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Pb isotope geochemistry of lead, zinc, gold and silver deposit clustered region, Liaodong rift zone,northeastern china

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Science china earth {2. 2005年第4期48卷 467-476页

作者： CHEN Jiangfeng1, YU Gang1, XUE Chunji2. QIAN Hui1, HE Jianfeng1, XING Zhi1 & ZHANG Xun1 1. School of earth and Space sciences, University of Science and Technology of{2., Hefei 2.002.,{2. 2. department of Geology, Chang’an University, Xi’an 710054,{2. 1. School of earth and Space sciences University of Science and Technology of China 230026 Hefei China 2. department of Geology Chang’an University 710054 Xi’an China

Pb isotopic analyses were reported for sulfide and hydrothermal carbonate minerals and marble of the Xiquegou lead-zinc, the Zhenzigou zinc-lead and the Gaojiapuzi silver deposits from the Qingchengzi ore field and the Beiwagou zinc-lead deposit in the west, Proterozoic Liaodong rift zone. Pb isotopic ratios of the marble from the Qingchengzi ore field range from 18.2. to 30.63 for 2.6 Pb/2.4Pb, 15.59 to 17.05 for2.7Pb/2.4Pb and 37.43 to 38.63 for 2.8Pb/2.4Pb. The marble gives a Pb-Pb isochron age of 182.±92.Ma, which is interpreted as the age of the metamorphism of the marble. Ore Pb, including Pb of sulfide and hydrothermal car- bonate minerals, from the Qingchengzi ore field shows limited variation with 2.6 Pb/2.4Pb=17.66- 17.96, 2.7 Pb/2.4Pb=15.60-15.74 and 2.8Pb/2.4Pb=37.94-38.60. In contrast, ore Pb from the Beiwagou deposit gives different Pb isotopic ratios with 2.6Pb/2.4Pb=15.68-15.81, 2.7 Pb/2.4Pb= 15.34-15.45 and 2.8Pb/2.4Pb=35.30-35.68. Pb of all deposits from the Liaodong rift zone is derived from the upper crust. Ore Pb of the Qingchengzi deposits is derived from a young upper crust. The model Th/U ratios of 4.40 to 4.74 for ore Pb are significantly different from that of 1.7 to 4.4 given by the marble of the Qingchengzi ore field, suggesting that marble is not the source of the ore Pb. Ore Pb of the Beiwagou deposit is extracted from its source and the deposit is formed at the Paleoproterozoic era. Different Pb isotopic ratios of the Qingchengzi ore field and the Beiwagou deposit are due to different ages of the deposits and suggest that the two types of deposits are derived from different sources and are possibly formed by different ore-forming processes.

关键词： Pb isotopes, source(s) of the ore-forming materials, origin of ore deposits, Liaodong rift zone.

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Geochemical constraints from hydrothermal fluid inclusions of altered deformation zone type Au(Ag)deposits in Yunkai area, South china

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Chinese Science Bulletin 1999年第S2期44卷 230-232页

作者： WANG Zuwei~1, ZHANG Haihua~2. YAO Dongliang~2.and ZHOU Yongzhang~3 1. department of Geography, Tianjin Normal University, Tianjin 300071, china 2. Guangzhou Institute of Geochemistry, Chinese Academy of {2., Guangzhou 510640, china 3. department of earth {2., Zhongshan University, Guangzhou 5102.5, china eeszhou@*** department of Geography Tianjin Normal University Tianjin 300071 China Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China department of earth {2. Zhongshan University Guangzhou 510275 China

THE altered deformation zone type Au (Ag) deposits share an important part from the precious metallicore deposits in the Yunkai area, South china. Their formation is a history of poly-stage evolution. Pre- liminary source strata, Calidoniam metamorphism, Indosinian-Yanshanian ductile shear deformation andassociated hydrotheraml alteration all play certain roles in the history. This note discusses the geochemical conditional of the hydrothermal fluids during mineralization. Two representative ore deposits, the Pangxidong Ag(Au) deposit and Hetai Au deposits are selectedfor this study. They are hosted in altered ductile shear zones. Wall-rock hydrothermal alteration is bothspatially and temporally associated with the development of the ductile shear system. Silicification occurred throughout the whole alteration process. There are three groups of quartz: thepredeformational quartz, the early stage hydrothermal quartz, and the late stage hydrothermal quartz asso-

关键词： precious metallic deposit fluid inclusions mineralizing fluid South china.

