► Magmatic spatial–temporal evolution. ► Neoproterozoic, Paleozoic, Early Mesozoic and Late Mesozoic four magmatism periods. ► Experienced three-stage orogenic processes in Qinling Orogen.
The ...Qinling Orogen is one of the main orogenic belts in Asia and is characterized by multi-stage orogenic processes and the development of voluminous magmatic intrusions. The results of zircon U–Pb dating indicate that granitoid magmatism in the Qinling Orogen mainly occurred in four distinct periods: the Neoproterozoic (979–711Ma), Paleozoic (507–400Ma), and Early (252–185Ma) and Late (158–100Ma) Mesozoic. The Neoproterozoic granitic magmatism in the Qinling Orogen is represented by strongly deformed S-type granites emplaced at 979–911Ma, weakly deformed I-type granites at 894–815Ma, and A-type granites at 759–711Ma. They can be interpreted as the products of respectively syn-collisional, post-collisional and extensional setting, in response to the assembly and breakup of the Rodinia supercontinent. The Paleozoic magmatism can be temporally classified into three stages of 507–470Ma, 460–422Ma and ∼415–400Ma. They were genetically related to the subduction of the Shangdan Ocean and subsequent collision of the southern North China Block and the South Qinling Belt. The 507–470Ma magmatism is spatially and temporally related to ultrahigh-pressure metamorphism in the studied area. The 460–422Ma magmatism with an extensive development in the North Qinling Belt is characterized by I-type granitoids and originated from the lower crust with the involvement of mantle-derived magma in a collisional setting. The magmatism with the formation age of ∼415–400Ma only occurred in the middle part of the North Qinling Belt and is dominated by I-type granitoid intrusions, and probably formed in the late-stage of a collisional setting. Early Mesozoic magmatism in the study area occurred between 252 and 185Ma, with the cluster in 225–200Ma. It took place predominantly in the western part of the South Qinling Belt. The 250–240Ma I-type granitoids are of small volume and show high Sr/Y ratios, and may have been formed in a continental arc setting related to subduction of the Mianlue Ocean between the South Qinling Belt and the South China Block. Voluminous late-stage (225–185Ma) magmatism evolved from early I-type to later I-A-type granitoids associated with contemporaneous lamprophyres, representative of a transition from syn- to post-collisional setting in response to the collision between the North China and the South China blocks. Late Mesozoic (158–100Ma) granitoids, located in the southern margin of the North China Block and the eastern part of the North Qinling Belt, are characterized by I-type, I- to A-type, and A-type granitoids that were emplaced in a post-orogenic or intraplate setting. The first three of the four periods of magmatism were associated with three important orogenic processes and the last one with intracontinental process. These suggest that the tectonic evolution of the Qinling Orogen is very complicated.
The Qinling orogen is a typical composite orogen for understanding multi-stages of magmatism and orogenic processes. Many studies have been carried out on the magmatic rocks in the Qinling orogen but ...their petrogenesis is still controversial. This pa- per presents a review of all granitoid rocks based on previous and new studies of geochronology and geochemistry. Four dis- tinct periods of granitoid magmatism, Neoproterozoic （979-711 Ma）, Paleozoic （507-400 Ma）, Early Mesozoic （250-185 Ma） and Late Mesozoic （160-100 Ma）, have been recognized from the Qinling orogen according to zircon U-Pb ages, intrusion as- sociations and deformation, as well as regional geology. The Neoproterozoic granitic rocks consist of three stages at 979-911, 894-815 and 759-711 Ma, respectively, corresponding to strongly deformed S-type, weakly deformed I-type and A-type gran- itoids. They can be interpreted as magmatic occurrences in syn-collisional, post-collisional and extensional settings, respec- tively, in response to old continental terranes of the Neoproterozoic tectonomagmatic events in the old continents of China, such as South China and Tarim cratons. Although this continental terrane would be involved in the Phanerozoic Qinling orog- eny, the Neoproterozoic magmatic rocks are not the products of the Qinling orogenic processes. The