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TOPOLOGICAL CONFIGURATIONS OF POSSIBLE REAL NETS IN BINARY n+m(m≥3) PHASE MULTISYSTEMS

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science in china,Ser.B 1986年第10期29卷 1096-1109页

作者：程伟基 department of earth and space sciences university of science and technology of china hefei

This paper further summarizes the method and results developed to find all possible real nets in binary n+3 phase multisystems, and emphasizes that there is a definite relationship between configurations and symbols of stable and metastable invariant points of nets or positions of phases as symbols on the chemographic bar. On the basis of these, a general principle is developed to construct and check possible neets in binary n+m (m>3) phase multisysterns: this sort of nets must be the reasonable combination of one or more than one distinct binary n+3 phase multisystem subnets, in which the number of points missing respectively same m—3 phases in n+3. Therefore, the binary n-4.3 phase nets are basic construction units of the binary n+m(m>3) phase nets. As an instance, the maximum partially closed net in binary n+4.phase multisystems, which has the most stable invariant points, is constructed, and it is indicated that this sort of net is unique.

关键词： PHASE MULTISYSTEMS TOPOLOGICAL CONFIGURATIONS OF POSSIBLE REAL NETS IN BINARY n+m net NETS

Re-Os isotopic system and formation age of subcontinental lithosphere mantle

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Chinese science Bulletin 2000年第3期45卷 193-200页

作者： ZHI Xiachendepartment of earth and space sciences, {4. of science and technology of china, hefei 23.026, china Advance Research Center for earth science and Astronomy, USTC, Third World Academy of science, hefei 23.026, china Laboratory of Chemical Geodynamics, USTC, hefei 23.026, china department of earth and space sciences University of Science and Technology of China Hefei China Advance Research Center for earth science and Astronomy USTC Third World Academy of Science Hefei China Laboratory of Chemical Geodynamics USTC Hefei China

The determination of the formation age of subcontinental Lithosphere Mantle (SCLM) is a widely concerned issue in mantle geochemistry. it is difficult to obtain the formation age of SCLM using lithophile isotopic systems such as Rb-Sr, Sm-Nd, U-Th-Pb, ete., but as siderophile elements, the Re-Os isotopic system provides a powerful tool for that work. Here a comprehensive review on the recent development in Re-Os dating for SCLM has been given.

关键词： Re-Os isotopic dating subcontinental lithospheric mantle mantle derived peridotites Re depleted model age whole rock isochronological age.

The Thermal History of the Huangmeijian Granite Intrusion in Anhui and Its Relation to Mineralization: Isotopic Evidence

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Acta Geologica Sinica(English Edition) 1996年第2期70卷 168-180页

作者： Zheng Yongfei Fu Bin and Gong Bing department of earth and space sciences, {4. of science and technology of china, hefei 23.026 Liu Xinzhu department of earth and space sciences University of Science and Technology of China Hefei 230026

Whole-rock Rb-Sr, zircon U-Pb and hornblende, biotite and K-feldspar K-Ar ages areused to reconstruct the cooling history of the Huangmeijian intrusion in the Anqing-Lujiangquartz-syenite belt in Anhui. Oxygen isotope geothermometry of mineral pairs demonstrates thatdiffusion is a dominant factor controlling the closure of isotopic systems. Assuming the coolingof the intrusion is synchronous with a dicrease in local geothermal gradients, an emplacementdepth of about 8 km and the magma crystallization temperature of 800±50℃ are estimated. TheHuangmeijian intrusion experienced a rapid cooling process and uplifted after its emplacementand crystallization at 133 Ma B.P. with a cooling rate of 34.5℃/Ma and an uplifting rate of 0.35mm/a. The intrusion was rising until it rested at a depth of 3km at a temperature of 300±50℃about 14.Ma later. Then the intrusion was in slow cooling and uplifting with a cooling rate of4.4./Ma and an uplifting rate of 0.04.mm/a. U-Pb dating of pitchblende is done for the hydrothermal uranium deposit formed in thecontact zone of the Huangmeijian intrusion. The result shows that the mineralization age is closeto the closing time of the K-Ar system in biotite. The fluid inclusion thermometry indicates thatthe mineralization temperature is in agreement with the closure temperature of the biotite K-Arsystem. This suggests a close relationship between the slow cooling of the intrusion and thehydrothermal uranium mineralization process.