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The Sedimentologic-Geotectonic Evolution in the Jiangsu-Zhejiang-Anhui Region

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Acta Geologica Sinica(English Edition) 1989年第2期63卷 127-137页

作者： Xia Bangdong and Lu Hongbo department of earth {2., nanjing University, nanjing, Jiangsu Liu Linqun department of earth {2. Nanjing University Nanjing Jiangsu

The Yangtze plate, extending from east to west in southern china, was formed about 800 Ma ago. Since the Sinian, two aulacogens trending east-northeast and connected at the east ends, have been initiated in the Jiangsu-Zhejiang-Anhui region on the east margin of the plate with a sedimentary sequence up to 10,000 m in thickness. At a later stage of sedimentologic evolution, flysch and molasse were produced. The flyseh was accumulated in the Late Ordovician, when the two aulacogens became bays that opened to the east; the elastic materials were derived from the Yangtze oldland on the northern and southern sides of the basins. The molasse was accumulated from the terminal Late Ordovician to the Middle Ordovician; the clastie materials came from an uplifted orogenic belt in the east. This indicates that a major change in the tectonic pattern of the basins has taken place.

关键词： Ordovician sedimentary accumulated Jiangsu Anhui northeast tectonic Yangtze sandstone margin

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Thermal-rheological structure of lithosphere beneath the northern flank of Tarim Basin, western china: Implications for geodynamics

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Science china earth {2. 2004年第7期47卷 659-672页

作者： LIU Shaowen1, WANG Liangshu1, LI Cheng1, LI Hua1, HAN Yongbing1, JIA Chengzao2.& WEI Guoqi2.1.department of earth {2., nanjing University,nanjing 2.0093, china 2.Chinese Petroleum Exploration and Development Institution,Beijing 100083,china 1. department of earth {2. Nanjing University 210093 Nanjing China 2. Chinese Petroleum Exploration Development Institution 100083 Beijing China

Based on the data of geo-temperature and thermophysical parameters of rocks in the Kuqa Depression and the Tabei Uplift, northern flank of the Tarim Basin, in terms of the analytical solution of 1-D heat transfer equation, the thermal structure of the lithosphere under this region is determined. Our results show that the average surface heat flow of the northern flank of the Tarim Basin is 45 mW/m2. and the mantle heat flow is between 2. and 2. mW/m2. the temperature at crust-mantle boundary (Moho) ranges from 514°C to 603°C and the thermal lithosphere where the heat conduction dominates is 138–182.km thick. Furthermore, in combination with the P wave velocity structure resulting from the deep seismic sounding profile across this region and rheological modeling, we have studied the local composition of the lithosphere and its rheological profile, as well as the strength distribution. We find that the rheological stratification of the lithosphere in this region is apparent. The lowermost of the lower crust is ductile; however, the uppermost of the mantle and the upper and middle parts of the crust are both brittle layers, which is typically the so-called sandwich-like structure. Lithospheric strength is also characterized by the lateral variation, and the uplift region is stronger than the depression region. The lithospheric strength of the northern flank of the Tarim Basin decreases gradually from south to north; the Kuqa Depression has the lowest strength and the south of the Tabei Uplift is strongest. The total lithospheric strength of this region is4.77×1012.5.03×1013 N/m under extension, and 6.5×1012.9.4×1013 N/m under compression. The lithospheric brittleductile transition depth is between 2. km and 33 km. In conclusion, the lithosphere of the northern flank of the Tarim Basin is relatively cold with higher strength, so it behaves rigidly and deforms as a whole, which is also supported by the seismic activity in this region. This rigidity of the Tarim lithosphe

关键词： thermal-rheological structure of lithosphere, rheological stratification, geodynamics, Tarim Basin.

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Discovery of Corallina fossil from the Middle Cambrian of Taijiang County, Guizhou Province, china

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Chinese Science Bulletin 2000年第6期45卷 544-547页

作者： YANG Ruidong & ZHAO Yuanlong department of earth {2., nanjing University, nanjing 2.0093, china department of Resources, Guizhou University of Technoiogy, Guiyang 550002. china department of earth {2. Nanjing University Nanjing China department of Resources Guizhou University of Technology Guiyang China

Abundant and well-preserved macroalgae fossils have been discovered in silty mudstones and shales from the Middle Cambrian of Taijiang County, Guizhou Province, china. Corallina Paraamphiroa siniansis gen. et sp. nov. in the Kaili Fm., is the earliest Corallina fossil, which usually coexists with other carbonaceous macroalgae fossils on the bedding planes of mudstone and shale and is different from the calcareous and phosphatized Precambrian-Cambrian thallus discovered in the Lower Cambrian of Siberia and the Doushantou phosphate rocks of Weng’an County, Guizhou Province, china. The discovery of calcified thallus in the Kaili Fm. bears great importance on the study of phylogeny and evolution of early calcareous macroalgae.

关键词： Corallina Middle Cambrian Guizhou Province china.

