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South China's Gondwana connection in the Paleozoic:Paleomagnetic evidence

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Progress in Natural Science:Materials International 2004年第1期14卷 86-91页

作者： ZHANG Shihong*(school of Earth Sciences and Resources, China University of geosciences, Beijing 100083, China) China Univ geosci Sch Earth Sci & Resources Beijing 100083 Peoples R China

The reconstruction in which the South China Block (SCB) lies along the Great India Australia region of Gondwana margin is tested by using existing Paleozoic paleomagnetic data. Under the proposed reconstruction, all six high quality paleopoles from the SCB between the Early Cambrian and late Early Devonian (～400 Ma) are in good agreement with coeval paleopoles from Gondwana. Thereafter, the apparent polar wander paths for the SCB and Gondwana diverge markedly. This indicates that the SCB had been part of Gondwana and the connection was intact from at least Early Cambrian until late Early Devonian, but they began to separate by late Middle Devonian (～375 Ma).

关键词： South China block Gondwana paleomagnetism reconstruction

Electron microscopy study of the sakhaite from endogenous borate deposit in Hunan, China

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Science China Earth Sciences 2004年第3期47卷 232-238页

作者： LIU Xiangwen1,2, YANG Guangming2, ZOU Huamin3, QU Jing1 & ZHAO Wenxia4 1. Graduate school, China University of geosciences, Wuhan 430074, China 2. Test Center, China University of geosciences, Wuhan 430074, China 3. physics and Technology College, Wuhan University, Wuhan 430072, China 4. Test Center, Zhongshan University, Guangzhou 510275, China China Univ geosci Grad Sch Wuhan 430074 Peoples R China China Univ geosci Test Ctr Wuhan 430074 Peoples R China Wuhan Univ Phys & Technol Coll Wuhan 430072 Peoples R China Zhongshan Univ Test Ctr Guangzhou 510275 Peoples R China

Sakhaite specimens from an endogenous borate deposit in Hunan Province, China have been studied in detail by means of transmission electron microscopy (TEM). The selected area electron diffraction (SAED) patterns obtained with different crystal zone axes show that the crystal system is cubic, with a = 1.463 nm. The convergent beam electron diffraction (CBED) patterns indicate that the point group and space group of sakhaite is m3m and Fd3m, respec-tively. The space group of synthetic sakhaite determined by Chichagov (1974) is F4132. The possible reasons why the space groups of the natural and the synthetic sakhaites are different are discussed.

关键词： sakhaite, space group, convergent beam electron diffraction (CBED).

Microcosmic analysis of ductile shearing zones of coal seams of brittle deformation domain in superficial lithosphere

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Science China Earth Sciences 2004年第5期47卷 393-404页

作者： JU Yiwen1,2, WANG Guiliang2, JIANG Bo2 & HOU Quanlin1 1. Graduate school, Chinese Academy of Sciences, Beijing 100039, China 2. College of Mineral Resources and geosciences, China University of Mining & Technology, Xuzhou 221008, China Chinese Acad Sci Grad Sch Beijing 100039 Peoples R China China Univ Min & Technol Coll Mineral Resources & Geosci Xuzhou 221008 Peoples R China

The ductile shearing zones of coal seams in a brittle deformation domain in super-ficial lithosphere are put forward based on the study on bedding shearing and ductile rheology of coal seams. The macrocosmic and microcosmic characteristics include wrinkle fold, mymonitized zones and ductile planar structure of coal seams, etc., while the microcosmic characteristics may also include different optic-axis fabrics and the anisotropy of vitrinite reflectance as well as the change of chemical structure and organic geochemistry components. The forming mechanism is analyzed and the strain environment of ductile shearing zones of coal seams discussed. The result indicates that, in the superficial brittle deformation domain, the coal seams are easy to be deformed, resulting in not only brittle deformation but also ductile shearing deformation under the action of force. Because of simple shearing stress, the interlayer gliding or ductile rheology may take place between coal seams and wall rocks. Therefore, many ductile shearing zones come into being in superficial lithosphere (<5 km). The research on ductile shearing zone of brittle de-formation domain in superficial lithosphere is significant not only theoretically for the study of ductile shearing and ductile rheology of the lithosphere but also practically for the structural movement of coal seams, the formation and accumulation of coal-bed methane, and the preven-tion and harness of gas burst in coal mine.

