Geological Minerals Survey Co. | And 4 more authors.
Resource Geology | Year: 2017

The Bujinhei Pb–Zn deposit is located in the southern Great Xing'an Range metallogenic belt. It is a representative medium- to high-temperature hydrothermal vein type deposit controlled by fractures, and orebodies hosted in the Permian Shoushangou Formation. The hydrothermal mineralization is classified into three stages: pyrite ± arsenopyrite–quartz (Stage 1), polymetallic sulfide–quartz (Stage 2), and polymetallic sulfide–calcite (Stage 3). Fluid inclusion petrography, laser Raman analyses and microthermometry indicate that the liquid-rich aqueous inclusions (L) and vapor-rich CO2 ± CH4–H2O inclusions (C) occur in the Stage 1 and as medium- to high- temperature and low- to medium-salinity NaCl–H2O–CO2–CH4 hydrothermal fluids. The liquid-rich (L) and rare vapor-rich CO2 ± CH4–H2O inclusions (C) occur in the Stage 2 with medium-temperature and low-salinity NaCl–H2O ± CO2 ± CH4 hydrothermal fluids. The exclusively liquid-rich (L) fluid inclusions are observed in the Stage 3, and the hydrothermal fluid belongs to medium-temperature and low-salinity NaCl–H2O hydrothermal fluids. The results of hydrogen and oxygen isotope analyses indicate that ore-forming fluids were initially derived from the magmatic water and mixed with local meteoric water in the late stage (δ18OH2O-SMOW = 6.0 to 2.2‰, δDSMOW = −103 to −134‰). The carbon isotope compositions (−18.4‰ to −26.5‰) indicate that the carbon in the fluid was derived from the surrounding strata. The sulfur isotope compositions (5.7 to 15.2‰) indicate that the ore sulfur was also primarily derived from the strata. The ore vein No. 1 occurs in fractures and approximately parallel to the rhyolite porphyry; orebodies have a close spatial and temporal relationship with the rhyolite porphyry. The rhyolite porphyry yielded a crystallization age of 122.9 ± 2.4 Ma, indicating that the Bujinhei deposit may be related to the Early Cretaceous magmatic event. Geochemical analyses reveal that the Bujinhei rhyolite porphyry is high in K2O and peraluminous, and derived from an acidic liquid as a result of strong interaction with hydrothermal fluid during the late magmatic stage; it is similar to A2-type granites, and formed in a backarc extensional environment. These results indicate that the Bujinhei Pb–Zn deposit was a vein type system that formed in Early Cretaceous and influenced by the Paleo-Pacific tectonic system. Bujinhei deposit is a representative hydrothermal vein type deposit on the genetic types, and occurs on the western slope of the southern Great Xing'an Range. The ore-forming fluids were medium- to high-temperature and low-to medium-salinity NaCl–H2O–CO2–CH4 hydrothermal fluids, which became medium-temperature and low-salinity NaCl–H2O hydrothermal fluids in later stages, and came from magmatic water and mixed with meteoric water, whereas the ore-forming materials were mainly derived from the surrounding strata. The LA–ICP–MS zircon U–Pb dating indicates that the Bujinhei deposit formed at the period of late Early Cretaceous, potentially in a backarc extensional environment influenced by the Paleo-Pacific tectonic system. © 2017 The Society of Resource Geology


Li W.,Jilin University | Li W.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | Liu Y.,Jilin University | Liu Y.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | And 10 more authors.
Journal of Asian Earth Sciences | Year: 2017