关键词： quartz syenite isotopic age oxygen isotope cooling history mineralization rate control

Mineral Composition and Metamorphic P-T Conditions of the Eclogitic Rocks in the Eastern Dabie Mountains and Their Genetic Implication

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Acta Geologica Sinica(English Edition) 1993年第4期67卷 387-402页

作者： Ge Ningjie, Li Shuguang, Peng Zhonghua and Liu Deliang department of earth and space sciences, {4. of science and technology of china, hefei, Anhui Jiang Minxi department of earth and space sciences University of Science and Technology of China Hefei Anhui

There are obvious differences in the mineral assemblage and metamorphic P-T conditions between the eclogites from the northern and southern parts of the eastern Dabie Mountains. Those from the northern part of the mountains are developed in Alpine peridotite and gneiss. They have a mineral assemblage of garnet+diopside with no quartz, and were formed at temperatures of 600℃-74.℃. Those from the southern part are developed in gneiss and marble. They consist of garnet+omphacite+less quartz and were metamorphosed at temperatures in the range of 650°-800℃. These differences suggest that the former may be formed during the metamorphism of the deep subducted oceanic crust, whereas the latter may be genetically related to the subduction of the continental crust in this area.

关键词： collisional orogen eclogitic rocks from the southern and northern parts of the Dabie Mountains T-P conditions

Pleonaste in Boxian meteorite

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Chinese science Bulletin 1998年第19期43卷 1656-1660页

作者： WANG Kuiren and HONG Ji’an department of earth and space sciences, {4. of science and technology of china Advanced Research Center for earth sciences and Astronomy, {4. of science and technology of china, Third World Academy of sciences department of earth and space sciences University of Science and Technology of China China Advanced Research Center for earth sciences and Astronomy University of Science and Technology of China Third World Academy of Sciences Hefei China

There are three kinds of occurrence of pleonaste, a rare meteoritic mineral, totally found in Boxian meteorite. They are as the following: (ⅰ) occurring in the inner circle of the chondrule edge, of which a circle texture is composed; (ⅱ) occurring in the state of inclusions, included in an olivine chondrule, with close paragenesis of wadsleyite; (ⅲ) occurring in the state of porphyry. The chondrule in the first occurrence belongs to CA chondrules. The chemical compositions of pleonaste are heterogeneity except for the atomic ratios of Fe/(Mg+Fe), which can be attributed to the following reasons: (ⅰ) they are congenetic minerals; (ⅱ) the heterogeneity of the compositions of the solar clouds in the early states; (ⅲ) the chondrites are the multiple-stage evolution; (ⅳ) the further proof of Boxian meteorite is an unequilibrium common chondrite.

关键词： rare pleonaste in meteorites found genesis.

The δ^(18)O variation of a stalagmite from Qixing Cave,Guizhou Province and indi-cated climate change during the Holocene

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Chinese science Bulletin 2001年第22期46卷 1904-1908页

作者： CAI Yanjun, ZHANG Meiliang, PENG Zicheng, LIN Yushi, AN Zhisheng, ZHANG Zhaofeng & CAO YunningState Key Laboratory of Loess and Quaternary Geology, Institute of earth Environment, Chinese Academy of sciences, Xi’an 710054. china Karst Dynamics Laboratory, Ministry of Land and Resources, Guilin 54.003, china {4. of earth and space science, university of science & technology of china, hefei 230023, china State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Karst Dynamics Laboratory Ministry of Land and Resources Guilin China department of earth and space science University of Science & Technology of China Hefei China

A stalagmite from Qixing Cave, Guizhou Province was dated with the TIMS U-series method and its oxygen isotope composition was analyzed. On the basis of the ages and the variations of the δ18O of the stalagmite, the climate change of the last 7.7 ka has been reconstructed in this area: 7.7-5.8 ka, summer monsoon maximum period; 5.8-3.8 ka summer monsoon weakening period; 3.8-0.15 ka, weakened summer monsoon and high amplitude climate fluctuations period. We put forward that the increasing trend of δ18O of the stalagmite reflected not only the weakening of the summer monsoon, which was caused by the decreasing of solar radiation in the Northern Hemisphere, but also the possibly decreasing contribution of the southwest monsoon to the rainfall of this area. These results are consistent with the output of the numerical climate-model modeling. The high amplitude fluctuation of the δ18O may imply the quick shift of the contributions of different moisture sources to the precipitation in this area.

