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In the last 2 years, rubber tree abnormal leaf fall occurred over large area in Xishuangbanna rubber plantation, and the symptoms were similar to those of rubber tree Phytophthora leaf fall disease. In order to clarify the pathogenic species and screen fungicides for effective control of this disease, the pathogen was isolated and purified by tissue isolation and mycelia cusp purification method, and the pathogenicity was determined by Koch' s postulates test, morphological and physiological characteristics, rDNA-ITS and COX II gene sequence analysis. The results showed that the pathogen caused rubber tree abnormal leaf fall was identified as Phytophthora botryosa, which was a new record pathogen of rubber tree Phytophthora leaf fall disease in China. The antibiotic activities of 15 fungicides was tested in vitro with mycelial growth rate method. 48% dimethomorph-cyazofamid SC (suspension concentrate), 80% dimethomorph WG (water dispersible granule), 30% metalaxyl-dimethomorph WG, 35% dimethomorph-cymoxanil SC, 30% floridomide-metalaxyl WG and 0.3% tetramycin AS (aqueoces solution) could effectively inhibit the mycelial growth of the pathogen, with EC50 of 0.137 1, 0.175 9, 0.201 7, 0.2577, 0.265 1, 0.351 0 mg⋅L-1, respectively, which could be used as candidates for control of the disease in the field. [ABSTRACT FROM AUTHOR]

Based on the collation and collection of a large number of data, we construct an induced earthquake database, QuakeQuake, and report a total of 193 human‐induced earthquake cases in China. 155 human‐induced earthquakes in China recorded in the global‐induced earthquake database (HiQuake) are revisited and re‐arranged by compiling the Chinese literature. The human‐induced earthquakes in QuakeQuake database are classified into three levels of reliability, strong, moderate and weak levels, based on both human‐induced processes and seismic activity. Three main categories including reservoir‐induced earthquakes, mine‐induced earthquakes and other induced earthquakes in China are sorted based on data recording and types of the induced earthquakes. Most of the induced earthquakes with strong level in QuakeQuake database are mainly minor earthquakes (3 ≤ M < 4.5). The focal depth of reservoir‐induced and mining‐induced earthquakes is within 30 and 8 km deep, respectively. The active type of source faults of the large induced earthquakes is mainly thrust type with the highest proportion. The largest observed magnitude of the induced earthquakes (MMAX) correlates positively with the injection/extraction volume, reservoir dam heights, reservoir capacity and lithology of the reservoir area. Nine volume intervals corresponding to each induced earthquake type are figured out. Based on the analysis of the mechanisms of human‐induced earthquakes in China, the main mechanisms of surface mass loading are karst collapse or gas explosion, pore water pressure effect and gravity energy release. Underground material extraction is mainly induced by the compaction of different reservoirs. Two injection types of underground material are gas injection and water injection. Gas injection is related to continuous stress loading and unloading. Two induction mechanisms of water injection are the increase of fault pore pressure and the change of fault load condition. [ABSTRACT FROM AUTHOR]

The northern South China Sea continental margin is the key or critical segment of the Ocean-Continent Connection Zone (OCCZ) of the Great South China Block' the junction between the Tethyan and the (Paleo-) Pacific dynamic systems' and the interaction area between the Indian Ocean and the Pacific Ocean. However' due to the low-degree geophysical exploration in the past' the regional tectonic background' processes and mechanism of the transition between the Tethyan and the Pacific tectonic domains are unclear. Based on the latest large number of seismic profiles' we focus on the Cenozoic basin structure in the continental margin of the northern South China Sea and try to reveal the Mesozoic basement structures of the northern South China Sea continental margin, with the aim of exploring the pre-Cenozoic tectonic evolution and the Cenozoic opening, spreading, ridge fossil and closure of the South China Sea oceanic basin, so as to serve the accurate oil and gas exploration in this area at the same time. The seismic interpretation of the Pearl River Mouth Basin and the field structural investigation of the South China continental margin show that the OCCZ of the South China Block has experienced three processes: Mesozoic Indosinian collisional orogeny, Early Yanshanian accretionary orogeny and Late Yanshanian transpressive orogeny. During the Cenozoic era, it experienced the dispersive extension into basins under the control of NW-SE-directed normal extension in the early stage, the dextral pull-apart into basins under the control of NE-NNE-trending strike-slip faults in the middle stage, and the sinistral pull-apart into basins under the control of NW-WNW strike-slip faults in the late stage. In general, the transition process from the Tethyan to the Pacific tectonic systems can be subdivided into four stages: the transition from the Paleo-Tethyan to the Neo-Tethyan tectonic systems, the transition from the Neo-Tethyan to the Paleo-Pacific tectonic systems, the transition from the Neo-Tethyan to the Pacific tectonic systems, and the transition from the Paleo-Pacific to the Pacific tectonic systems. The tectonic transition of the East Asian OCCZ reflects the long-term mechanism of the Earth plate dynamic system driving the plate superconvergence in East Asia, in particular of the importance of the deep or submarine "Triple Poles", the Southeast Asian U-shape subduction system, the Pacific LLSVP and the African LLSVP. More importantly, the Southeast Asian U-shape subduction system is also one of the important dynamic engines of the Earth plate motion. [ABSTRACT FROM AUTHOR]