The North China Craton (NCC) is one of the oldest cratons in the world, and it recently becomes a hot study area because of large volumes of Mesozoic intrusions associated with lithospheric thinning contributing to cratonic destruction in late Mesozoic times. However, the timing of initial thinning and destruction is still controversial. The Taili area, western Liaoning Province, in the northeastern part of the NCC well exposes the Archean basement rocks and the Mesozoic magmatic rocks with variable plastic deformation. This study focuses on the syntectonic emplacement of the Triassic biotite-syenogranite intrusions, in order to understand their petrogenesis, timing as well as the geological significance. Zircon LA-ICP-MS U-Pb ages reveal that the biotite-syenogranites formed between 246 and 191Ma, and contain many ancient (2564-2317Ma) zircon xenocrysts. Geochemical data suggests that the biotite-syenogranites display an adakitic affinity with high Sr/Y=135-167 and (La/Yb)N =48-69, as well as negligible Eu anomalies (δEu=0.87-0.94), high negative zircon εHf(t) values (-15.5 to -21.5) and ancient TDM2 ages (2246-2598Ma). This data suggests that the parent magmas were generated from partial melting of thickened Archean lower crustal rocks probably due to the bidirectional amalgamation of the NCC with the NE China micro-blocks and the Yangtze Craton in its north and south, respectively. In the middle part of the Taili area, magmatic fabrics are well preserved in the biotite-syenogranite intrusion characterized by the strong preferred orientation of biotite and hornblende crystals, which parallel to the intrusion margin and are slightly oblique to the gneissosity of the sheared host Neoarchean granitic gneisses. The quartz grain size piezometer suggests that the paleo-differential stresses weaken toward to the central part of the intrusion, ranging from 21.40-22.22MPa to 16.74-19.34MPa, during quartz crystallization in the emplacement stage. This allow deduce much higher strain rates in the center (1.26×10-11-2.24×10-9 s-1) than at the margin (9.07×10-12-1.31×10-9 s-1) of the pluton. These observations are interpreted by the rheological behavior of magma during the magmatic "pipe" flow. The adakitic source melts ascended through the conduits along weak NE-trending sinistral shear zones, and emplaced at the shallower depth of ∼16km before Early Jurassic (∼190Ma). The biotite-syenogranites were still in a semisolid state, when garnet-bearing granitic aplites injected at ∼220Ma. This stage records elongate (constrictional) strain under the sinistral shear stresses, particularly in quartz grains occurring in the margin of intrusions. In combination with previous studies, an exhumation rate of the NCC's Archean basement (from ∼25km to ∼11km in depth) is calculated as initial low exhumation rate of ∼4.0mm/kyr from Neoarchean to Late Triassic, and subsequent a rapid exhumation process of ∼63mm/kyr between Late Triassic to Early Cretaceous. All the results presented here allow us to consider the geodynamic evolution of the eastern NCC and constrain the onset of lithospheric thinning and cratonic destruction of the NCC as early as Middle Triassic (∼240Ma) triggered by the amalgamation of adjacent blocks. It developed prosperously since Late Triassic, due to the oblique subduction of the Paleo-Pacific Plate. © 2017 Elsevier Ltd.


Li J.,Jilin University | Li J.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | Liu Y.-J.,Jilin University | Liu Y.-J.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | And 12 more authors.
Journal of Asian Earth Sciences | Year: 2017

The North China Craton is one of the major Archean to Paleoproterozoic cratons in the world and oldest craton in China, which preserves a large amount of ancient basement and abundant structures showing the early earth tectonics. The controversy over the Archean tectonic regimes has lasted several decades centering around horizontal and vertical tectonics, the two classical tectonic models for Archean times. Thus, more studies of the early crustal growth and tectonic evolution are requisite for better understanding geodynamic regimes in the early Precambrian. This study provides an example for revealing of Archean tectonics. The NWN-trending, ENE-dipping Baijiafen ductile shear zone is located in the eastern Anshan of the northeastern North China Craton and mainly comprises two types of gneisses, including the Chentaigou porphyritic granitic gneiss and the Baijiafen trondhjemitic gneiss. In this study, we have carried out a detailed study on the macrostructure, microstructure and fabric characteristics of the two main types of deformed gneisses within the shear zone. The ribbon structures formed by intensely elongated quartz grains are widespread in these gneisses. Well-developed mineral stretching lineations and asymmetric fabrics indicate an ESE-directed downward shearing. The quartz c-axis fabric patterns obtained by electron backscatter diffraction technique imply low to middle temperature non-coaxial deformation with active rhomb 〈a〉 slip and basal 〈a〉 slip. Deformation behaviors of minerals and quartz crystallographic preferred orientations demonstrate that the rocks underwent mylonitization at a temperature of 400-500. °C under greenschist facies metamorphic conditions. Dislocation creep is the main rock deformation mechanism within the shear zone. Finite strain measurement results suggest that the strain types of the shear zone are generally related to elongate-plane deformation, and the tectonites change from L-S- to LS-type across the shear zone. The strain intensity increases obviously towards east, and the Baijiafen gneiss unit is located within the high-strain zone. Kinematic vorticity values of gneisses indicate that the deformed rocks were produced by steady-state simple-shear dominated general shear. Based on abundant structural evidence and previous studies, we infer that the deformation of the Baijiafen ductile shear zone may have resulted from the downward adjoining rock flow during the sagduction of the banded iron formations and synchronous Archean granite dome emplacement, supporting a vertical tectonic regime in Archean times. © 2017 Elsevier Ltd.