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Multifractal modelling and spectrum analysis: Methods and applications to gamma ray spectrometer data from southwestern Nova Scotia, Canada

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Science china earth {2. 2006年第3期49卷 283-294页

作者： CHENG Qiuming1,2.1. State Key Lab of Geological Processes and Mineral Resources, china University of Geosciences, Wuhan 430074, china 2. department of earth and Space Science and Engineering, department of Geography, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada 1. State Key Lab of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China 2. department of earth and Space Science and Engineering Department of Geography York University 4700 Keele Street Toronto Ontario M3J 1P3 Canada

Multifractal spectrum, autocorrelation/semivariogram and power spectrum are three dif- ferent functions characterizing a field or measure from different aspects. These functions are interre- lated in such that the autocorrelation/semivariogram and power spectrum are related to the low order statistical moments (0 to 2.nd) which may determine the local multifractality (τ ″(1)) of a multifractal measure. A better understanding of the interrelationships among these three functions is important because, on one hand, the multifractal modelling characterizes a multifractal measure in a more de- tailed manner since it involves moments of all orders. On the other hand, the commonly used semivariogram and power spectrum functions can be used as alternatives to study the dominant mul- tifractal properties around the mean measure. Moreover, semivariogram and power-spectrum func- tions provide spatial and spectral information, which is highly valued in geological applications. A new fractal relation found between area and power-spectrum will be useful for investigation of new meth- ods of spatial-spectral analysis for pattern recognition, anomaly separation, classification, etc. These results have been demonstrated with the case study of modelling gamma ray spectrometer data from the mineral district, southwestern Nova Scotia, Canada. The results have shown that the values of uranium (U), thorium (Th) and potassium (K) may possess monofractal properties whereas the ratios of these values show high multifractality. The values of the ratios U/K and U/Th show relatively large variances and may provide more information for distinguishing the distinct phases of the granites, country rocks as well as possible gold mineralization-associated regional hydrothermal alteration zones. In addition, the power spectra for U, Th, K, U/Th and U/K consistently show two distinct power-law relationships for two ranges of wave number 12.ω ≤160 km and 0≤ω ≤12.km. These properties might provide usefu

关键词： gamma ray spectrometer data, gold mineralization, alteration zones, multifractal modelling, spectral analysis, GIS.

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Sm-Nd isotopic ages of Tiqiushan eclogites in Xinyi region and its geological significance

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Chinese Science Bulletin 1999年第S2期44卷 144-146页

作者： WANG Yinxi~(1,2., YANG Jiedong~(1,2., TAO Xiancong~(1,2., GE Ningjie~4, CHEN Peirong~3, FAN Chunfang~3 and LI Jianhua~5 1. Center of Modern Analysis, nanjing University, nanjing 2.0093,{2. 2. State Key Laboratory for Research of Mineral Deposits, nanjing University, nanjing 2.0093,{2. 3. department of earth Science, nanjing University, nanjing 2.0093,{2. 4. department of earth and Space sciences, University of Science and Technology of Chian, Hefei 2.002.,{2. 5. No.5 Geological Party of Jiangsu Province, Xuzhou 2.1005,{2. Center of Modern Analysis Nanjing University Nanjing 210093 China State Key Laboratory for Research of Mineral Deposits Nanjing University Nanjing 210093 China department of earth and Space {2. University of Science and Technology of Chian Hefei 230026 China department of earth Science Nanjing University Nanjing 210093 China No. 5 Geological Party of Jiangsu Province Xuzhou 221005 China

GEOLOGICAL scientists have paid much attention to the suture zones formed by collision between the Sino-Korean and Yangtze blocks because of the discovery of the ultrahigh pressue metamorphic (UHPM) rocksfrom northern Jiangsu Province (Su), southern Shandong Province (Lu) and the Dabie *** the age of 2.0-2.0 Ma is probably the best estimation for UHPM metamorphism in the DabieMountains, the primary intrusive and metamorphic ages of the complex from northern Jiangsu Provincehave not been determined before. Using the Sm-Nd isotopic dating method, our study is aimed at datingthe UHPM metanorphic event of northern Jiangsu Province and researching a probable relation between theUHPM rocks from the Dabie Mountains and the UHPM rocks from northern Jiangsu Province.

关键词： northern Jiangsu eclogite rocks Sm-Nd isotopic ages.