The stress field of the Central North China Block (CNCB) has been affected by the interaction among the Indian, Eurasian and Pacific Ocean plates, and the effect is manifested by the occurrence of large earthquakes in this region. Here, using numerical simulation of the finite element method, attempts were made to evaluate ESE-directed compression on three tectonic zones, namely, the Shanxi Graben Zone, the Zhangjiakou-Penglai Fault Zone and the Taihangshan Fault Zone. In these zones, the structural geometry and viscoelastic property of the model were determined, as well as 49 main faults identified, by means of a comprehensive structural analysis of seismic profiles, gravity data and tomography. This study shows that the stress concentration areas in the three zones are all located in the transition zone between NE-trending and NW-trending faults. Numerical simulation analysis of the Xingtai and Tangshan earthquakes revealed that the NE- and NW-trending faults had played an important role in controlling the distribution of the stress field, triggering aftershocks and/or stopping stress propagation during earthquakes. The differences of the stress fields and earthquake distributions among the three tectonic zones resulted from not only the fault combination patterns, but also the geometry of the main faults. [ABSTRACT FROM AUTHOR]

In this study, an inexact fractional programming method is employed for planning the regional-scale water-energy-food nexus (WEFN) system. The IFP cannot only deal with uncertainties expressed as interval parameters, but also handle conflicts among multiple decision stakeholders. The IFP approach is then applied to planning the WEFN system of Henan Province, China. An IFP-WEFN model has been established under consideration of various restrictions related to water and energy availability, as well as food demand. Solutions of the planting areas for different crops in different periods have been generated. The results suggested that there would be a significant increase for vegetable cultivation with an increasing rate of 24.4% and 30% respectively for the conservative and advantageous conditions, followed by the fruit cultivation. In comparison, the planting area of cotton would be decreased with a decreasing rate of 21.2%, and there would also be an explicit decrease for rice cultivation. These results can help generate a desired planting scheme in order to achieve a maximized unit benefit with respect to the water utilization. Comparison between the IFP-WEFN model and the ILP-WEFN model indicates that, even though a slightly lower benefit is obtained from IFP-WENF model, it can result in a higher unit benefit than the planting scheme from ILP-WEFN model. Consequently, the IFP-WEFN model can help decision-makers identify the sustainable agricultural water resources management schemes with a priority of water utilization efficiency. [Display omitted] • IFP method is used to tackle uncertainties and contradictory aims in WEFN systems. • IFP-WEFN model is developed for Henan considering water utilization efficiency. • The results can support sustainable WEFN management with limit water resources. [ABSTRACT FROM AUTHOR]

Abstract: The Trans-North China Orogen separates the North China Craton into two small continental blocks: the Eastern and Western Blocks. As one of the largest exposure in the central part of the orogen, the Hengshan–Wutai–Fuping Complexes consist of four lithotectonic units: the Wutai, Hengshan and Fuping Complexes and the Hutuo Group. The Hengshan Complex contains high pressure mafic granulites and retrograded eclogites. Structural analysis indicates that most of the rocks in these complexes underwent three distinct episodes of folding (D1 to D3) and two stages of ductile thrust shearing (STZ1 between D1 and D2 and STZ2 after D3). The D1 deformation formed penetrative axial planar foliations (S1), mineral stretching lineations (L1), and rarely-preserved small isoclinal folds (F1) in the Hengshan and Fuping Complexes. In the Wutai Complex, however, large-scale F1 recumbent folds with SW-vergence are displayed by sedimentary compositional layers. Penetrative transposition resulted in stacking of thrust sheets which are separated by ductile shear zones (STZ1). The kinematic indicators of STZ1 in the Hengshan and Wutai Complexes show top-to-the-S230°W thrusting likely related to northeastward, oblique pre-collisional subduction. D1 resulted in crustal thickening with resultant prograde peak metamorphism. The Hutuo Group did not undergo the D1 deformation, either because sedimentation was coeval with the D1 deformation or because it was at a high structural level and was not influenced directly by the early deformation. The D2 deformation produced NW-verging asymmetric and recumbent folds. The D2 deformation is interpreted to have resulted from collision between the Eastern and Western Blocks of the North China Craton. In the Hutuo Group and the Fuping Complex, the development of ESE-verging asymmetric tight folds is associated with D2. The structural pattern resulting from superimposition of D1 and D2 is a composite synform in the Hengshan–Wutai–Fuping Complexes. All four lithotectonic units were superposed during the later D3 deformation. The D3 deformation developed NW-trending open upright folds. Ongoing collision led to development of transpressional ductile shearing (STZ2), forming the transpressional Zhujiafang dextral ductile shear zone between the northern Hengshan Complex and the southern Hengshan Complex, and generating the sinistral Longquanguan ductile shear zone between the Fuping Complex and the Wutai Complex, respectively. The STZ1 and D2 deformation were possibly responsible for fast syn-collisional exhumation of the high pressure mafic granulites and retrograded eclogites. The structural patterns and elucidation of the deformation history of the Hengshan–Wutai–Fuping Complexes places important constraints on the tectonic model suggesting that an oceanic lithosphere between the Eastern and Western Blocks underwent northeastward-directed oblique subduction beneath the western margin of the Eastern Block, and that the final closure of this ocean led to collision between the two blocks to form the coherent basement of the North China Craton. [Copyright &y& Elsevier]