Paleozoic magmatic rocks can be classified into three stages at 507-470, 460-422 and 415-400 Ma, respectively. The first-stage magmatism is temporal- ly associated with ultra-high pressure metamorphism in the North Qinling terrane. These magmatic rocks are interpreted as magmatic occurrences in subductional, syn-collisional and post-collisional settings, respectively. The Early Mesozoic mag- matic rocks occur in two stages at 252-185 and 225-200 Ma, respectively. The first-stage granitoids are mainly represented by I-type quartz diorites and granodiorites, and the second stage by granodiorites and monzogranites with the 1- to A-type charac- teristics and some with rapakivi textures. Their emplacement ages and geochemical parameters such as A/CNK, K2O/Na2O ra- tios and εNd（t） values do not show any polarity change in perpendicular to subduction/collision zone. Therefore, all these Early Mesozoic granitoids are unlikely the product of continental subduction as some researchers suggested. Instead, they are plausi- bly related to the subduction of the Mianlue Ocean and the subsequent collision between the South China Craton and the South Qinling terrane. The Late Mesozoic granitoids were emplaced mainly at two stages of 160-130 and 120-100 Ma, and charac- terized by the evolution from I- to I-A- and A-type granitoids. These characteristics are consistent with the granitoid magmatic evolution from contractional to extensional settings during the Jurassic/Cretaceous in eastern China. Accordingly, the Late Mesozoic granitoid rocks in the Qinling orogen probably have a similar petrogenetic mechanism to those of the huge magmatic belt along the western Pacific margin, i.e., intra-continent magmatism related to a far-field effect of the subduction of Paleo-Pacific plate.
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•The sandstones overlying the OB were deposited after 1.7 Ga.•The OB is an ancient block with some Paleoarchean crust materials.•Predominant crust growth in the OB occurred at early ...Neoarchean.•2.5–2.4 Ga, 2.2–2.0 Ga, and 1.95–1.8 Ga events were recorded in the OB.
The Ordos Block (OB) is generally considered to be an important micro-block concerning the early geological evolution of the North China Craton (NCC). Previous geophysical and limited geological researches for the OB basement have provided a preliminary understanding of the lithological assemblages and geological structure of the basement, but little was discussed about its formation time and early Precambrian evolution. In this contribution, to better understand the formation and evolution of the OB basement, the new LA-ICP-MS U-Pb ages, Lu-Hf isotope, and trace element composition have been carried for the detrital zircons from the sandstones of the Changcheng System overlying the OB basement. The youngest concordant U-Pb age constrains the Changcheng System to be deposited after ∼1.7 Ga, consistent with the Changcheng System in the other regions of the NCC. The 3.6–3.3 Ga detrital zircons preserved in the sandstones from the Changcheng System, associated with the 3.4 Ga inherited zircon in basement rocks, indicate the potential presence of Paleoarchean crustal materials in the OB. The 2.8–2.6 Ga zircons with positive εHf(t) values (+0.6 to +6.4) have the two-stage model ages (TDMC = 3.23–2.75 Ga) close to their formation ages, combined with the crustal thickening during this period, suggesting a major crustal growth in the early Neoarchean. In addition, the main age clusters of the 2.5–2.4 Ga, 2.2–2.0 Ga, and 1.95–1.8 Ga yield εHf(t) values of −6.9 to +7.7 with TDMC of 3.39–2.47 Ga, −13.4 to +7.5 with TDMC of 3.49–2.19 Ga, and −14.0 to +2.2 with TDMC of 3.41–2.40 Ga, respectively, indicative of three main stages of crustal reworking associated with two stage of minor juvenile crustal growth around 2.5–2.4 Ga and 2.2–2.0 Ga. They were corresponding to partial melting of the continental crust in the late Neoarchean, magmatism resulting from the plate subduction in the mid-Paleoproterozoic, and the collision and amalgamation between eastern and western blocks in the late Paleoproterozoic, respectively. All demonstrate that the OB was an ancient block formed mainly in the early Neoarchean and then subjected to three strong tectonothermal events of 2.5–2.4 Ga, 2.2–2.0 Ga, and 1.95–1.8 Ga, which occurred in the peripheral orogenic belts.
