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Geochemical compositions of the Lower Cambrian Niutitang Formation shales in the southeastern Yangtze Platform margin were investigated for provenance, tectonic setting, and depositional environment. The shale samples are characterized by higher abundances of large ion lithophile elements (Cs, Ba, and Pb), lower abundances of high field strength elements (Cr, Sc, and Co) and transition elements (Th, Zr, Hf, Nb, and Ta) relative to average shale. North American shale composition (NASC) -normalized rare earth element (REE) patterns are observed, with negative Ce anomalies, negative Eu anomalies, and positive Y anomalies. The chemical index of alteration (CIA) varies from 68.67–74.93. Alkali and alkaline element contents and CIA values suggest that the source rocks have undergone moderate weathering. The index of compositional variability (ICV), Zr/Sc and Th/Sc ratios vary from 0.53 to 1.07, 5.31 to 8.18 and 0.52–1.02, respectively. ICV values and relationships between Zr/Sc and Th/Sc ratios indicate negligible sedimentary recycling. The Al2O3/TiO2 (14–26) and TiO2/Zr (56–77) ratios imply that the source rocks of the investigated shales had intermediate igneous compositions. However, Cr/V ratios and a La/Th–Hf discrimination diagram suggest that the intermediate compositional signal of the source rocks was derived from a mixture of 75% mafic and 25% felsic igneous rocks rather than intermediate igneous rocks. The major source was the Jiangnan continental island arc with bimodal igneous rocks, lying to the south of the study area, together with a contribution from granites and gneisses uplifted and eroded in the Yangtze Block. Discrimination of tectonic setting using major and trace elements indicates that the source rocks originated in a transitional setting from active continental to passive margin, consistent with the failed intracontinental rift model for the evolution of the South China plate. The Niutitang Formation shales were deposited in a rift basin setting under conditions of anoxic bottom water in a redox-stratified water column, with organic-rich shales prospective for shale-gas production being found in deep-water downslope and basin environments rather than the shallow-water shelf.

The Late Jurassic–Early Cretaceous magmatism at the margin of the South China Block (SCB) provide ideal targets to investigate magma petrogenesis and tectonic evolution of the SCB during th...

：The Zongwulong tectonic belt (ZTB) is located between the northern Qaidam tectonic belt and the south Qilian orogenic belt and contains Late Paleozoic and Early- Middle Triassic strata. Structural features and geochronology of Zongwulong ductile shear zone have key implications for the tectonic property of the ZTB. This study integrated field structure, microscopic structure and 40Ar/39Ar laser probe analysis. The shear zone strikes ~NEE-SWW and dips at a high angle, with a NWW-SEE trending and WE stretching lineation, indicating the shear zone as a thrust- slip shear ductile shear. The asymmetric folds, rotating porphyroclast,structural lens and crenulation cleavage can be seen in the field. Mica fish, S − C fabrics, σ type quartz porphyroclastic and quartz wire drawing structure can also be observed under microscope, indicating that the strike- slip- related ductile deformation and mylonitization occurred under low- grade greenschist facies conditions at temperatures of 300° C − 400° C. The highly deformedmylonite schist yielded 40Ar/39Ar ages (245.8±1.7)Ma and (238.5±2.6)Ma for muscovite and biotite, respectively, indicating that the shear deformation occurred during the Early- Mid Triassic. Combined with comprehensive analysis of regional geology and petrology, the authors hold that the age of ductile shear deformation represents the time of Triassic orogeny in the ZTB. The oroginic activity was probably related to the oblique collision between the South Qilian block and the Oulongbuluke block after the closure of the northermost Paleo-Tethys ocean.

The formation and evolution of an intracontinental basin triggered via the subduction or collision of plates at continental margins can record intracontinental tectonic processes. As a typical intracontinental basin during the Jurassic, the Qaidam Basin in western China records how this extensional basin formed and evolved in response to distant subduction or collisional processes and tectonism caused by stresses transmitted from distant convergent plate margins. The Jurassic evolution of the Qaidam Basin, in terms of basin-filling architecture, sediment dispersal pattern and basin properties, remains speculative; hence, these uncertainties need to be revisited. An integrated study of the stratigraphic succession, conglomerates, U-Pb geochronology, and Hf isotopes of detrital zircons was adopted to elucidate the Jurassic evolutionary process of the Qaidam Basin. The results show that a discrete Jurassic terrestrial succession characterized by alluvial fan, braided stream, braided river delta, and lacustrine deposits developed on the western and northern margins of the Qaidam Basin. The stratigraphic succession, U-Pb age dating, and Hf isotope analysis, along with the reconstructed provenance results, suggest small-scale distribution of Lower Jurassic sediments deposited via autochthonous sedimentation on the western margin of the basin, with material mainly originating from the Altyn Tagh Range. Lower Jurassic sediments in the western segment of the northern basin were shed from the Qilian Range (especially the South Qilian) and Eastern Kunlun Range. And coeval sediments in the eastern segment of the northern basin were originated from the Quanji massif. During the Middle-Late Jurassic, the primary source areas were the Qilian Range and Eastern Kunlun Range, which fed material to the whole basin. The Jurassic sedimentary environment in the Qaidam Basin evolved from a series of small-scale, scattered, and rift-related depressions distributed on the western and northern margins during the Early Jurassic to a larger, extensive, and unified depression occupying the whole basin in the Middle Jurassic. The Altyn Tagh Range rose to a certain extent during the Early Jurassic but lacked large-scale strike-slip tectonism throughout the Jurassic. At that time, the North Qaidam tectonic belt had not yet been uplifted and did not shed material into the basin during the Jurassic. The Qaidam Basin experienced intracontinental extensional tectonism with a northeast-southwest trend throughout the Jurassic in response to far-field effects driven by the sequential northward or northeastward amalgamation of blocks to the southern margin of the Qaidam Block and successive accretion of the Qiangtang Block and Lhasa Block onto the southern Eurasian margin during the Late Triassic−Early Jurassic and Late Jurassic−Early Cretaceous, respectively.