关键词： brittle deformation domain, interlayer gliding, ductile rheology, ductile shearing zones of coal seams, coal mymonite, vitrinite reflectance anisotropy.

Indentation Size Effect on the Mechanical Properties of Supersonic Plasma Sprayed NiCr-Cr_3C_2 Coating

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稀有金属材料与工程 2012年第S1期41卷 296-298页

作者： Zhu Lina1,2,Xu Binshi2,Wang Haidou2,Wang Chengbiao1 1 school of Engineering and Technology,China University of geosciences,Beijing 100083,China 2 National Key Laboratory for Remanufacturing,Academy of Armored Forces Engineering,Beijing 100072,China Acad Armored Forces Engn Natl Key Lab Remfg Beijing 100072 Peoples R China China Univ geosci Sch Engn & Technol Beijing 100083 Peoples R China

In this paper,NiCr-Cr3C2 coating was deposited onto AISI 1045 steel substrate by employing supersonic plasma spraying *** surface and cross-section morphologies of the NiCr-Cr3C2 coating were observed by *** phase constituents of the coating were identified by *** SEM images showed that the coating was very dense,and it had a low porosity *** XRD pattern implied that the coating was mainly composed of NiCr,Cr3C2 and *** tests were performed on the coating surface by a Nano *** widely used Oliver-Pharr method was adopted to extract the mechanical properties of the *** hardness exhibited a strong peak-load-dependence,*** size effect;the elastic modulus was not affected by indentation size effect.

关键词： nanoindentation mechanical property indentation size effect

On the siltation of the middle Yangtze River

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Science China Earth Sciences 2004年第5期47卷 463-480页

作者： YIN Hongfu1, CHEN Guojin2, LI Chang抋n1 & WEI Yuan3 1. school of Earth Sciences, China University of geosciences, Wuhan 430074, China 2. Hydrogeological Team, Hubei Bureau of Geology and Mineral Resources, Jingzhou 434100, China 3. Geological Survey of Jiangxi Province, Nanchang 330201, China China Univ geosci Sch Earth Sci Wuhan 430074 Peoples R China Hubei Bur Geol & Mineral Resources Hydrogeol Team Jinzhou 434100 Peoples R China Geol Survey Jiangxi Province Nanchang 3300201 Peoples R China

About 5.2×108 t/a of silts from the upper reach of the Yangtze River are transported through Yichang into the middle Yangtze River. The middle Yangtze itself and its tributaries yield ca. 0.8×108 t silts annually. Of this total 6×108 t/a input of silts, ca. 1.2×108 t/a are deposited within the river artery and lakes, while ca 4.83×108 t/a are at first transported into the lower reach through Datong, and then either deposited along the river and the Yangtze Delta, or output into the sea. Along the middle Yangtze River silting generally exceeds scouring, but the spatial and temporal distributions of scour-and-fill, as well as its distribution in the river valley transections, are uneven. Along the Yichang-Chenglingji and Jiujiang-Datong Segments of the middle Yangtze, scouring exceeds or equals silting. Silting mainly occurs along the Luoshan-Wuhan-Huangshi Segments with Wuhan as the pivotal point, as well as in the Dongting and Poyang Lakes. Even in these silting-dominated areas, there are times and parts of segments that scouring prevails. As to the transections, generally the river channel of main stream is scouring-dominated, forming V-shaped sections to a depth of 2030 m or more, whereas the floodplains and bar islands are silting-dominated, forming wide and relatively high flats, which are often artificially transformed into protected embankments. Because the Jingjiang Levee separates the Jianghan Plain from Yangtze to the south, little has been deposited in that plain except a few sediments from the Han River—a tributary of the middle Yangtze. This factor plus the tectonic sag of that plain has made the altitude of plain surface several meters lower than that of the levee in most of the areas. Sil-tation along the Luoshan-Wuhan-Huangshi Segments has resulted in the elevation of flood level in this and upstream segments. River channel scouring plus floodplain silting have caused the transections of the middle Yangtze valley typically with deep channel and height

关键词： the middle Yangtze, scour-and-fill, siltation, silt utilization.

