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The Coexisting Clinopyroxene-Garnet Acidometer and Acidity Facies of Skarn Deposits

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Acta Geologica sinica(english Edition) 1990年第3期64卷 299-308页

作者： Lin Wenwei institute of Mineral Deposits, chinese academy of geological sciences, beijing liu linqun institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing

On the basis of geological studies of skarn deposits in China and by using thermodynamic models of thesolid solution, the coexisting clinopyroxene-garnet pair in skarn deposits has been analysed and a coexistingclinopyroxene-garnet acidometer developed. They can be used to estimate the medium condition under whichthe skarn was formed. The research on the acidity for the formation of various metallic skarn deposits in Chinasuggests that skarns endowed with dissimilar types of mineralization and occurring in diverse environments dif-fer in the acidity conditions for their formation and in the trend of acidity variation of ore-bearing fluid. This,coupled with the study of oxygen fugacity of coexisting minerals, makes it possible to establish the oxygenfugacity-acidity facies of skarn deposits, which reflect the close genetic relationship between the metallizationand the formation of skarn.

关键词： OH The Coexisting Clinopyroxene-Garnet Acidometer and Acidity Facies of Skarn Deposits

Discovery of Fossil Charophytes from the Late Triassic Xujiahe Formation and Early Jurassic Lower Yimen Formation, sichuan Province, and Its significance

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Acta Geologica sinica(english Edition) 1992年第3期66卷 301-309,327页

作者： liu Junying Chen Zhongliang institute of geology, chinese academy of geological sciences, beijing Panxi geological Party, sichuan Bureau of geology and Mineral Resources, Xichang liu linqun institute of geology Chinese Academy of Geological Sciences Beijing China

This paper describes the fossil charophytes collected from the Late Triassic Xujiahe Formation in Dazuand Early Jurassic Lower Yimen Formation in Xichang, sichuan Province, and their significance. Up to now,papers dealing with fossil charophytes of the Late Triassic, especially of the Early Jurassic, have been rarelypublished. The description of the two new species of Porochara, P. dazuensis and P. xichangensis, and theirfossil assemblage not only provides an important basis for classification and correlation of red beds insouthwestern China but reveals for the first time the features of the charophyte flora of the Late Triassic-EarlyJurassic in the area, thus offering valuable data for the establishment of Triassic and Jurassic charophyte fossilzones in China.

关键词： sichuan Late Triassic Early Jurassic charophyte fossil

geological Setting of the Porphyry Copper Deposit Series of China

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Acta Geologica sinica(english Edition) 1992年第1期66卷 59-73页

作者： Zhang Hongtao Rui Zongyao institute of Mineral Deposits, chinese academy of geological sciences, beijing liu linqun institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing

In accordance with the terms global minerogenic series, regional metallogenic series and ore depositsystem which are put forward here, metallogenic environments at different levels are discussed for theporphyry copper deposit series in China. It is considered that the porphyry copper deposits in China arecontrolled not only by the boundaries of convergent plates but, more importantly, by the boundaries ofintraplate divergent mobile belts and those between continental blocks. Besides, the emplacement ofhypabyssal and supper-hypabyssal calc-alkaline magmas and the temporal-spatial distribution of China'sporphyry copper deposits are governed by the superimposition of fracture systems of the pre-Alpine base-ments. Meso-Cenozoic cover and continental-margin new-born crust. Such a superimposition has also re-sulted in the polycyclicity of the mineralization.

关键词： Zhang geological Setting of the Porphyry Copper Deposit Series of China

Ordovician-silurian Boundary Extinction and Its Relationship to Iridium and carbon Isotope Anomalies

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Acta Geologica sinica(english Edition) 1990年第1期64卷 81-92页

作者： wang Xiaofeng Chai Zhifang Yichang institute of geology and Minieral Resources, chinese academy of geological sciences, Yichang. Hubei institute of High energy, Academia sinica, beijing liu linqun Yichang institute of geology and Mineral Resources Chinese Academy of Geological Sciences Yichang Hubei China

The abundance distributions of more than 40 elements in the No. 502 Ordovician-silurian (O/S) bounda-ry section at Fenxiang, Yichang have been studied by RNAA and INAA. The results show that in the bounda-ry bed, there is a distinctive Ir anomaly because the Ir concentration abruptly increases to 0.64 ppb.Furthermore, the Ir is positively correlated in abundance variation with some siderophile and sulphophile ele-ments. In the same bed of the O/S boundary section at Huanghuachang, Yichang, there is also a δ^(13)C excur-sion. These geochemical signs support the hypothesis that the terminal Ordovician mass extinction was proba-bly related to extraterrestrial event, and provide new evidence for defining the O/S boundary between theHirnantia-Kinnella and G. persculptus Zones.