The composition of gas released under vacuum by crushing from the gas shale of Longmaxi Formation in Upper Yangtze Plate, Southern China was systematically investigated in this study. The effect of residual gas release on pore structures was checked using low-pressure nitrogen adsorption techniques. The influence of particle size on the determination of pore structure characteristics was considered. Using the Frenkel-Halsey-Hill method from low-pressure nitrogen adsorption data, the fractal dimensions were identified at relative pressures of 0−0.5 and 0.5−1 as D1 and D2, respectively, and the evolution of fractal features related to gas release was also discussed. The results showed that a variety component of residual gas was released from all shale samples, containing hydrocarbon gas of CH4 (29.58% −92.53%), C2H6 (0.97% −2.89%), C3H8 (0.01% −0.65%), and also some non-hydrocarbon gas such as CO2 (3.54% − 67.09%) and N2 (1.88%−8.07%). The total yield of residual gas was in a range from 6.1 μL/g to 17.0 μL/g related to rock weight. The geochemical and mineralogical analysis suggested that the residual gas yield was positively correlated with quartz (R2=0.5480) content. The residual gas released shale sample has a higher surface area of 17.20−25.03 m2/g and the nitrogen adsorption capacity in a range of 27.32−40.86 ml/g that is relatively higher than the original samples (with 9.22−16.30 m2/g and 10.84−17.55 ml/g). Clearer hysteresis loop was observed for the original shale sample in nitrogen adsorption-desorption isotherms than residual gas released sample. Pore structure analysis showed that the proportions of micro-, meso- and macropores were changed as micropores decreased while meso- and macropores increased. The fractal dimensions D1 were in range from 2.5466 to 2.6117 and D2 from 2.6998 to 2.7119 for the residual gas released shale, which is smaller than the original shale. This factor may indicate that the pore in residual gas released shale was more homogeneous than the original shale. The results indicated that both residual gas and their pore space have few contributions to shale gas production and effective reservoir evaluation. The larger fragments samples of granular rather than powdery smaller than 60 mesh fraction of shale seem to be better for performing effective pore structure analysis to the Longmaxi shale.

Triassic A-type granites in eastern South China Block (SCB) are abundant in the Wuyi–Yunkai tectonic domain and provide an important opportunity to explore the early Mesozoic evolution of continental crust of the SE part of the SCB. We carried out U–Pb zircon dating, Lu–Hf isotope analyses of zircon, and whole-rock geochemical analyses for two granitic plutons, the Guiyantou (GYT) and Luoguyan (LGY) granites, from northwestern Fujian Province. LA–ICP–MS U–Pb zircon analyses yielded ages of 232 ± 4 to 231 ± 7 Ma and 221 ± 5 Ma (Middle-Late Triassic) for the GYT and LGY granites. These two granites belong to metaluminous to weakly peraluminous high K calc-alkaline A-type granite that are enriched in K, Al, light rare earth element and Rb, Th, U, and Pb, and depleted in Nb, Ta, P, and Ti. Their rare earth element patterns are highly fractionated with (La/Yb)N ratios of 2–21 and strong negative Eu anomalies (Eu/Eu* = 0.02–0.31). In situ Hf isotopic analysis of zircon from the GYT and LGY granites yiel...

Constraining the Cenozoic uplift of Tian Shan is important for assessing the impact of the India-Asia collision to Central Asia. Here we estimate the uplift history of the Bogda Shan, northeastern Tian Shan, using a thermo-kinematic model which is constrained by previously reported apatite fission-track thermochronological data. By assuming that the growth of the mountain range propagates towards the basin as a classic critical wedge model, we show that the observed variation in the cooling ages on the mountain flank can be used to provide constraints on the timing and rate of the deformation along a series of south dipping thrust faults, which all root on a low-angle decollement. Inverse modeling confirms previous findings from thermal history models that the Cenozoic uplift in the Bogda Shan initiated during the Paleogene, no later than ~40 Ma. Since the early Miocene (~23 Ma), locus of uplift has expanded to the current southern margin of the Junggar Basin. Our kinematic model of the deformation of the Bogda Shan suggests a temporal stability in the shortening rate of the northeastern Tian Shan over the period of the India-Asia collision during the late Cenozoic.