Investigation of rockfall-prone road cut slope near Lengpui Airport,Mizoram,India

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 146-158页

作者： A.K.Verma Sahil Sardana Pushpendra Sharma Lal Dinpuia T.N.Singh Department of Mining Engineering Indian Institute of Technology (Banaras Hindu Universiy) Department of Mining Engineering Indian Institute of Technology (Indian School of Mines) Department of Civil Engineering Lassonde School of Engineering York University Department of Ceology Pachhunga University College Department of Earth Sciences Indian Institute of Technology Bombay

Rockfall is one of severe natural hazards that are frequently reported in northeast region of India. It carries rock block falling from the cliff with high velocities and energies which can result in damages to vehicles, disruption to transportation, injuries and fatalities. The massive rockfall event which occurred in April 2017 on the highway NH-44 A, near Lengpui Airport, blocked the traffic for 1 d, and fortunately,no casualties were reported as the event occurred in the night. This is the only highway connecting the Aizawl city to the airport and the region is highly prone to rockfall events. Hence assessment of rockfall along this highway is necessary. In the current study, rockfall hazard assessment has been carried out on three locations by rockfall hazard rating system(RHRS). During pre-failure analysis, the result shows that most hazardous slopes have RHRS score of 639. The slopes were found to be vulnerable and later on the rockfall activity occurred. Three-dimensional(3 D) stability analysis has been carried out using 3 DEC software package to analyze the failure behavior and to decide the rockfall-prone zone(unstable blocks)for slope. The total displacement of 2.24 cm and velocity of 2,25 mm/s of the failed block have been observed in the numerical analysis. Further, the rockfall vulnerable zone(unstable blocks) is considered to determine the parameters such as run-out distance, bounce height and energies of the falling rock blocks. The maximum total kinetic energy of 5047 kJ has been observed in the numerical analysis with the maximum run-out distance up to 18 m.

关键词： Rockfall hazards Rockfall simulation Rockfall hazard rating system(RHRS) Road cut slopes Slope stability

An Early Cretaceous Avialian Bird, Shenzhouraptor sinensis from Western Liaoning, China

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Acta Geologica Sinica(English Edition) 2003年第1期77卷 21-27页

作者： Ji Qiang, Ji Shu’an, You Hailu, Zhang Jianping,Zhang Hongbin, Zhang Nanjun, Yuan Chongxi and Ji XinxinDepartment of Earth Sciences, Nanjing University, Nanjing, Jiangsu 100093Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037 school of Earth and Space Sciences, Peking University, Beijing 100871China University of geosciences, Beijing 100083 China Dinosaur Park of Changzhou, Changzhou, Jiangsu 213002 Nanjing Univ Dept Earth Sci Nanjing 100093 Jiangsu Peoples R China Chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China Peking Univ Sch Earth & Space Sci Beijing 100871 Peoples R China China Univ geosci Beijing 100083 Peoples R China China Dinosaur Pk Changzhou Changzhou 213002 Jiangsu Peoples R China

This paper describes an avialian bird from the Early Cretaceous JiufotangFormation in Yixian county, western Liaoning China, which is named as Shenzhouraptor sinensis by Jiet al. on July 15, 2002. Shenzhouraptor sinensis is characterized by no teeth in its mouth, theforelimbs longer than the hindlimbs, a long tail with more than 23 caudal vertebrae, U-shapedwishbone, and remiges longer than the total length of ulna and manus. It is certain that the newavialian bird is really capable of powerful flight, representing a missing link between theropoddinosaurs and birds.

