115 research outputs found
Geological and isotopic geochemical constraints on the evolution of the Fuping Complex, North China Craton
No full textThe Neoarchean to Paleoproterozoic Fuping Complex together with the adjacent Hengshan and Wutaishan complexes form the middle part of the Central Zone that separates the North China Craton into the Eastern and Western Archean continental blocks. The Fuping Complex comprises three major lithological assemblages: the similar to 2.50 Ga Fuping trondhjemite-tonalite-granodiorite (TTG) gneisses, the Wanzi paragneisses, and the 2.08 and 2.02 Ga Nanying granitic gneisses. The TTG gneisses contain abundant enclaves of highly-metamorphosed supracrustal rocks, including similar to 2.70 Ga mafic granulites and amphibolites with e(Nd)' of + 3.29 to + 3.96 and T-DM of 2.72-2.82 Ga, and are characterized by T-DM of 2.76-3.04 Ga and a linear correlation between 6(Nd)' (- 1.64 to + 0.96) and 1/Nd, indicative of mixing of melts derived from the similar to 2.70 Ga metabasic rocks and similar to 3.0 Ga crustal materials. Mafic dikes along the Chengnanzhuang shear zone were most likely emplaced at similar to 2.31 Ga and have e(Nd)(t) of + 2.24 to + 4.78 and T-DM of 2.34-2.59 Ga. The Nanying granitic gneisses with E-Nd(t) of - 4.04 to - 5.24 were most likely related to partial melting of the similar to 2.70 Ga supracrustal rocks and/or the - 2.50 Ga TTG gneisses. These geological relationships and isotopic data suggest that the Fuping Complex probably formed from the following live major tectonomagmatic events: (1) mafic, magmatism and early crustal growth at similar to 2.7 Ga, with the possible existence of older ( - 3.0 Ga) crust(s); (2) collision-related crustal thickening, underplating of basaltic magma, high-grade metamorphism, crustal anatexis and TTG magmatism at similar to 2.5 Ga; (3) extensional deformation and emplacement of the mafic dikes and the Nanying granitic plutons along the Chengnanzhuang shear zone ( similar to 2.5 to similar to 2.0 Ga); (4) S-type granitic magmatism and associated amphibolite-facies metamorphism ( similar to 2.0 to similar to 1.80 Ga); and (5) emplacement of granitic pegmatite dikes at similar to 1.80 Ga. (C) 2002 Elsevier Science B.V. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000177793500003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Geosciences, MultidisciplinarySCI(E)166ARTICLE1-241-5611
Crustal growth and intracrustal recycling in the middle segment of the Trans-North China Orogen, North China Craton: a case study of the Fuping Complex
No full textThe most important crustal growth on Earth occurred at similar to 2.7 Ga, but the North China Craton (NCC) is characterized by prevalent development of similar to 2.5 Ga juvenile crust, with relatively rare records of similar to 2.7 Ga crustal growth. The Fuping Complex in the middle segment of the Trans-North China Orogen (TNCO) between the Eastern and Western blocks of the NCC is composed mainly of similar to 2.5 Ga Fuping tonalitic-trondhjemitic-granodioritic (TTG) gneisses and Longquanguan augen gneisses, similar to 2.1 Ga Nanying granitic gneisses and the Wanzi supracrustal rocks. Previous studies have suggested one major phase of crustal growth at similar to 2.5 Ga, possible intracrustal recycling at similar to 2.1 Ga and the presence of older rocks in the Fuping Complex, but there has been no record of similar to 2.7 Ga crustal growth. The Fuping TTG gneisses are dominated by stromatic migmatite, and new U-Pb dating of magmatic zircons from two stromatic migmatite samples yielded three different ages: (1) 2.75 Ga, which is the oldest age obtained from the Fuping TTG gneisses, (2) 2.54 Ga, which just falls in the published zircon U-Pb age range of 2.53 to 2.47 Ga for the Fuping TTG gneisses, and (3) 2.11 Ga, which is almost the same as the age of the Nanying granitic gneisses. Therefore, there are two generations of TTG gneisses in the Fuping Complex. Importantly, both of the 2.75 and 2.54 Ga zircons have the highest epsilon(Hf)(t) values, almost equal to the contemporaneous depleted mantle. This indicates high contributions of juvenile material to the two generations of TTG gneisses. In contrast, the 2.11 Ga zircons have apparently low epsilon(Hf)(t) values of -0.47 to +2.04, just falling in between 2.55 and 2.75 Ga continental crust values. This strongly suggests the reworking of the two generations of TTG gneisses at 2.1 Ga. Zircon U-Pb and Hf isotopes convincingly reveal two major phases of crustal growth in the Fuping Complex at similar to 2.7 and similar to 2.5 Ga, the same as in the northern and southern segments of the TNCO, and also confirm one major phase of intracrustal recycling at similar to 2.1 Ga, which may be responsible for the Nanying granitic gneisses.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000304828900011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Geosciences, MultidisciplinarySCI(E)17ARTICLE4729-74214
Polyphase deformation of the Fuping Complex, Trans-North China Orogen: Structures, SHRIMP U-Pb zircon ages and tectonic implications