The geochemical data and geochemical proxies of the Niutitang Formation shales in the Yangtze Platform were investigated for deciphering paleodepositional environment and elucidating paleoenvironment conditions responsible for organic carbon accumulation. Ce anomalies, Eu anomalies and Y anomalies of the Niutitang Formation shales is between 0.39 and 0.92, between 0.65 and 1.03, between 0.97 and 1.71, respectively. The REE patterns of the Niutitang Formation shales show enrichment in HREE relative to LREE with negative Ce anomalies, positive Y anomalies and negative Eu anomalies, indicating of a greater influence of seawater compared to hydrothermal fluids. U, V and Mo are enriched in the shales, and Mo/Al exhibits strong covariation with TOC contents, whereas U/Al and V/Al show weak covariation with TOC contents, indicating that H2S associated with hydrothermal vents is present. Compare with upper Niutitang Formation shales, higher V/(V + Ni), Ni/Co and V/Cr ratios in lower Niutitang Formation shales imply that the lower Niutitang Formation shales are deposited in anoxic conditions. Higher Mo/Al and Ni/Al ratios exist in the lower Niutitang Formation shales relative to the upper Niutitang Formation shales, indicating higher primary productivity during deposition of the lower Niutitang Formation shales. Thus, the variations of primary productivity and preservation of organic matter associated with redox conditions of bottom water lead to greater TOC contents in lower Niutitang Formation shales relative to upper Niutitang Formation shales.

There is an ongoing debate regarding the paleogeographic evolution of the Qaidam Block (37.3 °N/96.4 °E) in northwest China during the late Paleozoic. To provide a reliable constraint on the paleogeographic reconstruction and to determine the relationship with the adjacent area, we performed a paleomagnetic investigation of Early and Late Carboniferous sediments from the Qaidam Block. Stepwise thermal demagnetization successfully isolated high unblocking-temperature characteristic directions from the samples. The tilt-corrected mean direction of the Early Carboniferous sediments is Ds/Is = 298.6°/− 46.4° with α95 = 4.7° and N = 15 sites, corresponding to a paleopole at − 3.2 °N, 147.5 °E with A95 = 4.8°. The Late Carboniferous paleomagnetic direction is Ds/Is = 320.1°/− 46.1° with α95 = 5.3° and N = 8 sites, corresponding to a paleopole at − 15.1 °N, 132.2 °E with A95 = 5.4°. A positive fold test for the Early Carboniferous paleomagnetic directions, and consistency with the Kiaman reversed superchron for the Late Carboniferous paleomagnetic directions, indicates the primary origin of the characteristic remanence of the studied section. The new paleomagnetic results suggest that the Qaidam Block was located at about 27 °N and did not undergo significant N-S movement during the Carboniferous. However, the Qaidam Block experienced a counter-clockwise rotation of about 21° during this period. Comparisons of the paleomagnetic results from the major blocks of Central Asia suggest that the Qaidam Block may have experienced a relatively rapid northward movement and collided with the Tarim Block after the Late Permian. Based on the paleomagnetic poles of the Qaidam Block and adjacent blocks, we present a tentative paleogeographic reconstruction for central Asia during the Early and Late Carboniferous.

The Mesozoic to Cenozoic mountain uplift, exhumation, and deformation of the SW Tianshan Mountains (Kyrgyzstan and Northwest China) offer an important window to understand the intra-continental rej...

The Atebayue Sb deposit is hosted in the Silurian clastics in the South Tianshan Orogen in Kyrgyzstan. The Sb ores appear as veins/veinlets and disseminations, with stibnite being the main ore mineral. Gangue minerals comprise quartz, calcite, and clay minerals. The quartz at Atebayue only contains aqueous fluid inclusions with low homogenization temperature (215–336 °C) and salinity (3.4–6.9 wt.% NaCl equiv.), supporting an epizonogenic hydrothermal origin. The minimum trapping pressures estimated from the NaCl─H2O inclusions are 9–14 MPa, suggesting that the Sb mineralization mainly occurred at a depth of 0.9–1.4 km. Sulphur isotopes (δ34S = −0.4 to 6.2‰) suggest that the host rocks within the Silurian system to be a significant source of ore metals. The ores contain average 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb values of 18.112, 15.547, and 38.064, respectively, and 2-stage model ages of 337–381 Ma, indicating the ores were likely sourced from the Paleozoic strata. Integrating the data obtained from the studies including ore geology, fluid inclusion, and S─Pb isotope geochemistry, we conclude that that the Atebayue Sb deposit is best classified as epizonogenic type formed by the Tarim–Kazakhstan continent–continent collision.