Yang Q.,Jilin University | Ren Y.,Jilin University | Ren Y.,Key laboratory of Mineral Resources Evaluation in Northeast Asia | Chen C.,Jilin University | And 2 more authors.
Geological Bulletin of China | Year: 2015

The Dongfengbeishan molybdenum deposit is located in northeastern Tianbaoshan ore concentration area in Yanbian Prefecture, Northeast China. Almost all discovered orebodies are controlled by faults and fractures in biotite quartz diorite, and characterized by veins and veinlets. The deposit experienced three metallogenic stages, namely quartz-molybdenite stage, quartz-polymetallic sulfide stage and quartz-calcite stage. Fluid inclusions in ore-bearing quartz veins can be classified into liquid-rich phase, gas-rich phase, daughter mineral-bearing three-phase and minor CO2-bearing three-phase occasional pure CO2 inclusions. Fluid boiling occurred during ore-forming evolution and might have played a very important role in metal elements precipitation. Besides H2O vapor, the gas phase in different types of inclusions, analyzed by Laser Raman Spectrum, also contains small amounts of CO2 and CH4, which indicates that the ore-forming fluid belongs to the H2O-NaCl±CO2±CH4 magmatic fluid system with medium-high temperature and medium-high salinity. The discovered vein molybdenum orebodies in the Dongfengbeishan molybdenum deposit resulted from the porphyry molybdenum mineralization, which implies that the metallogenic porphyry intrusion should have occurred under the biotite quartz diorite. The veinlet disseminated molybdenum mineralization has important guiding implications for further theoretical research and geological prospecting. ©, 2015, Science Press. All right reserved.


Feng Z.,Jilin University | Feng Z.,Northwest University, China | Feng Z.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | Liu Y.,Jilin University | And 6 more authors.
International Journal of Earth Sciences | Year: 2015

Jifeng ophiolitic mélange (ultramafic rocks, meta-basalts and gabbros) crops out in the northern segment of the Great Xing’an Range, the eastern segment of the Central Asian Orogenic Belt, which marks the closure of the Xinlin–Xiguitu Ocean associated with the collision between the Erguna block and Xing’an block. In order to investigate the formation age and magma source of the Jifeng ophiolitic mélange, the gabbros from newly discovered the Jifeng ophiolitic mélange are studied with zircon U–Pb ages, whole-rock geochemistry and zircon Hf isotopes. Zircon U–Pb dating from the ophiolitic gabbros yields U–Pb age of 647 ± 5.3 Ma, which may represent the formation age of the ophiolitic mélange. The gabbros display low SiO2, TiO2, K2O contents, high Na2O, LREE contents and indistinctive REE fractionation [(La/Yb)N = 1.97–2.98]. It shows an E-MORB-like affinity, while the element concentrations of the Jifeng samples are lower than that of E-MORB. More importantly, Nb displays negative anomaly in comparison with Th, which shows a transitional SSZ-type ophiolite signature. Moreover, the εHf (t) values of ~647 Ma zircons in the gabbros range from +8.4 to +13.4, and the corresponding Hf single-stage ages (TDM1) are between 687 and 902 Ma, which is obviously older than the crystallization age of 647 Ma. These geochemical features can be explained as melts from the partial melting of a depleted mantle source meta-somatized by fluids derived from a subducted slab. Accordingly, we conclude that the Jifeng ophiolitic mélange is probably related to transitional SSZ-type ophiolite and developed in an intra-oceanic subduction, which indicates that an ocean (the Xinlin–Xiguitu Ocean) existed between the Erguna block and Xing’an block. The Ocean’s formation might be no later than the Neoproterozoic (647 Ma), and it was closed in the Late Cambrian because of the collision between the Erguna block and Xing’an block. © 2015 Springer-Verlag Berlin Heidelberg


Hao Y.-J.,Jilin University | Ren Y.-S.,Jilin University | Ren Y.-S.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | Yang Q.,Jilin University | And 4 more authors.
Resource Geology | Year: 2015