No full textThe Fuping Complex is located in the central part of the Trans-North China Orogen (TNCO), a Paleoproterozoic collisional belt along which the Eastern and Western Blocks were assembled to form the North China Craton. Three stages of deformation (D1-D3) have been identified in the Fuping Complex. D1 formed tight to isoclinal folds F1, penetrative foliation S1 and mineral lineation L1, which resulted from the early NW-SE-orientated thrusting and shearing. D2 progressively overprinted D1 and was dominated by mostly NW-SE shortening and top-to-the-SE(E) thrusting under a compressive environment. D1 and D2 occurred in association with the peak metamorphism (M1). D3 occurred during the exhumation after the crustal thickening, producing regional-scale NWW-SEE-trending open folds (F3) and associated low-angle detachment faults, and was responsible for the isothermal decompression (M2) metamorphism of the complex. Following the D3 deformation, the complex was exhumed to shallow crustal levels where the rocks underwent the retrogressive cooling (M3) metamorphism. Syn-tectonic leucocratic dykes are widespread in the Fuping Complex. Two leucocratic dykes that did not experience D1 but underwent D2 yield SHRIMP zircon ages of 1843 ± 12 Ma and 1844 ± 18 Ma, which indicate that D1 must have occurred at some time earlier than ∼1844 Ma, whereas D2 must have occurred at some time later than this age. Two weakly deformed post-D2 leucocratic dykes yield SHRIMP zircon ages of 1817 ± 14 Ma and 1815 ± 45 Ma, suggesting that the D2 deformation occurred in the period 1843-1815 Ma. The new SHRIMP data indicate that the collision-related deformation of the Fuping Complex must have occurred in the Paleoproterozoic, not in the late Archean. Structural and geochronological data presented in this study, in association with previous lithological and geochemical data, suggest that the Fuping Complex may have been located in the hinterland of an eastward subduction zone and underwent intensive deformation and metamorphism involved in the final collision between the Western and Eastern Blocks at ∼1.85 Ga. © 2008 Elsevier Ltd. All rights reserved.link_to_subscribed_fulltex
Geochemistry of the Paleoproterozonic Nanying granitic gneisses in the Fuping Complex: implications for the tectonic evolution of the Central Zone, North China Craton
No full textThe Nanying granitic gneisses represent a major similar to 2.0 Ga magmatic event in the Fuping Complex of the Central Zone of the North China Craton. They occur in the Chengnanzhuang shear zone, which is chiefly developed along the contact between the Neoarchean Fuping tonalite-trondhjemite-granodiorite (TTG) gneisses and the Wanzi paragneisses. The Nanying granitic gneisses were derived from monzogranite and syenogranite, with minor amounts of quartz diorite and granodiorite, and belong to the metaluminous to peraluminous, high-potassium calc-alkaline series, correlations between major and trace elements, and similarities in chondrite-normalized rare-earth-element (REE) patterns, support field relationships (e.g. gradational contacts) indicating that the Nanying granitic gneisses originated from similar magmas. The granodioritic, monzogranitic and syenogranitic gneisses have similar ranges of initial Sr-87/Sr-86 values (0.7030-0.7093, 0.7021-0.7193 and 0.7049-0.7111, respectively), although these variations are partly attributable to local resetting of the isotopic system during late deformation/hydrothermal alteration. The whole-rock Pb-208/Pb-204, Pb-206/Pb-204 and Pb-207/Pb-204 values of the Nanying granitic gneisses are 37.32-76.8, 15.24-23.82 and 14.92-17.92, respectively. These Sr-Pb isotope systematics, together with previously published Nd isotope compositions, suggest that the Nanying granitic gneisses were derived from partal melting of the similar to 2.50 Ga Fuping TTG gneisses, with local assimilation involving the Wanzi paragneisses. The Nanying granitic gneisses are geochemically similar to the C-CA and C-CL groups of granitoids, except for a few samples, which plot in the H-LO group. The Nanying granitic gneisses exhibit depletion in Rb, Sr, Ba, Ti and U, and enrichment in Th, Nb, Zr, Hf and REE, similar to those of syn-shear, high-potassium calc-alkaline granitoids and late-shear alkaline granitoids; they therefore represent the product of a syn-collisional to post-collisional magmatic event. This collisional event, which is significantly older than the similar to 1.84-1.80 Ga event that has been proposed for the juxtaposition of the Eastern and Western Archean continental blocks in the final stabilization of the North China Craton, supports a tectonic model involving multiple collisional events for the amalgamation of the internal lithotectonic domains within the Central Zone and the assembly of the North China Craton as a whole. (c) 2004 Elsevier Ltd. All rights reserved.Geosciences, MultidisciplinarySCI(E)0ARTICLE5643-6582
Social-enterprise-oriented Innovative Mode of Rural Micro-finance