The North Qinling orogenic belt is an important component of Qinling composite orogen in Central China. High-pressure and ultra-high pressure (HP-UHP) rocks occur as lenses or layers surrounded by ...gneissic rocks in the northern, central, and southern Qinling Complex of the North Qinling belt, considered to have formed through deep continental subduction. The magmatic protoliths of the HP-UHP metamorphic rocks show formation ages (ca. 800Ma), geochemical characteristics, and Pb-Nd isotopic compositions similar to those of the Neoproterozoic igneous rocks of the South Qinling belt. Continental materials of the South Qinling belt were dragged down to mantle depths by the Shangdan oceanic crust subducted and subjected to HP-UHP metamorphism at ca. 500Ma. The Erlangping (and Kuanping) backarc basin formed in response to subduction of the Shangdan ocean and might have developed into a limited small ocean basin at ca. 500Ma.
The HP-UHP rocks yielded retrograde metamorphic ages of ca. 470–450Ma and ca. 420–400Ma. These ages are identical to the age of magmatic events in the North Qinling HP-UHP belt at ~500Ma, ~450Ma and ~420Ma, related to deep subduction/collision, slab-breakoff and crustal thinning during post-collisional extension. The dominant ca. 500–400Ma ages of detrital zircons from the Liuling Group of the South Qinling belt match well with those from the three stages of magmatic rocks and HP-UHP rocks in the Qinling Complex. This correlation suggests that the magmatic rocks and HP-UHP metamorphic rocks in the North Qinling belt initially exhumed to the surface, eroded and were then deposited in the Liuling basin in a post-orogenic extensional setting during middle to late Devonian.
New evidence suggests that the Qinling Complex is a tectonic complex rather than a uniform stratigraphic unit or a microcontinent as previously believed, and is mainly composed of the exhumed HP-UHP metamorphic rocks, deep subduction- exhumation-related magmatic rocks and the early Neoproterozoic granites together with the host rocks from the over-riding plate at an active continental margin. The early Paleozoic tectonic history of the NQB includes oceanic slab subduction and formation of arc, backarc spreading, continental deep subduction, arc-continent collision, break off, and multi-stage exhumation of the deep subducted slab, as well as extension and thinning and associated erosion and deposition.
•The late-Paleoproterozoic granites in Lüliang Complex show a transition from high-K I-type to A-type granites.•The 1.89–1.76 Ga granites were formed under a post-collisional setting.•The occurrence ...of A2-type granites indicate a crustal thinning in the extensional setting after 1.82 Ga.
The late-Paleoproterozoic granitoids from Lüliang Complex can provide pivotal constraints on the amalgamation process between Eastern and Western blocks of North China Craton along the Trans-North China Orogen. LA-ICP-MS zircon dating gives emplacement ages of 1854 ± 20 Ma for the Huijiazhuang granite, 1830 ± 21 Ma for the Xiyupi granite vein and 1760 ± 20 Ma for the Dacaoping porphyritic granite, respectively. The Huijiazhuang granite and Xiyupi granite dyke have variable SiO2 (66.71–74.31 wt%), high K2O (5.09–6.35 wt%), low P2O5 (0.02–0.16 wt%), Al2O3 (13.92–15.31 wt%), right inclined REE patterns with medium negative Eu anomalies, enrichment in LILE, depletion in HFSE, especially Nb, Ta, consisting to high-K I-type granite in a post-collisional setting. The Sr/Y (7.36–59.95), εNd(t) (−5.7 to −4.1) with TDM (2381 Ma to 2570 Ma) from whole rock Sm-Nd isotope and εHf(t) (−9.6 to 2.3) with TCDM (2360 Ma to 3070 Ma) from zircon Lu-Hf isotope suggest that they are produced by partial melting of slightly thickened Neoarchean-Paleoproterozoic basement materials (including both meta-sedimentary and meta-igneous rocks). The Dacaoping porphyritic granites are characterized by high SiO2 (70.83–74.30 wt%), K2O (4.84–5.60 wt%), FeOT/(FeOT + MgO) (0.86–0.92), “seagull-type” REE pattern with strong negative Eu anomaly (δEu=0.16–0.35) and higher 10000∗Ga/Al (2.99–3.36), HFSE (Zr + Nb + Ce + Y = 378–583 ppm), showing an affinity of A2-type granite. They have low Sr/Y (1.17–8.62), εNd(t) (-6.1 to -6.4) with TDM (2690 Ma to 2776 Ma) from whole rock Sm-Nd isotope and εHf(t) (-7.9 to -5.2) with TCDM (2775–2938 Ma) from zircon Lu-Hf isotope, indicating a result from the melting of thinned Neoarchean calc-alkaline intermediate basement. Taking into account the temporal-spatial distributions of late-Paleoproterozoic rocks in the Trans-North China Orogen, it suggests a post-collisional extension occurred during 1.89–1.76 Ga and the crustis thinnedvisibly since 1.82 Ga.
