Destruction of the North China Craton Zhu, RiXiang; Xu, YiGang; Zhu, Guang ...
Science China. Earth sciences,
10/2012, Letnik:
55, Številka:
10
Journal Article
Recenzirano
A National Science Foundation of China （NSFC） major research project, Destruction of the North China Craton （NCC）, has been carried out in the past few years by Chinese scientists through an in-depth ...and systematic observations, experiments and theoretical analyses, with an emphasis on the spatio-temporal distribution of the NCC destruction, the structure of deep earth and shallow geological records of the craton evolution, the mechanism and dynamics of the craton destruction. From this work the foUowing conclusions can be drawn： （1） Significant spatial heterogeneity exists in the NCC lithospheric thickness and crustal structure, which constrains the scope of the NCC destruction. （2） The nature of the Paleozoic, Mesozoic and Cenozoic sub-continental lithospheric mantle （CLM） underneath the NCC is characterized in detail. In terms of water content, the late Mesozoic CLM was rich in water, but Cenozoic CLM was highly water deficient. （3） The correlation between magmatism and surface geological response confirms that the geological and tectonic evolution is governed by cratonic destruction processes. （4） Pacific subduction is the main dynamic factor that triggered the destruction of the NCC, which highlights the role of cratonic destruction in plate tectonics.
The incidence of type 2 diabetic osteoporosis (T2DOP), which seriously threatens elderly people’s health, is rapidly increasing in recent years. However, the specific mechanism of the T2DOP is still ...unclear. Studies have shown the relationship between iron overload and T2DOP. Mitochondrial ferritin (FtMt) is a protein that stores iron ions and intercepts toxic ferrous ions in cells mitochondria. Ferroptosis, an iron-dependent cell injured way, may be related to the pathogenesis of T2DOP. In this study, we intend to elucidate the effect of FtMt on ferroptosis in osteoblasts and explain the possible mechanism. We first detected the occurrence of ferroptosis in bone tissue and the expression of FtMt after inducing T2DOP rat model. Then we used hFOB1.19 cells to study the influence of high glucose on FtMt, ferroptosis, and osteogenic function of osteoblasts. Then we observed the effect of FtMt on ferroptosis and osteoblast function by lentiviral silencing and overexpression of FtMt. We found ferroptosis in T2DOP rats bone. Overexpression of FtMt reduced osteoblastic ferroptosis under high glucose condition while silent FtMt induced mitophagy through ROS / PINK1/Parkin pathway. Then we found increased ferroptosis in osteoblasts after activating mitophagy by carbonyl cyanide-m-chlorophenyl-hydrazine (CCCP, a mitophagy agonist). Our study demonstrated that FtMt inhibited the occurrence of ferroptosis in osteoblasts by reducing oxidative stress caused by excess ferrous ions, and FtMt deficiency induced mitophagy in the pathogenesis of T2DOP. This study suggested that FtMt might serve as a potential target for T2DOP therapy.
Indian continental subduction can explain Cenozoic crustal deformation, magmatic activity and uplift of the Tibetan Plateau following the India-Asia collision. In the western Himalayan syntaxis and ...central Himalaya, subduction or underthrusting of the Indian Plate beneath the Eurasian Plate is well known from seismological studies. However, because information on the deep structure of the eastern Himalayan syntaxis is lacking, the nature of the Indian subduction slab beneath Myanmar and the related tectonic regime remain unclear. Here, we use receiver function common conversion point imaging from a densely spaced seismic array to detect direct structural evidence of present-day Indian continental subduction beneath Asia. The entire subducting Indian crust has an average crustal thickness of ~30 km, dips at an angle of ~19°, and extends to a depth of 100 km under central Myanmar. These results reveal a unique continental subduction regime as a result of Indian-Eurasian continental collision and lateral extrusion.