Stationary models are usually applied for wind characteristics analysis. However, nonstationarity has been found in the field measurements of typhoons in recent studies; therefore, using traditional models with stationary assumptions to conduct wind characteristics is inadequate. In this research, data acquisition of typhoon wind speeds and monsoon are conducted based on the wind field measurements. Wind speeds of typhoon "Maria" passing through Pintan, Fujian Province, China and the monsoon from 2017.10–2018.10 were obtained to investigate wind characteristics. The run test method is utilized to show that non-stationarity exists in both typhoon and monsoon wind speed, and the percent of non-stationary increases with the increase in time interval. Additionally, results show that stronger non-stationarity exists in typhoon wind speed compared with monsoons. Based on a self-adaptive procedure to extract time varying mean wind speed, a non-stationary model is established to compare with the non-stationary model, which has been applied in the traditional wind characteristic analysis. The fluctuating wind characteristics such as turbulence intensity, gust factor, turbulence integral scale, and wind speed spectrum are analyzed to compare the two models. Results show that the difference of such characteristics between the two models increases with the time interval, indicating the necessity of consideration of non-stationary models, especially for design specifications with larger time intervals. Influences of time intervals are investigated, and relevant recommendations are provided for wind resistance specifications. Our conclusions may provide reference for wind resistance design in engineering applications. [ABSTRACT FROM AUTHOR]

Abstract: The Xuefeng Tectonic Belt is an important intraplate structural system in the South China Block. Its west margin is up to 1300km away the present-day continental margin, and the Mesozoic structural trends in this belt are perpendicular to and have no correlation with the Triassic Qinling-Dabie Orogenic Belt. This belt provides important clues for understanding the mechanism of intraplate deformation and the tectonic history of South China. We identified two generations of folding with different strike directions in the Xuefeng Tectonic Belt based on the youngest folding-involved strata and their overprinting relationship. The early one is NE-striking, overprinted by the N–S-striking folds both during Late Jurassic and Late Cretaceous. Thrust faults in the Xuefeng Tectonic Belt mainly show top-to-west thrust movement, which is approximately coeval with the N–S-striking folding. The thrust fault system can be divided into three zones: the root zone with steep thrusts, the middle zone characterized by imbricate thrusts, and the frontal zone with a few shallow thrusts. In addition, two generations of strike-slip faults with different structural trends have been identified: E–W-striking strike-slip faults showing dextral transpression, and NE-striking strike-slip faults with sinistral offset and controlling the upper Cretaceous basins. According to regional geological relationship and structural overprinting, we interpret that the E–W trending strike-slip faults formed in the first stage, whereas the NE-striking strike-slip faults formed later during an E–W-oriented compressional event. Therefore, the principal stress direction varies from NW–SE to E–W. [Copyright &y& Elsevier]

Abstract: The Cenozoic Bohai Bay Basin is located at the center of the Eastern Block of the North China Craton. The structural architecture of this basin provides important clues on the deep-seated lithosphere thinning of the North China Craton. The Cenozoic regional stress field is characterized by NW-oriented extension. However, the various Cenozoic structural patterns of normal faulting and related transverse folding in the Bohai Bay Basin are controlled not only by Cenozoic stress field, but also by strain field and Mesozoic basement fault assemblages in this area. Regionally, the Cenozoic tectonic features and the dynamic evolution of the eastern North China Craton are dominated by two lithosphere-penetrating fault systems including the sinistral Tan–Lu Fault System and the dextral Lan–Liao Fault System. To the west of the Lan–Liao Fault System, Cenozoic extensional tectonics includes NNE-trending listric normal faults that controlled half grabens. However, between these two fault systems are WNW-trending half grabens which show basement-involved faulting in the north and overlapping relations between sedimentary cover and basement in the south. To the east of the Tan–Lu fault, the North Yellow Sea Basin is a WNW-trending fault depression with faulting in the south and overlapping relations in the north. These structural features are inherited from the Mesozoic tectonic framework of this area, whose tectonic characteristics were completely controlled by two opposite strike-slipping faults, the trans-extensional or oblique rifting in the Paleogene, followed by extensional faulting and subsequent subsidence. Furthermore, the culmination of the decratonization of the North China Craton was also related to an eastward jump of Cenozoic subduction of the Pacific Plate and the far-field effect of eastward extrusion of Cenozoic subduction of the Indian Plate, and was not essentially restricted to the early Mesozoic processes. Therefore, the Cenozoic, especially ∼25Ma marks the time of cessation of the processes that led to lithosphere thinning and destruction of the Eastern Block of the North China Craton. [Copyright &y& Elsevier]