Systematical analyses of data from GEOROC and PetDB database show that large amount of Cenozoic andesites occurred in the various oceanic environments such as mid-oceanic ridge, plume-related island ...and oceanic arc. In this study, we employed the geochemical data of 351 mid-ocean ridge andesites (MORA), 2 539 plume-related andesites (PRA) and 3 488 oceanic arc andesites (OAA) from the database to discuss the relationship between andesite tectonic settings and their geochemical features, thereby making an attempt to construct tectonic discrimination diagrams. Based on the data-driven pattern, all available elements were employed to derive logratios for the possible coordinates, and the overlap-rate calculation was adopted to evaluate the discrimination effect of more than 330 000 prospective diagrams. Finally, four tectonic discrimination diagrams have been successfully established to identify MORA, PRA and OAA, which can be utilized to identify the original settings of andesite with an age range from Cenozoic to Archean a certain extent. Of these diagrams, PRA is mainly distinguished by high LREE/HREE ratio due to enriched mantle source. Whereas, OAA is mainly characterized by high LILE/HFSE ratio, which reveals that fluids derived from subducted slab play an important role in forming oceanic arc andesites. Consequently, the petrogenesis of andesites is closely related to their tectonic settings. However, it should be noted that those andesites formed in both continental and oceanic environments cannot be effectively distinguished using these diagrams. We strongly recommend integrating the discrimination diagrams result with other geological information to reach a comprehensive interpretation of evolution history with those ancient andesites. This paper presents a case study which suggests that data-driven method is a powerful tool for solving geological problems in this ‘big data” era.
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•Ca-doped Li4Ti5O12 samples were prepared by a simple solid-state method.•The high-rate performance of Li4−xCaxTi5O12 (0≤x≤0.2) anode was first reported.•Li3.9Ca0.1Ti5O12 shows the ...best high-rate performance.
Ca-doped lithium titanates with the formula of Li4−xCaxTi5O12 (x=0, 0.05, 0.1, 0.15, 0.2) were synthesized as anode materials by a simple solid-state reaction in an air atmosphere. The phase structure, morphologies and electrochemical properties of the prepared powders were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic voltammetry (CV), respectively. XRD revealed that the Ca-doping caused no change on the phase structure and highly crystalline Li4−xCaxTi5O12 (0≤x≤0.2) powders without any impurity were obtained. SEM images showed that all samples had similar particulate morphologies and the particle size distribution was in the range of 1–2μm. It was observed that Ca-doped lithium titanates employed as the anode materials of lithium-ion batteries delivered excellent electrochemical performances, and sample Li3.9Ca0.1Ti5O12 exhibited a higher specific capacity, better cycling performance and rate capability than other samples. The Li3.9Ca0.1Ti5O12 material showed discharge capacities of 162.4mAhg−1, 148.8mAhg−1 and 138.7mAhg−1 after 100 cycles at 1C, 5C and 10C charge–discharge rates, respectively. Electrochemical impedance spectroscopy (EIS) revealed that the Li3.9Ca0.1Ti5O12 electrode exhibited the highest electronic conductivity and fastest lithium-ion diffusivity, which indicated that this novel Li3.9Ca0.1Ti5O12 material was promising as a high-rate anode material for the lithium-ion batteries.