The Gaogangshan Mo deposit, located in the northern part of the Lesser Xing'an Range (the eastern part of the Xing'an-Mongolia Orogenic Belt), is one of the newly discovered Mo deposits in northeast China. Ore bodies occur in the granite and are generally in vein and stockwork forms. Major metallic minerals in the ore include pyrite and molybdenite. The styles of mineralization are disseminated, veinlet-disseminated, and veinlet. The major types of wall-rock alteration are silicification-potassic alteration, phyllic alteration and propylitization. Fluid inclusion analyses indicate that the ore-forming fluid during the major mineralization stage is an H2O-NaCl-CO2 system, with wide homogenization temperature and salinity ranges. The abundant CO2-rich and coexisting halite-bearing fluid inclusion assemblages in the main stage of mineralization highlight the significance of intensive fluid boiling for porphyry Mo mineralization. Comprehensive study of the ore-forming conditions, geological features of the deposit, micro-thermometric analysis of fluid inclusions and comparison of the Gaogangshan deposit with other typical porphyry deposits leads to the conclusion that the deposit is a porphyry type. We obtained a weighted mean age of the molybdenite deposit at Gaogangshan of 250.7±1.8 Ma. The isotopic dating results indicate that the Gaogangshan deposit was formed in the Permo-Triassic, which is the earliest Mo-only deposit in northeast China. The formation of the Gaogangshan Mo deposit may be related to the extension and break-up of the Songnen Block and Jiamusi Block in the Permo-Triassic. © 2015 The Society of Resource Geology.


Liu Y.,Jilin University | Liu Y.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | Liu B.,Jilin University | Liu B.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | And 6 more authors.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2016

Laodaokou unit is located in Oroqen Autonomous Banner, Inner Mongolia, the east of Xing'an Mongolian orogenic belt, northern Great Xing'an Range. The unit is mainly composed of diorite, adamellite, and dioritic porphyrite. SIMS U-Pb dating of zircon of the diorite provides the age of (126.09±0.95) Ma, indicating that the plution was formed in Early Cretaceous instead of Cambrian as thought before. The major element data show that the diorites contains 56.13%-57.91% of SiO2, 0.97%-0.99% of TiO2, 2.00%-2.12% of MgO, 6.73%-7.41% of TFe2O3, 36.00-38.00 of Mg#, 4.29%-4.53% of Na2O, 1.38%-1.59% of K2O, 17.95%-18.36% of Al2O3. The K2O/Na2O ratios range from 0.31 to 0.37. The diorites are rich in alumina and sodium relatively. The rare earth elements chondrite standardized curves show that they are rich in light REE and depleted of heavy REE with weak negative δEu (0.85-0.87). Laodaokou plution is rich in large ion lithophile element (LILE) (e.g., Ba, K, Rb, Th, U), but depleted of high field strength elements (HFSE) (e. g., Nb, Ta, Ti, and P). The geochemical signatures above imply a characteristic related to subduction, and this suggests that the magmatic source of Laodaokou diorites were from the lithospheric mantle, which was metasomatosed by subduction fluid. Combining with the geochemical characteristics of Laodaokou plution and its regional tectonic settings, we conclude that the plution might be formed under a lithospheric extension after the closure of Mongolia-Okhotsk Ocean. © 2016, Jilin University Press. All right reserved.


Chen C.,Jilin University | Ren Y.-S.,Jilin University | Ren Y.-S.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | Zhao H.-L.,Jilin University | And 3 more authors.
International Geology Review | Year: 2014

The Wudaogou Group in eastern Yanbian, Northeast China, plays a key role in constraining the timing and eastward termination of the Solonker-Xra Moron River-Changchun Suture, where the Palaeo-Asian Ocean closed. The Wudaogou Group consists of schist, gneiss, amphibolite, metasedimentary, and metavolcanic rocks, all of which underwent greenschist- to epidote-amphibolite-facies regional metamorphism, with some hornfels resulting from contact metamorphism. To determine the age of deposition, the timing and grade of metamorphism, and the tectonic setting of the Wudaogou Group, we investigated the petrography and geochronology of the metamorphic rocks in this group. Zircons from the metasedimentary rocks of this group can be divided into metamorphic zircons and detrital zircons of magmatic origin. U-Pb ages of metamorphic zircons dated by LA-ICP-MS vary from 249 ± 4 to 266 ± 4 Ma, approximating the age of regional metamorphism in the eastern Yanbian area. Detrital zircons yield U-Pb ages ranging from 253 ± 5 to 818 ± 5 Ma, and indicate that the provenance of the Wudaogou Group experienced four tectonic-thermal events between 818 and 253 Ma: Neoproterozoic (ca. 818-580 Ma), Cambro-Ordovician (ca. 500-489 Ma), Devonian-Carboniferous (ca. 422-300 Ma), and middle-late Permian (ca. 269-253 Ma). The youngest detrital zircon, with a U-Pb age of 253 ± 5 Ma, defines the maximum depositional age of the Wudaogou Group. The presence of the Cambro-Ordovician and Neoproterozoic detrital zircons implies that the source of the Wudaogou Group had an affinity with Northeast China, which leads us to conclude that the Solonker-Xra Moron River-Changchun Suture extends from Wangqing to Hunchun in eastern Yanbian, and that the Palaeo-Asian Ocean may have closed at the end of the Permian or Early Triassic period. © 2014 Taylor & Francis.