No full textThe rural micro-financial innovation is necessary because the traditional regular financial institutions can not satisfy peasant households’ demand of small-sum (or petty) loan and the support of present small-sum loan companies is limited for rural financial development. Taking Fuping Petty Loan Company as an example, we analyzed characteristics, reasonableness and continuity of social enterprise type peasant household petty loan mode. It is believed that this mode has enormous vitality in rural areas and has great promotion value. Petty loan companies have both internal and external shortages in their current development. We put forward countermeasures and suggestions for rural micro-financial innovation from legal status confirmation, fund supply and loan product innovation
Atomistic tensile deformation mechanisms of Fe with gradient nano-grained structure
No full textLarge-scale molecular dynamics (MD) simulations have been performed to investigate the tensile properties and the related atomistic deformation mechanisms of the gradient nano-grained (GNG) structure of bcc Fe (gradient grains with d from 25 nm to 105 nm), and comparisons were made with the uniform nano-grained (NG) structure of bcc Fe (grains with d = 25 nm). The grain size gradient in the nano-scale converts the applied uniaxial stress to multi-axial stresses and promotes the dislocation behaviors in the GNG structure, which results in extra hardening and flow strength. Thus, the GNG structure shows slightly higher flow stress at the early plastic deformation stage when compared to the uniform NG structure (even with smaller grain size). In the GNG structure, the dominant deformation mechanisms are closely related to the grain sizes. For grains with d = 25 nm, the deformation mechanisms are dominated by GB migration, grain rotation and grain coalescence although a few dislocations are observed. For grains with d = 54 nm, dislocation nucleation, propagation and formation of dislocation wall near GBs are observed. Moreover, formation of dislocation wall and dislocation pile-up near GBs are observed for grains with d = 105 nm, which is the first observation by MD simulations to our best knowledge. The strain compatibility among different layers with various grain sizes in the GNG structure should promote the dislocation behaviors and the flow stress of the whole structure, and the present results should provide insights to design the microstructures for developing strong-and-ductile metals. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.Large-scale molecular dynamics (MD) simulations have been performed to investigate the tensile properties and the related atomistic deformation mechanisms of the gradient nano-grained (GNG) structure of bcc Fe (gradient grains with d from 25 nm to 105 nm), and comparisons were made with the uniform nano-grained (NG) structure of bcc Fe (grains with d = 25 nm). The grain size gradient in the nano-scale converts the applied uniaxial stress to multi-axial stresses and promotes the dislocation behaviors in the GNG structure, which results in extra hardening and flow strength. Thus, the GNG structure shows slightly higher flow stress at the early plastic deformation stage when compared to the uniform NG structure (even with smaller grain size). In the GNG structure, the dominant deformation mechanisms are closely related to the grain sizes. For grains with d = 25 nm, the deformation mechanisms are dominated by GB migration, grain rotation and grain coalescence although a few dislocations are observed. For grains with d = 54 nm, dislocation nucleation, propagation and formation of dislocation wall near GBs are observed. Moreover, formation of dislocation wall and dislocation pile-up near GBs are observed for grains with d = 105 nm, which is the first observation by MD simulations to our best knowledge. The strain compatibility among different layers with various grain sizes in the GNG structure should promote the dislocation behaviors and the flow stress of the whole structure, and the present results should provide insights to design the microstructures for developing strong-and-ductile metals. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License
Inhibiting ACSL1-Related Ferroptosis Restrains Murine Coronavirus Infection