The pore characterization in shale depends on the shale composition, affected by the tectonic deformation. To obtain information about the influence of tectonic deformation on shale pore characteristics, the geochemical, mineralogical, structural and textural properties analysis, porosity and pore structure feature investigations are performed using two sets of shale (deformed shale and undeformed shale) collected from the same shale bed of the Wufeng-Longmaxi Formations (Upper Ordovician-Lower Silurian) of southeast of Sichuan Basin, China. The diagenetic environment and shale composition controls on total porosity and pore structure. Both undeformed and deformed samples have a similar porosity (>1.3%). All-scale pore structure analysis reveals that the pore size distribution of all shale samples is mainly from 0.35 nm to 1.E+5 nm. The surface area of both undeformed and deformed samples were mainly contribution from the micropores (>82%). The geochemical and mineralogical analysis suggested that there was a good correlation between the organic maturity, quartz content and shale deformation. Tectonic stress and structural deformation have an effect on the pore surface area and adsorption capacity of shale. Undeformed shale has a higher surface area and nitrogen adsorption capacity, and the strong deformed shale samples have the lowest surface area and nitrogen adsorption capacity. The total porosity was positively correlated with the micro- and mesopores pore volume for undeformed shale (R2 > 0.85), while the porosity of deformed shale was only related to the macropores pore volume (R2 = 0.77). Experimental analysis showed that all shale samples from the same bed had similar total porosity and pore volume, while the deformed shale had notable higher macropores percentages than undeformed shale. The results indicated that accompanied by tectonic deformation, the porosity, total pore volume and micropores content did not change significantly, while the percentages of pores were changed as macropores increased and mesopores decreased. The proportions of micro-, meso- and macropores were changed by structural deformation. Part of mesopores was disappeared due to compression of the tectonic stress, and macropores were generated due to the development of microcracks.

The Mesozoic northern Yangtze foreland basin system was formed by continental collision between the North China and South China plates along the Mianlue suture. Synorogenic stratigraphic sequences of Late Triassic to Early-Middle Jurassic age were developed in the northern Yangtze foreland basin. The upper Middle Jurassic Shaximiao Formation consists mainly of thick-bedded terrestrial successions that serve as the main body of the basin-filling sequences, suggesting intense tectonism in the peripheral orogeny of the foreland basin. Laser-ICP-MS U-Pb analysis of 254 detrital zircon grains from sandstone samples and several published Lower-Middle Jurassic samples, detrital compositions, petrofacies, and paleocurrent reconstructions in the northern Yangtze foreland basin indicate that discrete source areas included the Qinling-Dabieshan ranges and the Mianlue suture zone to the north, and the South China plate to the south. The stratigraphic succession and sediment provenance of the foreland basin imply that the early Mianlue oceanic basin, magmatic arc, and nonmarine molasse foreland basin during the period of deposition were modified or buried by the subsequent continent-continent collision between the North China-Qinling-Dabieshan plate and the Yangtze plate during the Jurassic, which followed the oblique amalgamation between these plates during the Middle-Late Triassic.

The widespread migmatites in the northwestern part of the Sulu Orogen, China, indicate regional anatexis that is of great significance when discussing the tectonic evolution of this continental orogenic belt. Cathodoluminescence (CL) images, U–Pb ages, and in situ trace element compositions of zircons from four pegmatite veins within these migmatites provide clear evidence for the nature of the post-collisional evolution of the Sulu Orogen. The inherited zircon cores reveal that the protoliths of the migmatites were middle Neoproterozoic magmatic rocks (810–620 Ma) of the South China Block. The protoliths underwent two partial melting events. The mantle domains of the inherited zircons record a Late Triassic (222.0–204.0 Ma) partial melting event that occurred during the exhumation and retrograde metamorphism, after ultrahigh-pressure (UHP) metamorphism. Subsequent newly grown zircons record a Middle–Late Jurassic to Early Cretaceous (164.1–125.5 Ma) anatexis event, indicating that the late Mesozoic anatexis started before ca. 164.1 Ma, reached a peak at ca. 152.1 Ma, and ceased at ca. 125.5 Ma. Combined with previous results of studies on the Sulu orogen, the late Mesozoic anatexis suggested that the thickened crust of the Sulu Orogen had started to become unstable before 164.1 Ma. The duration of ~164.1–137 Ma corresponds to a period of transition in the tectonic regime of the Sulu Orogen, enabling the early high-temperature ductile deformation. After ca. 137 Ma, the tectonic regime was fully transformed into extension and the Sulu Orogen underwent rapid thinning and collapse, thus leading to the late medium–low temperature ductile deformation (137–121 Ma) and laying the foundations for the large-scale magmatic emplacement during the late Early Cretaceous (127–115 Ma). These two partial melting events together promoted the rapid exhumation of the Sulu UHP rocks.