关键词： Ordovician-silurian Boundary Extinction and Its Relationship to Iridium and carbon Isotope Anomalies Chen wang

Evolution of Apatites in the Diagenesis

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Acta Geologica sinica(english Edition) 1990年第2期64卷 147-162,233+236页

作者： liu Kuiwu institute of geology, Academia sinica, beijing liu linqun chinese academy of geological sciences Beijing

Apatites occurring in sedimentary rocks are carbonate fluorapatites (C-F apatites) with differentCO_2 contents. During diagenesis. the CO_2 in the C-F apatites gradually decreased with the increasing strengthof diagenesis. resulting in the systematic changes in refractive index. specific gravity, cell parameters and crystalchemistry of apatites. On the basis of X-ray diffraction and IR spectroscopic analyses, the author proposes twoparameters for determining diagenetic stages. i.e.. the crystallinity index (CR) and sharpness index (SH). Thesetwo parameters serve as new criteria for the determination. which due to the common existence of phosphorousnodules and bands and argillo-crystalline cement in sedimentary rocks, most likely have wide prospects for ap-plication.

关键词： Evolution of Apatites in the Diagenesis

SHRIMP zircon U-Pb geochronology of early Mesozoic felsic igneous rocks from the southern Lancangjiang and its tectonic implications

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Science China Earth sciences 2006年第10期49卷 1032-1042页

作者： PenG Touping1,2, wang Yuejun1, FAN Weiming1, liu Dunyi3, SHI Yuruo3 & MIAO Laicheng4 1. Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou institute of Geochemistry, chinese academy of sciences, Guangzhou 510640, China 2. Graduate University of chinese academy of sciences, beijing 100039, China 3. SHRIMP isotope Laboratory, chinese academy of geological sciences, beijing 100037, China 4. institute of geology and Geophysics, chinese academy of sciences, beijing 100029, China Key Laboratory of Isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Graduate University of chinese academy of sciences Beijing China SHRIMP isotope Laboratory Chinese Academy of Geological Sciences Beijing China institute of geology and Geophysics Chinese Academy of Sciences Beijing China

The SHRIMP zircon U-Pb geochronology of three typical samples, including two monzo nitic granites from the Lincang batholith and a rhyolite from the Manghuai Formation are presented in the southern Lancangjiang, western Yunnan Province. The analyses of zircons for the biotite monzonitic granites from the northern (02DX-137) and southern (20JH-10) Lincang batholith show the single and tight clusters on the concordia, and yield the weighted mean 206Pb/238U ages of 229.4 ± 3.0 Ma and 230.4 ± 3.6 Ma, respectively, representing the crystallized ages of these granites. The zircons for the rhyolitic sample (02DX-95) from the Manghuai Formation give a weighted mean 206Pb/238U age of 231.0 ± 5.0 Ma. These data suggest that the igneous rocks from the Lincang granitic batholith and Manghuai Formation have a similar crystallized age. In combination with other data, it is inferred that both were generated at a narrow age span (~230 Ma) and were originated from the postcollisional tectonic regime. An early Proterozoic 206Pb/238U apparent age of 1977±44 Ma is additionally obtained from one zircon from the biotite monzonitic granite (southern Lincang batholith), indicative of devel- opment of the early Proterozoic Yangtze basement in the region. These precisely geochronological data provide important constraints on better understanding the Paleozoic tectonic evolution of the Tethys, western Yunnan Province.

关键词： SHRIMP zircon U-Pb dating, Middle Triassic, Lincang granitic batholith, Manghuai Formation rhyolite, southern Lancangjiang.

Creep constitutive model considering nonlinear creep degradation of fractured rock

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International Journal of Mining Science and Technology 2024年第1期34卷 105-116页

作者： wang Chunping liu Jianfeng Chen Liang liu Jian wang Lu Liao Yilin beijing Research institute of Uranium geology Beijing 100029China CAEA Innovation Center for geological Disposal of High-Level Radioactive Waste Beijing 100029China State Key Laboratory of Hydraulics and Mountain River engineering Sichuan UniversityChengdu 610065China School of Architecture and Civil engineering Xihua UniversityChengdu 610039China

Stability analysis of underground constructions requires a model study of rock masses’ long-term performance. Creep tests under different stress conditions was conducted on intact granite and granite samples fractured at 30° and 45° angles. The experimental results indicate that the steady creep strain rates of intact and fractured rock present an exponential increase trend with the increase of stress level. A nonlinear creep model is developed based on the experimental results, in which the initial damage caused by fracture together with the damage caused by constant load have been taken into consideration. The fitting analysis results indicated that the model proposed is more accurate at identifying the full creep regions in fractured granite, especially the accelerated stage of creep deformation. The least-square fit error of the proposed creep model is significantly lower than that of Nishihara model by almost an order of magnitude. An analysis of the effects of elastic modulus, viscosity coefficient, and damage factors on fractured rock strain rate and creep strain is conducted. If no consideration is given to the effects of the damage, the proposed nonlinear creep model can degenerate into to the classical Nishihara model.