Abstract: Mesozoic basins occur widely in the Eastern Block and the neighboring area of the North China Craton, including the Bohai Bay, the Jiaolai, the Hefei and the North Yellow Sea in the north, and the Jianghan and the Subei-South Yellow Sea basins to the south. Their spatial–temporal framework is the consequence of the Indosinian and Yanshanian tectonic regimes in eastern China and record the events related to Mesozoic deconstruction of the North China Craton. Our results demonstrate that the Mesozoic tectonic evolution of the eastern North China Craton was related to both sub-crustal delamination and intra-crustal extrusion or escape tectonics. Thus, we propose that the mechanism of uplift of the Yanshanian North China Plateau and related lithosphere thinning in the eastern North China Craton were related to sub-crustal delamination at depth. However, the different distribution patterns of the basins on both sides of the Tan-Lu Fault System as well as the co-existence of both compressional and extensional basins in the Mesozoic indicate that these were controlled by escape tectonics in different tectonic parts of the crust. [Copyright &y& Elsevier]

The Mesozoic Western Pacific subduction system significantly impacted the North China and South China blocks along the East Asian continental margin and influenced the tectonic, magmatic, metallogenic and geomorphic evolution of the region. However, the dynamics and impact on the zone along the East Asian ocean-continent connection zone remain debated. Here we provide a comprehensive synthesis of the state-of-the-art information from deformation analysis, magmatism, geochronology, tomography and other fields from this region. We evaluate first the pre-Yanshanian (pre-Jurassic) final assembly of blocks and the Late Triassic formation of the unified continental margin in East China. We then focus on the Jurassic and Cretaceous geological processes in the East Asian ocean-continent connection zone. The temporal and spatial evolution of structural propagation, sedimentary depocentre, age zonation and migration of magmatism, as well as the large-scale tectono-morphological inversion in the Earth surface system combined with deep processes, are probed. In the early Yanshannian Period (Early and Middle Jurassic, 200–160 Ma), the destruction of the North China Craton (NCC) was mainly affected by the westward early-stage layered rollback, and stepwise delamination and thinning of its continental lithosphere, resulting in the early Yanshanian westward migration of tectonism and magmatism. Coevally, the combined effect of the closure of the Mongal-Okhotsk Ocean to the north and the subduction of the Bangong-Co- Nujiang Ocean to the south imparted an overall compressional setting in the East Asian Ocean-Continent Connection Zone (EAOCCZ). The centres of asthenospheric upwelling and mantle extrusion at depth continued to migrate eastward, driving the eastward lithospheric thinning with periodic and alternating extension and compression. The South China Block experienced a westward flat subduction during the early Yanshanian Period, resulting in the westward propagation of deformation and magmatism, followed by late two-stage delamination to induce the eastward tectono-magmatism. The difference in tectono-magmatic styles between the North China and South China blocks is a result of the different mechanisms and syles of the deep delamination processes under the superconvergence regime of the East Asian and adjacent plates. Especially delamination under North China generated the northwestward layered and fractured subcontinental lithospheric mantle, whereas under the eastern South China Block, were the oceanic lithospheric mantle of the Paleo- Pacific Plate that underwent flat subduction, or continental garnet peridotite mantle. In the middle Yanshanian Period (Late Jurassic to early Early Cretaceous, 160–125 Ma), the EAOCCZ underwent escape tectonics to form some basins related to strike slip faulting. Generally the extensional basins in the tails of the triangular-shaped escape blocks are perpendicular to the extrusion direction. The transtensional or transpressional basins are controlled by the strike slip faults distributed on both sides of the triangular block, and the flexural basins occur in front. In the late Yanshanian Period (late Early Cretaceous-Late Cretaceous, 125–65 Ma), the Paleo-Pacific (Izanagi) Plate subducted NNW-ward beneath the Eurasian continent, and the subduction angles changed gradually following eastward mantle extrusion induced by the closure of the Okhotsk Ocean to the north and Bangong-Nujiang Ocean to the south, as well as the rollback and subduction retreat of the Paleo-Pacific Plate to the east. The EAOCCZ gradually experienced lithospheric collapse and the formation of metamorphic core complexes, as well as obvious landscape reversal. During 70–45 Ma, the Izanagi-Pacific Ridge subducted beneath the EAOCCZ to induce wide uplift resulting in the formation of the Cenozoic dextral transtension-related basins. [ABSTRACT FROM AUTHOR]

The East China Sea Shelf Basin lies between the Pacific Subduction and Indian-Eurasian Collision tectonic domains and records Cenozoic tectonic inversion, especially in the Xihu Sag. To improve the understanding of the evolution and mechanism of tectonic inversion, this paper employs analogue modelling to reproduce the evolutionary process. Combined with the structural analysis of seismic profile, this paper determines the pattern of basement-involved faults. Simulation results show that under the transtension, two subsidence centers developed and a number of normal faults assembled in two flower structures. When the stress field turned into transpression, the geometry and deformation of inversion basin inherited the previous transtensional basin and pre-existing faults, respectively. The geometry and fault patterns in models are well consistent with those observed in the Xihu Sag, which indicates the plausibility of similar deformation controls. The formation of the tectonic inversion is related to the variation in stress field caused by the changes in the rates and directions of the subduction of the Pacific Plate and the collision of the Indian Plate with Eurasian Plate. [ABSTRACT FROM AUTHOR]