Knowledge of the Mesozoic tectonic evolution of the eastern South China Block (ESCB) plays a crucial role in understanding the formation of the Large Granitic Province and polymetallic mineralization. This review focuses on two controversial issues: (1) which one was the primary controlling factor of the Triassic geodynamic process of the South China Block (SCB), oceanic subduction or intracontinental convergence? (2) what was the subduction style of the Paleo-Pacific plate during the Jurassic–Cretaceous? Based on analyses of regional deformation and published geochronological, petrological, and Nd isotopic data of the magmatic rocks, we reconstruct the Mesozoic tectonic architecture and determined the temporal and spatial evolution of magmatic activities in the ESCB. The analysis of regional deformation shows that two groups of folds, including NE/NNE-trending folds in the Cathaysia Block and NW/NWW-trending folds in the inland, were formed in the Middle–Late Triassic. Subsequently, Middle–Late Jurassic NW–SE compression led to large-scale NE-trending fold-thrust deformation in the SCB, except for roughly S–N extension in the eastern Nanling tectonic belt, which caused the occurrence of the NE-striking dextral-normal oblique faults. Geochronological data indicate that magmatism in the ESCB can be divided into five separate stages: at 250–210 Ma, 210–170 Ma, 170–145 Ma, 145–120 Ma, and 120–85 Ma, respectively. In the first stage, granitic rocks consist mainly of S- and A-type granites, with subordinate I-type granites. These three types of granites were all derived from the partial melting of Proterozoic rocks. In the second stage, the magmatic activities are characterized by mantle-derived magmas in the coastal area, while they are featured by the mixing of predominantly mantle-derived melts with the Neoproterozoic crust in the inland area. In the third stage, widespread I- and A-type granites, which are characterized by the crust-mantle mixing, were formed in the Nanling tectonic belt and adjacent regions in response to the intense extension of lithosphere. In contrast, the development of crust-derived magmas in the Wuyi tectonic belt indicates a relatively weak lithosphere extension. The granitoids of the fourth stage, which are composed of I- and A-type granites, are mainly distributed in two separate areas, the eastern Jiangnan Orogenic Belt and southeastern Guangdong Province. Their petrogenesis is related to the crust-mantle mixing under the extensional setting. The magmatic activities in the last stage propagated eastward and were developed in the coastal area. The intrusive suites comprise major I- and A-type granitoids, and minor gabbroids, which were formed in an enhanced lithospheric extensional setting. Combined with the records of regional deformation, sedimentology, and magmatic evolution, we propose a new tectonic evolution model for the ESCB covering the range of ca. 270 Ma to 85 Ma. This model demonstrates that the ESCB probably experienced a coeval multi-plate convergence during the Triassic, producing an intracontinental deformation belt in the Yangtze Block and an Andean-type retro-arc foreland system in the Cathaysia Block. During the Jurassic–Cretaceous period, the subduction of the Paleo-Pacific plate beneath the SCB triggered crustal thickening, local extension, and large-scale lithospheric extension through the advance, tearing, rollback, and breakoff of the oceanic slab.

This study investigates the stress-strain behavior, failure deformation, and change of gas permeability in shale under compressive stress induced failure. The study is based on triaxial compression of shale from Lower Silurian Longmaxi Formation, South China at different angle of bedding planes. It was found that shale behaves as a brittle materials and exhibits brittle and semi-brittle response to peak strength load at different angles of pre-exist bedding during stress compression. The gas permeability increased after failure deformation for all shale samples. However, samples under vertical and horizontal bedding angles exhibited brittle deformation and significant increase in permeability. While the samples with bedding angles of 30° and 60° showed semi-brittle deformation, and the permeability increased slightly after failure. These results indicate that the pre-existing structure influences the mechanical behavior of shale, which consequently affects its gas permeability. The results of this study are of great significance in shale gas exploration and development in areas of South China which has complex tectonic and pre-existing foliation structures.

In order to constrain the timing and petrogenesis of both the hosting rocks and the inner mafic microgranular enclaves (MMEs) of the Liangnong pluton, SE China, we have performed a series of bulk-rock geochemistry, zircon U–Pb, and Hf isotopic analysis, respectively. Zircon laser ablation–inductively coupled plasma–mass spectrometry U–Pb isotopic analysis yielded ages of 106.3 ± 1.1 Ma for the granodiorite and 103.9 ± 1.6 to 105 ± 1.8 Ma for monzogranite phases within the hosting pluton, as well as an age of 104.7 ± 0.8 Ma for the associated MMEs. The host rocks are metaluminous, have A/CNK values of 0.91–1.09, contain relatively high concentrations of SiO2 and K2O, are enriched in Rb, Th, Ba, Zr, and Hf, are depleted of Sr, P, Ti, Nd, and Ta, contain high concentrations of the rare earth elements (REE) and the light REE, and have moderately negative Eu anomalies (Eu*/Eu = 0.6–0.8). In comparison, the MMEs contain high concentrations of Al2O3, FeO, MgO, and TiO2, are relatively enriched in Ba, U, ...