A detailed knowledge of the thickness of the lithosphere in the northeastern North China Craton (NCC) is important for understanding the significant tectonic reactivation of the craton in the ...Mesozoic and Cenozoic time. We achieve this goal by applying the newly proposed wave equation-based migration technique to the S-receiver functions recently collected in the region. Distinct negative signals are identified below the Moho in all the S-receiver function-migrated images and stacks, which we interpret as representing the S-to-P conversions from the lithosphere–asthenosphere boundary (LAB). The imaged LAB is as shallow as ∼60–70 km in the southeast basin and coastal areas and deepens to no more than 140 km in the northwest mountain ranges and continental interior. These observations indicate widespread lithospheric thinning in the study region in comparison with the >180-km lithospheric thicknesses typical of most cratonic regions. The revealed topography of the LAB generally agrees with the lateral variation in upper mantle seismic anisotropy previously measured through SKS splitting analysis. In particular, a sharp LAB step of ∼40 km is detected at the triple junction of the basin and mountains, at almost the same place where an abrupt change from NW–SE to NE–SW in fast polarization direction of shear waves was found. These findings suggest a close correlation between the seismic anisotropy and hence deformation of the upper mantle, the lithospheric thickness, and the surface tectonics of the northeastern NCC. While the thinned lithosphere and the NW–SE fast shear wave polarizations in the east areas probably are related to the dominant NW–SE tectonic extension in the late Mesozoic–Cenozoic time, the thicker lithosphere and the NE–SW fast polarization direction in the west mountain ranges may reflect earlier contractional deformations of the region. Synthetic tests indicate that the LAB beneath the northeastern NCC is a well-defined zone 10–20 km thick. Combined with seismic tomography results and geochemical and petrological data, this suggests that complex modification of the lithosphere probably accompanied significant lithospheric thinning during the tectonic reactivation of the old craton.
We apply the newly proposed wave equation‐based receiver function poststack migration method to the Northern China Interior Structure Project broadband data to image the lithospheric structure of the ...Tanlu Fault Zone area in eastern China. Our migration result reveals a 60‐ to 80‐km‐thick present‐day lithosphere beneath the study region, significantly thinned from the Paleozoic lithosphere of >180 km. The lithosphere‐asthenosphere boundary (LAB) is coherently imaged along the ∼300‐km east‐west profile, displaying an arc‐like shape with its apex roughly coincident with the transverse location of the Tanlu Fault Zone on the surface. An obvious uplift from ∼36 km to ∼32 km of the Moho is also clearly detected right below this fault zone. The coincidence of the imaged Moho uplift and the LAB apex with the surface location of the Tanlu Fault Zone provides seismological evidence for the steep geometry and deep penetration of the fault system, and indicates that the Tanlu Fault Zone might have acted as a major channel for anthenosphere upwelling during the Mesozoic‐Cenozoic continental extension and lithospheric thinning in eastern China. Frequency analysis and synthetic modeling suggest that both the Moho and the LAB are sharp and strong. The latter, in particular, is constrained to have a 3–7% drop in S wave velocity over a depth range of 10 km or less. Such a rapid velocity change at the base of the lithosphere in the study region cannot be solely explained by thermal variation, but likely reflects the presence of volatiles or melt in the asthenosphere, or is partially attributed to the compositional contrast between the preserved depleted and dehydrated cratonic lithospheric veneer and the uplifted hydrated and fertile asthenospheric materials.
Interaction between the subducting slab, the overriding continental lithosphere and mantle flow are fundamental geodynamic processes of subduction systems. Eastern China is an ideal natural ...laboratory to investigate the behavior and evolution of cratonic blocks within a subduction system. In this study, we investigate deformation of the upper mantle beneath eastern China. We present seismic shear wave splitting measurements from three networks consisting of over 483 broadband stations, with 157 stations giving a total of 516 results. The splitting parameters exhibit complex regional patterns but are relatively coherent within individual tectonic units. Tectonic blocks exhibited distinctive fast directions relative to regional features. The dominant attitude of fast directions for the North China Craton was subparallel to the direction of subduction, whereas fast directions for Southeastern China were perpendicular to the direction of subduction. The shear wave splitting measurements were interpreted according to a high resolution tomographic body-wave velocity model. Combining these two datasets showed that the predominant geodynamic models for the region (mantle plume, mantle wedge and flat-slab subduction models) are incompatible with the observations presented here. We suggest that the North China Craton, Yangtze Craton and the Cathaysia block have undergone different deformational events due to differing mantle flow patterns, and distinct spatial and temporal subduction histories of the Pacific and Philippine Sea plates.
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►High-resolution seismic shear wave splitting observations in eastern China. ►Distinct relationships between fast directions and tectonic units are discovered. ►Interpretation combining shear wave splitting measurements with tomographic model. ►Interplay of cratonic lithosphere and the subduction-induce flow was emphasized.