Lithospheric subduction prior to the assembly of the South China and North China blocks is traditionally considered to be directed northward. However, some critical geological and geochemical data cannot be reconciled with this northward subduction. This paper presents new lines of evidence against the traditional models and proposes a new and revolutionary tectonic model to explain the distribution and exhumation of high pressure (HP)-ultrahigh pressure (UHP) metamorphic rocks of the Dabie-Sulu Belt. We emphasize the following: 1) The Triassic tectonic environment of the southern margin of the North China Block was passive, not active, based on the stratigraphy; 2) In the southern margin of the North China Block no arc magmatism was recorded. 3) Many Paleoproterozoic slices of Jiaobei affinity of the Jiao-Liao-Ji Belt in the North China Block were located in the Triassic Sulu Orogen. 4) Many 1.85 Ga metamorphic zircons are preserved in the Dabie-Sulu high pressure-ultra-high pressure (HP-UHP) metamorphic rocks. 5) The geometric asymmetry of many structural patterns in the HP-UHP slices indicates top-to-the northwest thrusting during the exhumation of HP-UHP slices. 6) Blueschists occur in the south of the UHP eclogite slices. 7) In the eastern segment of the North Qinling Orogen, no components with an affinity of the South China Block have been found. Along the Shangdan Suture of the Qinling Orogen has been recorded an apparent northward subduction. We consider that the suture is just a lateral subduction zone rather than a major collisional zone. Along the Shangdan Suture, the rarity of I-type plutonism can be attributed to a transform-type continental margin. The Bureya-Jiamusi-Khanka Block has an affinity to the South China Block based on its similarity regarding the Paleozoic history of deformation and Triassic blueschist metamorphic facies metamorphism. The Bureya-Jiamusi-Khanka Block could be the northern extension of the Dabie-Sulu Belt, and this gigantic belt could be interpreted as an orocline related to the southeastward subduction of the North China Block beneath the Greater South China Block. [ABSTRACT FROM AUTHOR]

During the Mesozoic–Cenozoic, the central North China Block underwent complex tectonic transition and significant changes of tectonic geomorphology. This apatite fission track study shows that the west part of the Taihang Mountains experienced a rapid event which commenced before 160 Ma and lasted until 135 Ma, together with the extensive development of folds and thrusts, indicating this area experienced intense compression and uplift. Combined with the petrological and geological characteristics, the exhumation event represents the uplift of the Yanshanian North China Plateau and the Taihang Mountains inside it. During the Cenozoic, two episodes of rapid cooling events took place during 65–55 Ma and after 25 Ma, respectively. The former one corresponds with the formation of the Bohai Bay Basin (BBB), which led to the extensional denudation of the Taihang Mountains. The formation of the Bohai Bay Basin disrupted the Yanshanian North China Plateau, caused the negative inversion of the tectonic geomorphology in the central North China Block. The thermal models indicates that the formation of north and south parts of the BBB commenced simultaneously in the south and north parts of the Taihang Mountains, implying the dynamics should be derived from the west or the east, rather than the north or the south. The latter cooling event took place earlier in the north part of the Taihang Mountains than the south part, corresponding with the Miocene thermal subsidence of the BBB. [ABSTRACT FROM AUTHOR]

The Zhangjiakou-Penglai Fault Zone (ZPFZ), as a large-scale WNW-trending active fault zone with frequent seismic activity, is an area prone to moderate to intense earthquakes across North China. A detailed analysis of the ZPFZ has been carried out based on earthquake activity, deep structural response, dynamic mechanism and physical simulation by conducting an en échelon fault model experiment. The results show that the ZPFZ is a lithospheric active fault zone that has controlled some small en échelon Quaternary pull-apart basins and has triggered many earthquakes as seismogenic structures. The earthquake location and intensity distribution by the experimental simulation fit well with those of actual earthquakes. The earthquake distribution is controlled obviously by the en échelon structural properties. The intensity of seismic activity is strong in the middle and weak at the western and eastern ends of the fault zone, migrating from the southeast to the northwest along the entire fault zone. This WNW-trending fault zone in North China, is closely related to the surrounding plate activities. The ZPFZ is not only dominated by the collision of the Indian Plate to the Eurasian Plate, but is also influenced by the subduction of the Pacific Plate. It depends on the comprehensive reflection of two geodynamic settings from the western collision of the Indian to the Eurasian plates and the eastern subduction of the Pacific Ocean Plate to the Eurasian Plate. [ABSTRACT FROM AUTHOR]