关键词： Fractured rock Damage Creep Beishan granite geological disposal

Primary Study on Quantitative Reconstruction of Middle-Late Eocene Climate in Jianghan Basin

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Journal of China University of Geosciences 2002年第3期13卷 252-259页

作者： Tong Guobang liu Zhiming institute of Hydrogeology and environmental geology, chinese academy of geological sciences, Zhengding 050803 Open Laboratory of Saline Lake Resources and environment, chinese academy of geological sciences, beijing 100037 Zheng Mianping institute of Mineral Resources, chinese academy of geological sciences, beijing 100037 Research & Development Center of Saline Lake and Epithermal Deposit, chinese academy of geological sciences, beijing 100037 wang Weiming Nanjing institute of geology and Palaeontology, chinese academy of sciences, Nanjing 210008 institute of Hydrogeology and environmental geology Chinese Academy of Geological Sciences Zhengding 050803 Open Laboratory of Saline Lake Resources and environment Chinese Academy of Geological Sciences Beijing 100037 institute of Mineral Resources Chinese Academy of Geological Sciences Beijing 100037 Research & Development Center of Saline Lake and Epithermal Deposit Chinese Academy of Geological Sciences Beijing 100037 Nanjing institute of geology and Palaeontology Chinese Academy of Sciences Nanjing 210008

This paper reports our primary effort in the quantitative reconstruction ofpaleoclimate based on the thrine in phytoecology of the affinity parent plants in the stratigraphicpollen records. The Eocene pollen data come from our former study on the Mingjia borehole 1 in theJianghan basin. The fluctuating trend in the parameter curve of climate shows that the climate inthe Middle Eocene in the Jianghan basin was more or less comparable with that of the present22°―26°N, characteristic of a humid, semi-humid central-southern subtropical climate. The annualtemperature at that time dropped by 1 ℃― 4 ℃ in the Late Eocene, approximately equal to that ofthe present 23°―28°N of northern-central subtropical climate. However, the climate composite atthat time, characterized by higher temperature, small annual range and big fluctuation inprecipitation, was quite different from the present one. The average temperature in January in theMiddle Eocene, higher than that of today, ranged between 5 ℃ and 9 ℃, indicating that no effect ofwinter monsoon occurred in the Middle Eocene, though such an effect may have occurred occasionallyin the Late Eocene. Major temperature decline is recognized at the depth of 2 100 m in the borehole,as was indicated by the decline in average January temperature, the increase in annual range, andthe increase in the deciduous broad-leaved types of trees in the spore-pollen assemblage. The sharpfluctuation in the annual precipitation, usually raging from 300 to 1 700 mm, was favorable for themigration and accumulation of salty deposit. When the precipitation was lower than 1 000 mm,ephemera shrub increased at the same depth as that of the salty deposit. It is, therefore, deducedthat the formation of the salty deposit was attributed mainly to the dry and hot environment in thehigh mountains and deep basins. The small annual precipitation and the intense fluctuation arefavorable for the sustainable accumulation of the salts, which is different from the present

关键词： quantitative reconstruction of paleoclimate annual range function ofthrine in phytoecology fuzzy mathematics eocene jianghan basin

Three dimensional velocity model and its tectonic implications at China Seismic Experimental site,eastern margin of the Tibetan Plateau

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Science China Earth sciences 2024年第7期67卷 2268-2290页

作者： Jianping WU Yan CAI Wei wang Weilai wang Changzai wang Lihua FANG Yaning liu Jing liu institute of Geophysics China Earthquake AdministrationBeijing 100081China beijing Baijiatuan Earth Science National Observation and Research Station Beijing 1095China beijing Earthquake Agency Beijing 100080China

The China Seismic Experimental site(CSES)is located at the intersection of the Tibetan Plateau,South China Block,and Indian Plate and has complex geological settings and intense crustal deformation,making it one of the most seismically active areas in chinese mainland.A high-resolution,three-dimensional(3D)crust-mantle velocity structure is crucial for understanding seismotectonic environments,lithospheric deformation mechanisms,and deep dynamic *** first constructed a high-vertical-resolution 3D initial velocity model using the joint inversion of receiver functions and surface waves and then obtained a 3D P-and S-wave velocity model(CSES-VM1.0)with the highest lateral resolution of 0.25°for the CSES using double-difference *** to the limitations of the Sn observation data,the resolution of the S-wave velocity model in the lower crust and upper mantle was reduced,making it closer to the initial model provided by joint inversion.A comparison with explosive-source seismic data showed that the synthetic P-wave first-arrival travel times of the new model were closer to the observations than those of the previous velocity *** velocity cross-sections across the source areas of the 2022 Lushan MS6.1 and Ludian MS6.8 earthquakes reveal that the former earthquake occurred near a weak contact zone between the Tibetan Plateau and sichuan Basin,and the rupture of the latter earthquake occurred in a granitic area,with the northern end blocked by rigid high-velocity bodies.A clear high-velocity anomaly zone is distributed along the western margin of the Yangtze Block,revealing the spatial distribution of Neoproterozoic intermediate-basic *** high-velocity zone significantly controls the morphology of fault zones and influences the rupture processes of major *** northeast-southwest and north-south trending high-velocity anomalies were found near Panzhihua,potentially related to Neoproterozoic and Middle-Late Permian intermediate

关键词： Eastern Tibetan Plateau China Seismic Experimental site Yangtze Block Velocity model Double-difference tomography