关键词： Avialian birds Early Cretaceous Jiufotang Formation western Liaoning China

Carbon dioxide emissions from the Three Gorges Reservoir,China

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Acta Geochimica 2017年第4期36卷 645-657页

作者： Shuang Li Fushun Wang Wenyun Luo Yuchun Wang Bing Deng school of Environmental and Chemical Engineering Shanghai University Department of Water Environment China Institute of Water Resources and Hydroelectric Power Research State Key Laboratory of Estuarine and Coastal Research East China Normal University

Carbon dioxide(CO_2) emission from the rivertype reservoir is an hotspot of carbon cycle within inland waters. However, related studies on the different types of reservoirs are still inadequate. Therefore, we sampled the Three Gorges Reservoir(TGR), a typical river-type reservoir having both river and lake characteristics, using an online system(HydroCTM/CO_2) and YSI-6600v2 meter to determine the partial pressure of carbon dioxide(pCO_2)and physical chemical parameters in 2013. The results showed that the CO_2 flux from the mainstream ranged from 26.1 to 92.2 mg CO_2/m^2h with average CO_2 fluxes of 50.0 mg/m^2h. The CO_2 fluxes from the tributary ranged from-10.91 to 53.95 mg CO_22/mh with area-weighted average CO_2 fluxes of 11.4 mg/m^2h. The main stream emits CO_2 to the atmosphere the whole year; however, the surface water of the tributary can sometimes act as a sink of CO_2 for the atmosphere. As the operation of the TGR, the tributary became more favorable to photosynthetic uptake of CO_2 especially in summer. The total CO_2 flux was estimated to be 0.34 and 0.03 Tg CO_2/year from the mainstream and the tributaries, respectively. Our emission rates are lower than previous estimates, but they are in agreement with the average CO_2 flux from temperate reservoirs estimated by Barros et al.(Nat geosci 4(9):593–596, 2011).

关键词： C02 emissions Three Gorges Reservoir River-type reservoir

A new cache of Eoarchaean detrital zircons from the Singhbhum craton,eastern India and constraints on early Earth geodynamics

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geoscience Frontiers 2019年第4期10卷 1359-1370页

作者： Bulusu Sreenivas Sukanta Dey Y.J. Bhaskar Rao T. Vijaya Kumar E.V.S.S.K. Babu Ian S. Williams CSIR-National Geophysical Research Institute Hyderabad 500007India Department of Earth Sciences Indian Institute of Science Education and ResearchKolkata 741246India Research school of Earth Sciences The Australian National UniversityCanberra 2601Australia

The dominant geodynamic processes that underpin the formation and evolution of Earth’s early crust remain enigmatic calling for new information from less studied ancient cratonic ***,we present U-Pb ages and Hf isotopic compositions of detrital zircon grains from^2.9 Ga old quartzites and magmatic zircon from a 3.505 Ga old dacite from the Iron Ore Group of the Singhbhum craton,eastern *** detrital zircon grains range in age between 3.95 Ga and 2.91 *** with the recently reported Hadean,Eoarchean xenocrystic(up to 4.24 Ga)and modem detritus zircon grains from the Singhbhum craton,our results suggest that the Eoarchean detrital zircons represent crust generated by recycling of Hadean felsic crust formed at^4.3-4.2 Ga and^3.95 *** observe a prominent shift in Hf isotope compositions at^3.6-3.5 Ga towards super-chondritic values,which signify an increased role for depleted mantle and the relevance of plate *** Paleo-,Mesoarchean zircon Hf isotopic record in the craton indicates crust generation involving the role of both depleted and enriched mantle *** infer a short-lived suprasubduction setting around^3.6-3.5 Ga followed by mantle plume activity during the Paleo-,Mesoarchean crust formation in the Singhbhum *** Singhbhum craton provides an additional repository for Earth’s oldest materials.

关键词： U-Pb zircon ages Hf isotopes Singhbhum craton Hadean Eoarchean Geodynamics