The Qinling–Qilian orogen preserves the records of Early Paleozoic convergence among the Proto-Tethyan micro-blocks. In this study, we analyze the seismic velocity structure and the aeromagnetic anomalies in the Qinling–Qilian orogen and its adjacent areas, showing that the northernmost boundaries of these Proto-Tethyan micro-blocks are defined by the Guyuan–Longshoushan Fault in the Qilian orogen and by the Luonan–Luanchuan Fault in the Qinling orogen, respectively. The lithosphere north of the Qinling–Qilian orogen subducted southward under the Qinling–Qilian orogen. The boundaries of the micro-blocks in the Qinling–Qilian orogen of the Proto-Tethys domain are mostly EW- or NE-trending. Combined with Early Paleozoic geological records, our results indicate that the south-dipping low-velocity anomaly under the Alxa block and the south-dipping high-velocity ones under the North Qilian orogen and the North China block might indicate that the Alxa block, the North Qilian Oceanic slab and the North China block subducted southward. The south-dipping high-velocity anomaly under the North Qilian orogen is interpreted as the remnant of the Proto-Tethys Ocean in that area. However, the north-dipping low-velocity anomaly under the South Qinling and the North Qinling orogens, the Qaidam block and the north-dipping high-velocity one under the Yangtze and the Bikou blocks suggest that the South Qinling and the North Qinling orogens, the Qaidam, the Yangtze and the Bikou blocks subducted northward. The present spatial framework of the Qinling–Qilian orogen is related to Early Paleozoic convergence among the Proto-Tethyan micro-blocks. [ABSTRACT FROM AUTHOR]

• A laboratory experimental device for flow-induced vibration of leaching tubing was developed based on similarity principle. • The influences of main operation parameters on the vibration characteristics of leaching tubing were analyzed systematically. • The research results provide theoretically guidance for practical application of leaching tubing in salt cavern gas storage. To address flow-induced vibration failure problems of water solution leaching tubing string in salt cavern gas storage, a laboratory experimental device for flow-induced vibration of leaching tubing string was developed based on the similarity principle, and the corresponding experimental bench was built, according to the on-site parameters of the M gas storage well in Jianghan Oilfield, China. The vibration simulation experiments were carried out, and the displacement and amplitude-frequency response data at the bottom end of the tubing string were measured. The influences of different operation parameters and structure modes, such as water injection flow rate, two-port distance, screen structure and circulation mode, on the vibration characteristics of the tubing string were explored, the failure mechanism of the leaching tubing string was revealed, and the corresponding vibration failure control methods were proposed. The results obtained demonstrate that, first, at the moment of pump start-up (corresponding to well opening on-site), the tubing string produced obvious water hammer phenomenon. With the increase of the water injection flow rate, the vibration displacement and frequency of the center tube first increase and then decrease, when the water injection flow rate is less than 1.55 L/min (corresponding to the on-site flow rate of 40 m3/h), the risk of vibration failure of leaching tubing can be reduced. Second, when the two-port distance is greater than 0.16 m (corresponding to the on-site two-port distance of 45 m), the amplitude and frequency of lateral vibration of the center tube increase significantly, and the risk of lateral vibration deformation of leaching tubing increases. Third, adding a symmetrical hole screen at the bottom of the center tube can significantly reduce the vibration displacement and frequency of leaching tubing, and improve the safety of the operation tubing string. Fourth, the vibration displacement and amplitude of the leaching tubing in the reverse circulation mode are smaller than those in the positive circulation mode. When the cavern shape requirements are met on-site, the vibration of the tubing string can be effectively reduced by using the reverse circulation cavern leaching. [ABSTRACT FROM AUTHOR]

Abstract: The Paleoproterozoic Jiao-Liao-Ji Belt separates the Eastern Block of the North China Craton into two small sub-blocks: the northern Longgang and the southern Rangrim blocks. However, it still remains unknown or controversial about the subduction polarity, collisional deformation and kinematics between two sub-blocks. The southern segment of the belt consists of the Paleoproterozoic Fenzishan and Jingshan groups, and Paleoproterozoic high pressure mafic granulites and serpentinites blocks which are located in the Jiaodong Complex. All of which are separated from the Jiaodong Complex of Neoarchean TTG gneisses by STZ1 ductile shear zones. Structural analysis in this study indicates that most of the rocks in all the units of the southern segment of the Jiao-Liao-Ji Belt underwent three distinct episodes of folding (D1 to D3) and two stage of ductile thrust shearing (STZ1 coeval to D1 and D2, STZ2 between D2 and D3). The D1 deformation formed penetrative axial planar foliations (S1), bedding-parallel ductile shear zone, mineral stretching lineations (L1), and rarely preserved small isoclinal D1 folds in the Jingshan and Fenzishan groups. In the Jingshan Group, however, penetrative deformational transposition resulted in stacking of sedimentary compositional layers which are separated by bedding-parallel ductile shear zones (STZ1) at a period of about 1956Ma to 1914Ma. The kinematic indicators of STZ1 in the Jingshan Group with resultant prograde peak metamorphism up to granulite facies grade and the Fenzishan Group with peak metamorphism up to amphibolite facies grade indicate NW-directed compression. D2 resulted in crustal thickening with retrograded medium pressure granulite facies grade at about 1914–1893Ma. The D2 deformation produced NW-verging asymmetric and recumbent folds, interpreted to have resulted from basement-involved thicken-skin structures. The Jiaodong Complex was also involved into the development of WNW-verging asymmetric tight folds associated with D2 in the Jingshan and the Fenzishan groups. Ongoing collision led to the development of transpressional ductile shearing (STZ2), forming the transpressional Taipingzhuang dextral ductile shear zone between the Jingshan Group and the southern Archean Complex and the transpressional Tading-Xiadian sinistral ductile shear zone between the Jingshan Group and the northern Archean Complex. All three lithotectonic units were superposed during the late D3 deformation with amphibolite facies metamorphism. The D3 deformation developed WNW-trending open to tight upright folds at about 1893–1875Ma. The structural pattern resulting from superimposition of D2 and D3 is a composite synform in the Fenzishan and Jingshan groups. The structural events of D1 and STZ1, and D2 and STZ2 deformation were possibly responsible for fast syn-collisional exhumation of the high pressure mafic granulites. The structural patterns and deformational history of the Fenzishan and Jingshan groups suggest a southeastward-directed oblique subduction beneath the northwestern margin of the Rangrim Block, and that the final scissor-shaped closure of the rift led to collision between the two blocks to form the coherent basement of the Eastern Block of the North China Craton. [Copyright &y& Elsevier]