The widespread Late Devonian–Middle Carboniferous volcanic rocks in the Chinese Western Tianshan provide important constraints on the subduction history of the South Tianshan oceanic lithosphere. Here, we investigate the basalt, basaltic andesite, andesite, trachyandesite, and rhyolite from the Dahalajunshan Formation from Western Tianshan. Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) U–Pb zircon geochronology constrains their age of formation to between 376 and 333 Ma (i.e., Late Devonian–Middle Carboniferous) with distinct variation in space (from west to east) and time (from early to late). Based on geochemical, zircon geochronological, and Sr–Nd isotopic data, we demonstrate that the Dahalajunshan volcanic was generated in a continental arc setting associated with the subduction of the south Tianshan Ocean during Late Devonian to Middle Carboniferous. The volcanic rocks belonging to Dahalajunshan Formation in the northwestern part of the Yili Block suggest that the northward subduction of the south Tianshan Ocean was initiated in the Early Devonian; those in the southern and eastern part of the Yili Block were probably produced by a northward subduction of South Tianshan Ocean during Late Devonian to Middle Carboniferous.

The amount of adsorbed shale gas is a key parameter used in shale gas resource evaluation and target area selection, and it is also an important standard for evaluating the mining value of shale gas. Currently, studies on the correlation between particle size and methane adsorption are controversial. In this study, an isothermal adsorption apparatus, the gravimetric sorption analyzer, is used to test the adsorption capacity of different particle sizes in shale to determine the relationship between the particle size and the adsorption capacity of shale. Thegravimetric method requires fewer parameters and produces better results in terms of accuracy and consistency than methods like the volumetric method. Gravimetric measurements are performed in four steps: a blank measurement, preprocessing, a buoyancy measurement, and adsorption and desorption measurements. Gravimetric measurement is presently considered to be a more scientific and accurate method of measuring the amount of adsorption; however, it is time-consuming and requires a strict measuring technique. A Magnetic Suspension Balance (MSB) is the key to verify the accuracy and consistency of this method. Our results show that adsorption capacity and particle size are correlated, but not a linear correlation, and the adsorptions in particles sieved into 40 - 60 and 60 - 80 meshes tend to be larger. We propose that the maximum adsorption corresponding to the particle size is approximately 250 µm (60 mesh) in the shale gas fracturing.

The late Permian–Triassic granites in southeastern China have important tectonic significance for the evolution of East Asia. A detailed study utilizing zircon U–Pb dating, major and trace element geochemistry, and zircon Hf isotope geochemistry for Dashuang and Jingju granites in Zhejiang Province, South China was performed. LA-ICP-MS zircon U–Pb analyses yielded ages of quartz-monzonite and monzogranite that are 234 ± 3 Ma and 231 ± 3 Ma, respectively, from the Dashuang pluton, while the LA-ICP-MS zircon U–Pb ages of monzogranite and K-feldspar granite from the Jingju pluton are 246 ± 2 Ma and 241 ± 3 Ma, respectively. These ages indicate that the magmatism event took place during the early Triassic to Mid-Triassic. The two granites have high contents of total alkalis (Na 2 O + K 2 O = 7.73–10.24%), high-field-strength elements (e.g., Zr = 215–471 ppm, Y = 25.8–36.5 ppm, Nb = 15–28 ppm, and Zr + Nb + Ce + Y = 293–849 ppm) and rare earth elements (total REE = 299–701 ppm), as well as high Ga/Al ratios (10,000 × Ga/Al = 2.44–2.9). The zircon saturation temperatures were 800–837 °C for the two granites, which suggests that they have the petrographic and geochemical characteristics of A-type granites. In-situ Hf isotopic analyses revealed that the two granites have e Hf ( t ) values ranging from −20 to −6 and two-stage depleted mantle Hf model ages from 1.6 Ga to 2.6 Ga, which indicate that the two granite magmas were formed by the partial melting of Paleoproterozoic crust rocks in the Cathaysia Block. A series of A-type granites distributed in the coastal region probably defines an extensional environment in the early Triassic.

Large-scale volcanism in the late Mesozoic was a prominent geological event in southeast China. The late Mesozoic volcanic sequences, named the Moshishan Group, are exposed in Zhejiang Province and are predominantly felsic in composition with subordinate mafic magma and rare andesites. To understand the late Mesozoic tectonic evolution of southeast China, we present zircon U–Pb dating, major and trace element analyses, and Hf isotopic compositions from felsic volcanic rocks of the Moshishan Group. Zircon U–Pb dating shows that the Moshishan Group formed between 145 and 129 Ma. The eHf(t) of the analysed zircons ranges from −16.58 to +6.89, and the TDM2 age ranges from 753 to 2238 Ma with a major peak at ca. 1870 Ma. Hf isotopic compositions of zircons in Early Cretaceous volcanic rocks are more radiogenic than that of the metamorphic basement rocks, indicating a juvenile component in these magmas. Major element concentrations show that the volcanic rocks mainly belong to the high-K calc-alkaline series. B...