关键词： stalagmite Holocene southwest monsoon.

Genesis of excess argon in phengite and significance of ^(4.)Ar-^(39)Ar age spectra for omphacite:A case study on UHP eclogite of South Dabie Terrain,china

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Chinese science Bulletin 2000年第15期45卷 1345-1351页

作者： WANG Songshan, GE Ningjie, SANG Haiqing & QIU Ji1. Institute of Geology and Geophysics, Chinese Academy of sciences, Beijing 100029, china 2. department of earth and {4. science, university of science and technology of china, hefei 23.026, china Correspondence should be addressed to Wang Songshan Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China department of earth and space science University of Science and Technology of China Hefei China

The Ar-Ar dating of phengite and omphacite in ultrahigh-pressure (UHP) eclogite of Bixiling and Hengchong in the South Dabie Terrain shows that the content range of excess argon is as high as (0.4.1.3)×10 8 mol· g 1. The genesis of the excess argon is discussed. The Ar-Ar age spectra of omphacite could not support the opinion that the UHP metamorphism occurred in Caledon epoch and pre-Caledon epoch.

关键词： South Dabie Terrain ultrahigh-pressure metamorphics phengite omphacite excess argon.

Petrogenesis and Geochemistry of Neogene Basalts in Eastern Anhui

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Acta Geologica Sinica(English Edition) 1995年第4期69卷 406-419页

作者： Zhi Xiachen, Chen Daogong and Yang Jindepartment of earth and space sciences, {4. of science andtechnology of china, hefei, Anhui Jiang M inxi department of earth and space sciences University of Science and Technology of China Hefei Anhui

The basalt terrain of the Neogene Huangguoshan and. Guiwu Formations of eastern Anhui on the east side of the Tancheng-Lujiang fault belt is one of a few Cenozoic basalt terrains in eastern china for which detailed geochemical study has not been conducted. This paper reports the abundances of major elements and more than 20 trace elements (including REE) of 22 samples and the Nd, Sr and Pb isotopic compositions of 11 samples from the eastern Anhui basalt terrain, thus more or less systematically revealing the geochemical characteristics of this continental basalt suite. The paper discusses the origin of the basalt suite and the character and process of its mantle source. The basalt suite was derived from a heterogeneous continental lithospheric mantle with end members characteristic of the EMI-type oceanic basalt mantle, which was affected by mantle metasomatism (or enrichment of trace elements) and was characterized by a multi-stage evolution under open conditions.

关键词： continental alkali basalt EM I-type mantle end-member eastern Anhui

Paleotemperature changes over the past 3000 years in eastern Beijing, china: A reconstraction based on Mg/Sr records in a stalagmite

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Chinese science Bulletin 2003年第4期48卷 395-400页

作者： MA Zhibang1, LI Hongchun2, XIA Ming1, KU Tehlung2, PENG Zicheng3, CHEN Yushu4.& ZHANG Zhaofeng3 1. Institute of Geology and Geophysics, Chinese Academy of sciences, Beijing 100029, china 2. department of earth sciences, university of Southern California, Los Angeles, CA90089-074., USA 3. department of earth and space science, university of science and technology of china,{14., china 4. Beijing Foshan Tourist Service Centre, Beijing 101201, china Institute of Geology and Geophysics. Chinese Academy of sciences Beijing 100029 China

The Mg/Sr ratio in a stalagmite, which is di-rectly proportional to DMg/Ca, the solid-liquid distribution coefficient of Mg, is proposed as a geochemical thermometer to estimate paleotemperature changes. The paleotempera-ture change in eastern Beijing over the past 3000 years has been reconstructed by using this thermometer in the stalag-mite ZFFS-1 from Jingdong Cave. The records can be di-vided into two periods: 3000—2000 aBP, cool and wet, the air temperature averaging 9.8℃; and 2000 aBP—present, hot and dry, the air temperature being 1℃ higher than the mean value (11.7℃) of the past 3000 years. During 500—200 aBP, the air temperature was about 1.2℃ lower than that of the present, corresponding to the Little Ice Age in Europe. Like d 18O and d 13C, Mg/Sr (or DMg/Ca) reflects an obviously warming trend of the past 200 years. These results are sup-ported by historic records.

关键词：北京京东溶洞石笋 Mg/Sr记录古气温测年 3000年