Abstract: Along the Qinling–Dabie–Sulu orogenic belt in China crops out the world''s largest terrane composed of ultrahigh-pressure (UHP) metamorphic rocks. Differences in the timing and mechanisms of oceanic and continental subductions are assumed to be responsible for different ages of high-pressure (HP) and UHP slices in different parts of the belt. The western part of the Dabie orogen (western Dabie terrane) holds a key to understanding of the transition from oceanic to continental subduction. This paper reports geochronological results to test a two-stage tectonic model for the exhumation of HP/UHP rocks in western Dabie. This model involves two different stages and types of extrusion for exhumation of the HP/UHP rocks in east-central China. Mica Ar/Ar ages, ranging from 241 to 231Ma, indicate a general middle Triassic cooling probably driven by early upward extrusion during the collision between the North and South China Blocks. Late Triassic–Early Jurassic cooling was associated with later eastward extrusion, ranging from 200 to 184Ma. The second event is recorded also in mica in the region that was not affected by later deformation and magmatism. The lateral movement along lithosphere-scale faults resulted in the eastward extrusion of the HP–UHP metamorphic terrane, which was followed, in the Late Triassic–Early Jurassic time, by a major compressive event. These two extrusion events are correlative with the two stages of Triassic exhumation of the western Dabie HP–UHP rocks, respectively. Wintin the framework of the Qinling–Dabie–Sulu orogenic belt, it is suggested for western Dabie that the subduction/exhumation of blueschist-facies unit is related to the Mianlue suture, whereas the subduction/exhumation of HP/UHP eclogite-facies units is related to the Shangdan suture. [Copyright &y& Elsevier]

• The Moho depth in Ordos Block ranges 38 ~ 42 km in the east and deepens to over 44 km in the west. • Paleo-rift structures are revealed by Moho discontinuity and deep gravity gradient fields. • The paleo-rifts should be related to the Meso-Neoproterozoic aulacogens. • Residual Meso-Neoproterozoic strata controlled by the paleo-rifts are distributed from southwest to central Ordos Block. • Five favorable areas are constrained and three types of play are speculated upon the potential Meso-Neoproterozoic petroleum systems. In order to evaluate the potential petroleum system within the Meso-Neoproterozoic strata of the southwest North China Craton (NCC), we explored the deep-buried basal tectonics on the Precambrian basement and the residual sedimentary thickness of the Meso-Neoproterozoic in the Ordos Basin. A combination of geophysical processing methodologies has been conducted. Based on regional seismic exploration, the shallow gravity effects caused by the undulation of the Cenozoic, Jurassic, Carboniferous and Cambrian sedimentary formations were calculated through forward modeling, and eliminated the free-air gravity anomaly by a gravity stripping technique. Subsequently, by using the wavelet multi-scale decomposition method, the deeper gravity effect sourcing from underneath the Meso-Neoproterozoic base was calculated and then eliminated, including the undulation of Paleoproterozoic-Archaean crystalline basement and the lateral density discontinuity of the lower crust. As a result, the residual gravity anomalies caused by the Meso-Neoproterozoic sedimentary formations and the Moho discontinuity of the Ordos Block were both obtained, which was then used for inversion. The inversion results show that the residual Meso-Neoproterozoic strata are mainly distributed in the southwest and northern part of the Ordos Block, and the Moho depth of the Ordos Block averages about 42 km. It ranges from 38 to 42 km in the eastern part and deepens to over 44 km in the west. In addition, there are some detailed deep-structure reflections on the Moho discontinuity. For instance, the parallel-arranged NE-trending anomalous belts in southwest Ordos Block indicate strong crustal extension and mantle uplift. The regional geology indicates that the NE-trending crustal extension is not related to the Cenozoic strike-slip pull-apart process around the Ordos Block, nor the Indosinian Movement in Early Mesozoic, or the cratonic depression in the Paleozoic. However, it highly resembles the NE-oriented paleo-rifts that developed in the Meso-Neoproterozic aulacogens. The residual crustal gravity anomaly eliminates both the shallow disturbance from the sediments and the deep shadow from the mantle. It shows very good consistency with the undulation of the Meso-Neoproterozoic sedimentary basement along a classical interpreted seismic survey line, which validates the correlation between the NE-trending anomalous belts with the basal aulacogen tectonics. According to seismic interpretation, the paleo-rifts within the Precambrian aulacogens occurred during the Mesoproterozoic and continued into the early Neoproterozoic. Huge volumes of sediment filled the rift troughs during the Meso-Neoproterozoic, causing a significant gravity loss on the gravity field, and formed considerable oil–gas exploration potential. Given suitable paleoclimatic conditions, the grabens would have provided a favorable environment for organic-rich shales and source rocks to develop. While the faults controlling the grabens and horsts would have played an important role in the migration and accumulation of hydrocarbons in the potential petroleum system. Combined with paleoclimate and lithofacies paleogeography analysis, five favorable areas are speculated for Meso-Neoproterozoic potential petroleum systems, which are the northwest Yimeng Uplift, the northern Tianhuan Depression, the southern Tianhuan Depression, the southwestern to central Yishaan Slope and the western Weibei Uplift, respectively. Based on lithofacies paleogeography, source rock maturity and organic carbon abundance, it suggests that the favorable petroleum systems within the Proterozoic strata of the Ordos Block were obviously controlled or influenced by the deep paleo-rifts and block faults, which resulted in forming three types of play, called the Weathering Model, the Tilting Model and the Transition Model. In particular, the central to western parts of the Yimeng Uplift and the southern Tianhuan Depression, where the Weathering Model developed, as the Upper Paleozoic coal-bearing source rocks have large hydrocarbon generation potential and good preservation conditions, these two areas should be regarded as important favorable prospecting regions in the Ordos Basin. [ABSTRACT FROM AUTHOR]