•W-doped Li4Ti5O12 samples were prepared by a sol–gel method.•The high-rate performance of Li4Ti5−xWxO12 (0≤x≤0.2) anode was fully investigated.•Li4Ti4.9W0.1O12 shows the best high-rate performance.
...W-doped Li4Ti5O12 (LTO) in the form of Li4Ti5−xWxO12 (x=0.05, 0.1, 0.15 and 0.2) is prepared by sol–gel method and following two-step calcinations in the air and argon atmosphere, respectively. The as-prepared samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). XRD analysis demonstrates that W6+ can successfully enter the structure of cubic spinel-type LTO, increase the lattice parameter and no impurities appear. XPS results further identify the existence of W6+ ion. SEM images show that all samples had similar particulate morphologies and the particle size distribution was in the range of 0.5–1μm. The results of electrochemical measurement reveal that W-doping can improve the rate capability of LTO. However, heavy W substitution causes a discharge capability loss. The electronic conductivity of Li4Ti4.9W0.1O12 powder is as high as 1.5×10−1Scm−1, which is much higher than 10−13Scm−1 of the pristine LTO. The Li4Ti4.9W0.1O12 electrode exhibits the best rate capability and cycling stability, and its discharge capacity at 10C is 128.1mAhg−1 after 100 cycles. The Li4Ti4.9W0.1O12 sample stands as a promising potentially high rate anode material for lithium-ion batteries.
The moisture and thermal characteristics of expansive soil slopes have a significant impact on the strength and overall stability of the soil. In this study, the medium-strength expansive soil ...vegetated slope in Baise, Guangxi, was taken as the research object. Through the combination of numerical simulation and measured meteorological data, the impact of moisture and heat characteristics on slope stability was then analyzed, and optimal geometric parameters conducive to the stability of vegetated slopes were proposed based on these findings. The research results indicate that under long-term climatic conditions, solar net radiation has the most sensitive effect on the evaporation of slope soil. During the evaporation process, vegetation transpiration dominates in the vegetation-covered layer, while below the depth of the vegetation cover layer, soil evaporation itself plays a dominant role. Under the conditions of evaporation-rainfall-evaporation, slopes with a smaller permeability coefficient in the vegetation cover layer have significantly higher safety factors than slopes with a larger permeability coefficient and bare slopes. A steep vegetated slope with a slope gradient of 50° can maintain slope stability with proper handling of its height. The research findings have reference value for the design and construction of vegetated slopes with expansive soil.
Tumor mutation burden (TMB) level is identified as a useful predictor in multiple tumors including colon adenocarcinoma (COAD). However, the function of TMB related genes has not been explored ...previously. In this study, we obtained patients' expression and clinical data from The Cancer Genome Atlas (TCGA) and the National Center for Biotechnology Information (NCBI). TMB genes were screened and subjected to differential expression analysis. Univariate Cox and LASSO analyses were utilized to construct the prognostic signature. The efficiency of the signature was tested by using a receiver operating characteristic (ROC) curve. A nomogram was further plotted to assess the overall survival (OS) time of patients with COAD. In addition, we compared the predictive performance of our signature with other four published signatures. Functional analyses indicated that patients in the low-risk group have obviously different enrichment of tumor related pathways and tumor infiltrating immune cells from that of high-risk patients. Our findings suggested that the ten genes' prognostic signature could exert undeniable prognostic functions in patients with COAD, which might provide significant clues for the development of personalized management of these patients.