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Metallogenic geochemistry of Sb-mineralization in southern margin of North china platform

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Chinese Science Bulletin 1999年第S2期44卷 17-18页

作者： YANG Xiaoyong~1, YANG Xueming~1, ZHANG Jianjun~2. CAO Gaoshe~2.and ZHANG Zhengwei~2.1. department of earth and Space {2., University of Science and Technlogy of china, Hefei 2.002., china 2. Institute of Geology, Henan Bureau of Geology and Mineral Resources, Zhengzhou 450053, china department of earth and Space {2. University of Science and Technology of China Hefei 230026 China Institute of Geology Henan Bureau of Geology and Mineral Resources Zhengzhou 450053 China

1 Geological setting THE Sb mineralization zone in the south margin of North china platform is located in the transitional edgeof North china plate and Yangtze plate, belonging to Qinling fold system, whose tectonic line is inNWW-SEE direction regionally. Because of the huge compression caused by the collision of the twoplates, the rocks undergone strong deformation and metamorphism have very complicated structures. Theregional deep fault-Shuanghuaishu fault-controls Sb-mineralization zone belt, and all the Sb-oredeposits or mineralized spots appear alone at the very southern margin of the fault. The lithostragraphirunits in the mineralized zone are relatively simple, mainly composed of Jiebei Group （Pt2./sub>J2./sup>） of QinglingFormation （with middle-high metamorphsim） and the upper Triassic system （with little metamorphism）.

关键词： Sb-mineralization metallognic geochemistry North china plateform.

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Occurrence of mixed-layer illite/smectite at temperature of 2.5℃ in an active hydrothermal system and its significance

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Chinese Science Bulletin 1997年第4期42卷 318-321页

作者： Jl Junfeng, P. R. L. Browne and LIU Yingjun1. department of earth {2., nanjing University, nanjing 2.0093, china 2.Geothermal Institute and Geology department, University of Auckland, New Zealand department of earth {2. Nanjing University Nanjing China Geothermal Institute and Geology department University of Auckland New Zealand

THE progressive transformation of smectite into illite via mixed-layer illite/smectite (I/S) phases occurs during hydrothermal alteration, burial diagenesis and regional metamorphism. The proportion of illite or smectite (also indicated by their expandability) and ordering of I/S, interpreted by X-ray powder diffraction (XRD) profiles, have long been used as geothermometers in sedimentary basins. It is found that R=1 ordering mixed-layer I/S still exists

关键词： mixed-layer illite/smectite geothermometer hydrothermal system.

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A possible Younger Dryas-type event during Asian monsoonal Termination 3

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Science china earth {2. 2006年第9期49卷 982-990页

作者： CHEN Shitao1, WANG Yongjin1, KONG Xinggong1, LIU Dianbing1, CHENG Hai2.& R.L. Edwards2.1. College of Geography Science, nanjing Normal University, Jiangsu Key Laboratory of Environmental Change and Ecological Construction, nanjing 2.0097,{2. 2. department of Geology and Geophysics, University of Minnesota, Minneapolis MN55455, USA 1. College of Geography Science Nanjing Normal University Jiangsu Key Laboratory of Environmental Change and Ecological Construction Nanjing 210097 China 2. department of Geology and Geophysics University of Minnesota Minneapolis MN 55455 USA

Seven U-Th dates, 560 δ 18O data and microscopic sequences were measured for sta- lagmites from two high-altitude caves in Shennongjia area, Hubei Province. Variations of the de- cadal-resolution stalagmite δ 18O record from Swan Cave (1600 m elevation) reflect large spatial changes in circulation strength and precipitation of Asian monsoon. The evidence comes from a great similarity among the stalagmite δ 18O records from nanjing, Jiangsu Province; Libo, Guizhou Province and here studied area during the last deglaciation, including a part interval of Younger-Dryas event and Bolling-Allerod. A 30-year-resolution stalagmite δ 18O record from Yongxing Cave (1400 m eleva- tion), 70 km away from Swan Cave, reveals a rapid transition of Asian monsoon climate during Ter- mination 3 at about 2.5±5 kaBP. Based on 3 U-Th dates and about 5000 continuous annual bands, a millennial dry episode has been observed during Asian monsoonal Termination 3 from the Yongxing δ 18O profile. With respect to its structure, duration and transition, the dry reversal, as indicated by our stalagmite δ 18O record, generally agrees with the pattern of the YD event well-expressed in the Chi- nese stalagmite δ 18O records. This YD-type event is characterized by a large decrease in δ 18O value as much as 2.30‰, more than half of the δ 18O excursion between glacial/interglacial periods, and lasts 1371±59 a determined by the annual counting chronology. After this event, the monsoon climate shifted abruptly into the interglacial period within 74±4 a. Our data corroborate the view that the re- peated occurrence of YD-type event was not an “accident”, possibly resulted from the coupling of ice-sheet and oceanic/atmospheric circulations.

关键词： stalagmite, Termination 3, Asian monsoon, YD-type event, Shennongjia, Hubei Province.

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