The economic and accurate measurement of micron or submicron size pores in shale is still a challenge. The mercury injection capillary pressure (MICP) measurement of shale particles is an effective method to evaluate the macropore structure, but it is questionable without proper data interpretation. In this study, the fractal theory was applied to identify the four stages of MICP measurement: Stage A is controlled by the interparticle voids in the particle assemblage; Stage B can reflect mercury intrusion into the pores of the shale; and Stage C and D indicate the shale matrix compression and pore structure change induced by high pressure, respectively. Based on the consistent fractal dimension derived from Stage A, the conformance volume induced by interparticle voids at each pressure step in Stage B was quantitatively simulated using the linear fitting method. The correction results show that simultaneous mercury filling of interparticle voids has an important impact on the pore volume in the pore size range larger than 1 μm. To cover the complete pore size range, the MICP data in Stage C and D were substituted by gas adsorption data. The new correction method for MICP data was verified by the good match between the MICP-gas adsorption combined porosity and the helium porosity of the same sample and by the good agreement between the pore size distribution (PSD) curves from the MICP and N2 adsorption measurements in their overlapped pore size range. Therefore, the MICP and gas adsorption methods can be used in conjunction to characterize the pore structure of shale in the complete pore size range. The application of this method is particularly good for the silty samples of lacustrine shale in the study area compared with the clayey samples. To further improve the convergence of different fluid injection methods, more efforts are needed to determine the optimum particle size class and optimum data interpretation model for different shale lithofacies.

Dandruff is an unpleasant scalp disorder common to human populations. In this study, we systematically investigated the intra- and inter-associations among dandruff, physiological conditions such as sebum of the scalp, host demographics such as gender, age and the region of the scalp, and the microorganisms on the scalp. We found that the physiological conditions were highly relevant to the host age and varied in different regions of the same scalp. The sebum quantity and water content were negatively correlated with the formation of dandruff and had significant relationships with the two dominant but reciprocally inhibited bacteria on the scalp (Propionibacterium and Staphylococcus). The dominant fungus (Malassezia species) displayed contrary roles in its contribution to the healthy scalp micro-environment. Bacteria and fungi didn’t show a close association with each other, but the intramembers were tightly linked. Bacteria had a stronger relationship with the severity of dandruff than fungi. Our results indicated that the severity of dandruff was closely associated with the interactions between the host and microorganisms. This study suggests that adjusting the balance of the bacteria on the scalp, particularly by enhancing Propionibacterium and suppressing Staphylococcus, might be a potential solution to lessen dandruff.

The granitic dykes in the Badu Group, Zhejiang Province, South China provide important insights on tectonic setting and crustal evolution of the South China Block (SCB) and the Indochina Block during Triassic. Here we report LA-ICP-MS U–Pb data of granitic rocks from the Hucun and Kengkou which show early Triassic ages of 242 ± 2 and 232 ± 3 Ma, respectively, representing their timing of emplacement. The dyke rocks are enriched in K, Al, LREE, Rb, Th, U, and Pb, and are depleted in Nb, Ta, Sr, and Ti. The rocks are characterized by highly fractionated REE patterns with (La/Yb) N ratios of 28.46–38.07 with strong negative Eu anomalies (Eu/Eu* = 0.65–0.73). In situ Hf isotopic analyses of zircons from the Hucun granite yielded ɛ Hf ( t ) values of −13.9 to −6.4 and two-stage depleted mantle Hf model ages of 1.68–2.15 Ga, which indicate that the magma was formed by partial melting of the Paleoproterozoic metasedimentary protoliths in the Cathaysia Block. The zircons from the Kengkou granite have ɛ Hf ( t ) values ranging from −40.7 to 31.5 and yield two-stage depleted mantle Hf model ages of 0.99–2.49 Ga, indicating magma origin from a mixed source. The Hucun and Kengkou dykes, together with the Triassic A-type granites in SE China were probably generated during magmatism associated with crust–mantle decoupling along the convergent plate boundary between SCB and the Indochina Block.