Liu Y.,Jilin University | Liu Y.,Key laboratory of Mineral Resources Evaluation in Northeast Asia | Liu Y.,Northwest University, China | Li W.,Jilin University | And 8 more authors.
Gondwana Research | Year: 2016

The Central Asian Orogenic Belt (CAOB) is the largest accretionary orogen in the world, which is responsible for considerable Phanerozoic juvenile crustal growth. The NE China and its adjacent areas compose the eastern segment of the CAOB, which is a key area for providing important evidence of the CAOB evolution and understanding the NE Asian tectonics. The eastern segment of the CAOB is composed tectonically of four micro-blocks and four sutures, i.e. Erguna block (EB), Xing'an block (XB), Songliao-Xilinhot block (SXB), Jiamusi block (JB), Xinlin-Xiguitu suture (XXS), Heihe-Hegenshan suture (HHS), Mudanjiang-Yilan suture (MYS) and Solonker-Xar Moron-Changchun-Yanji suture (SXCYS). The EB and XB were amalgamated by westward subduction, oceanic island accretions and final collision in ca. 500. Ma. The XB and SXB were amalgamated by subduction-related Early Paleozoic marginal arc, Late Paleozoic marginal arc and final collision in the late Early Carboniferous to early Late Carboniferous. The JB probably had been attached to the SXB in the Early Paleozoic, but broken apart from the SXB in the Triassic and collided back in the Jurassic. The closure of Paleo-Asian Ocean had experienced a long continue/episodic subduction-accretion processes on margins of the NCC to the south and the SXB to the north from the Early to Late Paleozoic. The final closure happened along the SXCYS, from west Solonker, Sonid Youqi, Kedanshan (Keshenketengqi), Xar Moron River through Songliao Basin via Kailu, Tongliao, Horqin Zuoyizhongqi, Changchun, to the east Panshi, Huadian, Dunhua, Yanji, with a scissors style closure in time from the Late Permian-Early Triassic in the west to the Late Permian-Middle Triassic in the east. The amalgamated blocks should compose a united micro-continent, named as Jiamusi-Mongolia Block (JMB) after Early Carboniferous, which bounded by Mongo-Okhotsk suture to the northwest, Solonker-Xar Moron-Changchun suture to the south and the eastern margin of JB to the east. © 2016 International Association for Gondwana Research.


Chen C.,Jilin University | Ren Y.,Jilin University | Ren Y.,Key Laboratory of Mineral Resources Evaluation in Northeast Asia | Zhao H.,Tianjin Institute of Geology and Mineral Resources | And 2 more authors.
Resource Geology | Year: 2015

The late Paleozoic Wudaogou Group, one of the oldest metamorphic units in the eastern Yanbian area, has important tectonic and metallogenic significance. Here, we provide new insights into their protoliths, tectonic setting of the metamorphic rocks and their relationships with the gold and tungsten mineralization, using new petrographic and whole-rock geochemical data for various lithologies within the Wudaogou Group. The protolith of the metamorphic rocks of the Wudaogou Group was intermediate-basic volcanic rocks (e.g. basaltic andesite, trachyandesite, and basalt) and sedimentary rocks including argillaceous rocks, quartz sandstone, arkose and clayish greywacke, as well as pyroclastic sedimentary rock, covering tuffaceous sandstone. Before undergoing late Paleozoic epidote-amphibolite facies regional metamorphism, these protoliths were formed during the middle-late Permian in an island arc setting within a continental margin collage zone. Combined with the regional tectonic evolution, it can be speculated that the formation and the subsequent metamorphism of the protoliths of the metamorphic rocks from the Wudaogou Group were influenced by the change from subduction to collision of the Paleo-Asian Ocean. Similarities of the rare earth element (REE) patterns and parameters among the metamorphic rocks within the Wudaogou Group, auriferous ores from the Xiaoxi'nancha gold (copper) deposit, and scheelites from the Yangjingou tungsten deposit, together with the favorable metallogenic element contents within the metamorphic rock series, imply that the Wudaogou Group could provide parts of metallic material for the gold and tungsten mineralization in the eastern Yanbian area, as exemplified by the Yangjingou deposit and Xiaoxi'nancha deposit, respectively. Further, the metamorphic sedimentary rocks, especially the metamorphic sandstones, quartz schists and quartz mica schists within the Wudaogou Group, have closer genetic relationships with the Yangjingou tungsten mineralization. However, the specific lithologies within this group which control the gold mineralization are still uncertain, and need further research. © 2015 The Society of Resource Geology.

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