No full textMurine hepatitis virus strain A59 (MHV-A59) was shown to induce pyroptosis, apoptosis, and necroptosis of infected cells, especially in the murine macrophages. However, whether ferroptosis, a recently identified form of lytic cell death, was involved in the pathogenicity of MHV-A59 is unknown. We utilized murine macrophages and a C57BL/6 mice intranasal infection model to address this. In primary macrophages, the ferroptosis inhibitor inhibited viral propagation, inflammatory cytokines released, and cell syncytia formed after MHV-A59 infection. In the mouse model, we found that in vivo administration of liproxstatin-1 ameliorated lung inflammation and tissue injuries caused by MHV-A59 infection. To find how MHV-A59 infection influenced the expression of ferroptosis-related genes, we performed RNA-seq in primary macrophages and found that MHV-A59 infection upregulates the expression of the acyl-CoA synthetase long-chain family member 1 (ACSL1), a novel ferroptosis inducer. Using ferroptosis inhibitors and a TLR4 inhibitor, we showed that MHV-A59 resulted in the NF-kB-dependent, TLR4-independent ACSL1 upregulation. Accordingly, ACSL1 inhibitor Triacsin C suppressed MHV-A59-infection-induced syncytia formation and viral propagation in primary macrophages. Collectively, our study indicates that ferroptosis inhibition protects hosts from MHV-A59 infection. Targeting ferroptosis may serve as a potential treatment approach for dealing with hyper-inflammation induced by coronavirus infection
PCBP2 mediates degradation of the adaptor MAVS via the HECT ubiquitin ligase AIP4
No full textMAVS is critical in innate antiviral immunity as the sole adaptor for RIG-I-like helicases. MAVS regulation is essential for the prevention of excessive harmful immune responses. Here we identify PCBP2 as a negative regulator in MAVS-mediated signaling. Overexpression of PCBP2 abrogated cellular responses to viral infection, whereas knockdown of PCBP2 exerted the opposite effect. PCBP2 was induced after viral infection, and its interaction with MAVS led to proteasomal degradation of MAVS. PCBP2 recruited the HECT domain-containing E3 ligase AIP4 to polyubiquitinate and degrade MAVS. MAVS was degraded after viral infection in wild-type mouse embryonic fibroblasts but remained stable in AIP4-deficient (Itch(-/-)) mouse embryonic fibroblasts, coupled with greatly exaggerated and prolonged antiviral responses. The PCBP2-AIP4 axis defines a new signaling cascade for MAVS degradation and 'fine tuning' of antiviral innate immunity.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000271872800014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701ImmunologySCI(E)PubMed99ARTICLE121300-U101
E. fischeriana Root Compound Dpo Activates Antiviral Innate Immunity
No full textE. fischeriana has long been used as a traditional Chinese medicine. Recent studies reported that some compounds of E. fischeriana exhibited antimicrobial and immune enhance activity. Innate immune system is essential for the immune surveillance of inner and outer threats, initial host defense responses and immune modulation. The role of natural drug compounds, including E. fischeriana, in innate immune regulation is largely unknown. Here we demonstrated that E. fischeriana compound Dpo is involved in antiviral signaling. The genome wide RNA-seq analysis revealed that the induction of ISGs by viral infection could be synergized by Dpo. Consistently, Dpo enhanced the antiviral immune responses and protected the mice from death during viral infection. Dpo however was not able to rescue STING deficient mice lethality caused by HSV-1 infection. The enhancement of ISG15 by Dpo was also impaired in STING, IRF3, IRF7, or ELF4 deficient cells, demonstrating that Dpo activates innate immune responses in a STING/IRFs/ELF4 dependent way. The STING/IRFs/ELF4 axis is therefore important for Dpo induced ISGs expression, and can be used by host to counteract infection
A Study on Fracture Propagation of Hydraulic Fracturing in Oil Shale Reservoir Under the Synergistic Effect of Bedding Weak Plane–Discrete Fracture
No full textHydraulic fracturing is a critical process in the development of oil shale reservoirs. The presence of widespread bedding planes and natural fractures significantly influences the propagation of hydraulic fractures. Additionally, the injection point density plays a crucial role in the effectiveness of reservoir reconstruction. The Global Embedded Cohesive Zone Method (FEM-CZM) was employed to model the initiation and propagation of fractures from perforation holes, considering the combined effects of bedding planes and natural fractures. The results indicate the following: (1) the initiation and propagation of fractures from perforation holes lead to the co-propagation of two to four asymmetric main fractures, alongside open bedding planes and natural fractures; (2) larger bedding plane thickness and smaller bedding plane spacing promote hydraulic fractures’ tendency to propagate along the bedding planes, resulting in longer fracture lengths and predominance of tensile failure; and (3) a higher in situ stress difference facilitates the fracture’s penetration of the bedding plane, leading to an initial increase and subsequent decrease in fracture length. Tensile failure remains dominant, while the proportion of shear failure increases. Based on these findings, it is recommended to select fracturing sites with thicker bedding planes, larger bedding plane spacing, and a smaller vertical in situ stress field. Additionally, a perforation scheme with six injection points should be adopted to enhance the formation of high-efficiency seepage and heat transfer channels between hydraulic fractures, bedding planes, and natural fractures
- …