We present new 3‐D tomographic models of VP, VS and VP/VSratio anomalies in the upper mantle beneath EC and adjacent areas. This data was collected and interpreted with the goal of clarifying ...geodynamic processes that caused spatially variable event histories throughout Eastern China (EC) during Mesozoic to Cenozoic time. The tomographic images were constructed by inverting body wave travel‐times recorded at ∼1300 stations within the upgraded China National Seismic Network, and 9 temporary arrays. Resolution tests for different depths and the featured velocity anomalies verify that the tomographic images capture the velocity heterogeneities in the upper mantle to depths of 700 km. The salient features of VP, VS and VP/VSratio anomalies can be clearly identified. These include strong multiscale heterogeneities occupying the upper mantle beneath EC and differences in the spatial scale of anomalies found beneath northern and southern areas of EC. These features demonstrate a degree of spatial variability in the geodynamic evolution of EC. We propose two mechanisms to explain these patterns. First, the western front of the subducted slab may have imparted greater horizontal compressional stress in areas where it impinged further eastward into EC. These areas would experience stronger convection and an altered stress regime in the upper mantle, creating significant thermal anomalies beneath the South China Block (SCB) relative to the eastern North China Craton (NCC). Second, differing thermal states and viscosities for the eastern NCC and the Cathaysia Block (CaB) resulted in differing responses to regional deformation. The Archean hinterland of the eastern NCC specifically has a colder thermal state and higher viscosity, and therefore exhibits only small‐scale heterogeneities due to the effect of shear localization. The Neoproterozoic CaB has a relatively warm thermal state with lower viscosity, and thus deformed more continuously.
Key Points
First tomographic models of Vp, Vs, Vp/Vs in upper mantle beneath east China
Strong multi‐scale heterogeneities occupy the upper mantle in eastern China
Strong contrast in spatial scale of anomalies from north to south in east China
Due to the difficulty in generating a 6-Degree-of-Freedom (6-DoF) object pose estimation dataset, and the existence of domain gaps between synthetic and real data, existing pose estimation methods ...face challenges in improving accuracy and generalization. This paper proposes a methodology that employs higher quality datasets and deep learning-based methods to reduce the problem of domain gaps between synthetic and real data and enhance the accuracy of pose estimation. The high-quality dataset is obtained from Blenderproc and it is innovatively processed using bilateral filtering to reduce the gap. A novel attention-based mask region-based convolutional neural network (R-CNN) is proposed to reduce the computation cost and improve the model detection accuracy. Meanwhile, an improved feature pyramidal network (iFPN) is achieved by adding a layer of bottom-up paths to extract the internalization of features of the underlying layer. Consequently, a novel convolutional block attention module-convolutional denoising autoencoder (CBAM-CDAE) network is proposed by presenting channel attention and spatial attention mechanisms to improve the ability of AE to extract images' features. Finally, an accurate 6-DoF object pose is obtained through pose refinement. The proposed approach is compared to other models using the T-LESS and LineMOD datasets. Comparison results demonstrate the proposed approach outperforms the other estimation models.
Gas chromatography-mass spectroscopy (GC–MS) and highly selective and sensitive gas chromatography–triple quadrupole mass spectrometry (GC–MS–MS) detections were applied to investigate low molecular ...weight polycyclic aromatic hydrocarbons (PAHs; alkylnaphthalenes, alkylphenanthrenes, and alkyldibenzothiophenes) variations and quantify diamondoids (adamantanes and diamantanes) on a set of coal-bearing Longtan Shale samples within the thermal maturity range of 1.53–3.38%VRr (random vitrinite reflectance). Under consideration of pyrolytic results of kerogen (type I, II, and III), source rock extracts, and oil, the following conclusions were drawn: 1) Poor correlation was observed between PAH isomerization ratios and vitrinite reflectance, which suggests that they are not primarily dependent on thermal maturity. 2) The yield peaks of both adamantanes and diamantanes occur at the maturity of 1.74%VRr; the adamantanes concentration increases and sharply exhausts thereafter, whereas the amount of diamantanes reduces gradually with increasing maturity after the yield peak. 3) Diamondoids concentration and isomerization indices show a significant dependency depend on thermal maturity; adamantanes-related maturity indices show positive correlations with increasing thermal maturity up to 3.0%VRr and reverse correlations after that, whereas diamantanes indices show the reverses later than 3.0%VRr. 4) The distributions of aromatic isomers are affected by organic matter types, while the isomerization indices of diamondoids seem independent of organic matter origin. 5) Clay minerals can catalyze the degree of isomerization of alkylphenanthrenes and adamantanes, and enhance the yield of diamondoids at maturities <1.80%VRr; while mineral compositions have minor effects at maturities higher than 2.53%VRr. 6) The total sulfur content has little effect on the variation of aromatics maturity indices and diamondoids yields. Sulfur-derived dealkylation, however, should be considered in the evaluation of methyl adamantanes and ethyl adamantanes. Consequently, diamondoids concentration and isomerization indices may serve as stronger maturity indicators than low PAHs isomerization ratios at the mature to overmature stage.
•PAHs variations investigation and diamondoids quantification by GC–MS and GC–MS-MS.•Organic matter type and clay content control PAHs isomerization at overmature stage.•Yield distributions of naturally matured samples are compared with kerogen, extracts, and oil.•Diamondoids yields and distributions are controlled by mineral composition and TS.
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