A serial of “comb-like and trough-like” folds developed in eastern Sichuan, controlled by the multi-layer detachment folding, is different from the classical Jura-type structure in their development. The key factor resulting in the development of these structures is the occurrence of detachment layers in different parts of Neoprotozoic to Mesozoic stratigraphy of study area, which, from the bottom to the top, are the lower part of Banxi Group, Lower Cambrian (Niutitang Formation), Lower Silurian (Longmaxi Formation and Luoreping Formation), Upper Permian (Wujiaping Formation) and Lower Triassic (Daye Formation). On the basis of field survey combined with sand-box modeling, this study argued that the detachment layer of the lower part of Banxi Group controlled the development of the “comb-like” folds, and the lower part of Cambrian detachment layer controlled the development of “trough-like” folds. Because of several detachment layers occurring in the study area, the development of duplex structures different scales is an important deformation mechanism, and the duplexes are the important structures distinguished from the typical detachment folding structures. Due to these duplexes, the surface structures and structural highs may not be the structural highs in the depth. Meanwhile, the detachment layers are good channels for oil/gas migration benefiting the understanding of accumulation and migration of oil and gas.

The Tianshan Mountains have undergone its initial orogeny, extension adjusting and re-orogeny since the Late Paleozoic. The re-orogeny and uplifting process of the orogeny in the Mesozoic and Cenozoic are two of most important events in the geological evolution of Euro-Asian continent, which resulted in the formation of the present range-and-basin pattern in topography of the Tianshan Mountains and its adjacent areas. Thermochronology results by the method of fission-track dating of apatite suggest three obvious uplifting stages of the Bogad Mountain Chain re-orogeny during the Cenozoic, i.e. 5.6–19 Ma, 20–30 Ma, and 42–47 Ma. The strongest uplifting stage of the mountain is the second one at 20–30 Ma, when the mountain uplifted as a whole, and the beginning of re-orogeny was no less than 65 Ma. Furthermore, our studies also show that the uplifting types of the mountain are variable in the different time periods, including uplifting of mountain as a whole and differential uplifting. The apparently diversified uplifting processes of the mountain chain are characterized by the migration (or transformation) of the uplifting direction of the mountain from west to east and from north to south, and the main process of mountain extending is from north to south.

The changes of trend and character of the gravity anomaly map can be used to interpret the fault distribution. The gravity anomaly map of east Zhejiang province had been decomposed by means of wavelet analysis. The wavelet details maps show that the faults can be divided into 3 levels from the aspects of scale and depth. The 1st level faults are NE-SW directional faults, which have big extension length and depth. Most of them have outcropped. The 2nd level faults are NW-SE directional faults, which have small depth, some of them have outcropped, but most of them are concealed, and cut the NW-SE faults. The 3rd level faults are approximately S-N directional faults. Those are concealed and covered by NW-SE faults, so they formed earlier than NW-SE faults. In the southern section, there is a big granite, which forked toward the ground, and scattered on the earth's surface. The results above demonstrated that the information of different objective density resources can be extracted effectively from the gravity anomaly map through wavelet analysis. Keywords—Digital image processing; Gravity anomaly map; Wavelet analysis; Zhejiang province; Information extraction

Huge diabase occurs within the Proterozoic strata in the southern margin of the North China Block, geographically in the northern parts of Anhui and Jiangsu provinces, where no strata younger than Neoproterozoic have been found. Zircons from the diabase show three different structures from cathodoluminesecence imaging, but they are all of magmatic origin. SHRIMP U-Pb dating yields a range of 206Pb/238U ages from 2600 to 124 Ma, but two geological events can clearly be identified from both concordant and discordant ages. One gives two weighted mean 207Pb/206Pb ages of 976 ± 24 and 1038 ± 26 Ma which are interpreted as timing of diabase crystallization, and the other has a weighted mean 207Pb/206Pb age of 2523 ± 52 Ma that represents formation time of inherited zircon from the old crust. The dating results indicate that the mafic magmatic event occurred in a transition period from the latest Mesoproterozoic to the earliest Neoproterozoic, consistent with global subduction of Grenvill ocean crust to result in the assembly of supercontinent Rodinia. Therefore, the North China Block needs to be taken into account when reconstructing the position of China continents within the framework of Rodinia supercontinent.

According to the field occurrences and petrological study, the low temperature eclogite facies metamorphic rocks in Western Tianshan of Xinjiang can be divided into five types: (i) massive glaucophane-epidote eclogites and glaucophane-paragonite eclogites; (ii) schistose or gneissic mica eclogites; (iii) banded calcite eclogites; (iv) pillow glaucophane eclogites; (v) garnet-omphacite quartzites. Their eclogite facies metamorphism has undergone four stages of evolution: (i) pre-peak lawsonite-blueschist facies stage, T = 350—4000℃, P = 0.7—0.9 GPa; (ii) peak eclogite facies stage, T = 530 ± 20℃, P = 1.6—1.9 GPa; (iii) retrograde epidote-blueschist facies stage, T =500—530℃, P = 0.9—1.2 GPa and (iv) retrograde blueschist-greenschist facies stage, T = 450—550℃, P = 0.7—0.8 GPa. The metamorphic PT path of Western Tianshan eclogites is characterized by clockwise ITD resulting from the subduction of Tarim plate northward to Yili-Central Tianshan plate followed by fast uplift to the surface. But there were at least two stages of blueschist facies retrograde metamorphism overprinted during their uplift.