The Meso-Neoproterozoic period, sometimes referred to as the 'boring billion' or 'Earth's middle age', spans the interval between the formation of the Columbia and Rodina supercontinents. It is regarded as a stable era of the Earth. However, from a global perspective, there are many intensive events of mafic volcanism, dyke intrusions and formation of rift basins recorded in different cratons during this period. This paper focuses on rift basins that developed in three cratons in China (North China, South China and Tarim cratons), because large-scale primary gasfields, as one of the deep resources, have been discovered recently in rocks of Meso-Neoproterozoic age. The formation mechanisms and tectonic settings of these rift basins as the targets of Deep Earth are discussed, based on the restoration of global positions of the three cratons by pre-existing paleomagnetic data and plate reconstruction. We recognise that the rift basins of the North China Craton are related to extrusion tectonics in the southwest Ordos Block or are pull-apart basins along the northern and southern sides of the Ordos Block. The rift basins of the South China Craton are derived from mantle lithospheric delamination of the Jiangnan Orogen in the eastern South China Craton or subduction retreat and backarc opening in the western South China Craton, respectively. The rift basins of the Tarim Craton originated from the backarc opening along the margin of the Supercontinent Rodinia. [ABSTRACT FROM AUTHOR]

• The North China Craton experienced long-term extension during the Mesoproterozoic and discrepancy of the basin evolution in different areas of the NCC. • The earliest deposition after the cratonization of the NCC may be from the southern NCC. • Three set of the fine-grained formations in the central NCC hold the potential for hydrocarbon. Along with the breakup of the supercontinent Nuna and Rodinia during the Mesoproterozoic and Neoproterozoic, a series of sedimentary basins formed within or at the periphery of the ancient cratons. Under the regime of breakup of the supercontinent, these basins underwent different evolutionary history hence formed different geological elements constituting the petroleum systems. In this contribution, the distribution and the stratigraphic successions of the Meso-Neoproterozoic basins in the North China Craton (NCC) were examined, as well as the retrospective review for the mechanisms of the basin formation. The synthesized geological and geochronological data support a long-term extensional environment for the basins in the northern NCC. The Mesoproterozoic basins in the Yanshan, western Liaoning (Yan-Liao) and the Zhaertai areas formed at the intracratonic position later than that in the Bayan Obo, which possibly deposited in the continental margin. The further efforts still need to be devoted to decipher the huge controversial around the tectonic nature of the basins in the southern NCC, as well as their stratigraphic correlations with the basins in the north and central. The distribution and organic geochemical characteristics of the Mesoproterozoic source rock were also summarized. Three sets of source rock in the central NCC, namely the Chuanlinggou, Hongshuizhuang and Xiamaling Formations developed favorable geological and geochemical conditions for the generation of the hydrocarbon. While in the south, the Cuizhuang Formation was the only interval feasible for potential source rock. The progress in seismic geophysics and borehole drilling suggested the existence of the Mesoproterozoic beneath deep Ordos Basin. This open a new window for the reconstruction of the Mesoproterozoic paleogeography as well as the evaluation of the source potential of the Mesoproterozoic basins in the North China Craton. [ABSTRACT FROM AUTHOR]