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Deep Tectonic Processes and Superaccumulation of Metals Related to Granitoids in the Nanling MetaUogenic Province,China

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Acta Geologica Sinica(English Edition) 1999年第2期73卷 181-192页

作者： PEI Rongfu, WANG Ping’an, and PENG Cong institute of Mineral Deposits, cags, 2. Baiwanzhuang Rd., Beijing 10003. institute of geomechanics, cags, Beijing 100081 cags Inst Mineral Depositis Beijing 100037 Peoples R China cags Inst Geomech Beijing 100081 Peoples R China

The Nanling region is an important nonferrous and rare metal metallogenic province in South China, in which most of the deposits are related to granitoids in genesis. It covers southern Hunan, southern Jiangxi, Guangxi, Guangdong and Fujian provinces, with a total area of about 550,000 km2. This metallogenic province is well known in the world for its rich tungsten and tin resources. In the past 40-odd years, a vast amount of mineral exploration activities and studies of the geology of mineral deposits have been carried out and great achievements obtained in the province. This paper is focused on a discussion about the deep tectonic processes in the orogenic belt during the Mesozoic and their contribution to the superaccumulation of metals. Tectonically, this metallogenic province is composed of three units: (1) the marginal continental orogenic belt in the Southeastern Coast fold system in the Yanshanian; (2. the intercontinental orogenic belt in the collision suture belt between the Yangtze and Cathay-sian plates mainly in the Caledonian; and (3. the intracontinental orogenic belt induced by subduction of the ocean crust and delimination of the mantle lithosphere in the Yanshanian. It is suggested that superaccumulation of metals in this metallogenic province was caused by the existence of mantle rooted tectonics at the depth based on comprehensive studies of geophysical information of seismic, geothermal and magnetotelluric surveys in Nanling and its adjacent areas. The Xihuashan wolframite quartz vein deposit, the Shizhuyuan W, Sn, Mo, Bi greisen-skarn deposit and the Dachang tin-polymetallic deposit are three typical examples of the deep tectonic processes. However, this kind of deep tectonic processes only act as the 'engine' of the superaccumulation of metals, which means that they should have to correspond with the super-crust ore-controlling pattern of 'lines-rows-clusters' (L-R-C). This recog-nization is expected to play an important role in assessment of

关键词： deep tectonic process superaccumulation of metals Nanling China

Dynamic Analysis of Deformational Structures of the Xianniishan Fault Zone in the Three Gorges of the Yangtze River

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Acta Geologica Sinica(English Edition) 1999年第2期73卷 163-172页

作者： WU Shuren institute of geomechanics,{2., Beijing {3.and WU Ganguo China University of Geosciences, Beijing 100083.Liu Xinzhu

Field investigation and laboratory work reveal that inhomogeneity of the deformation of the Xiannushan fault is mainly characterized by lateral zonation, longitudinal segmentation and downward stratification. Based on these results, a 3.D deformational structure model of the fault was established and its geometrical and kinematic characteristics in two main deformational stages i.e. the main Yanshanian and Himalayan were discussed. The directions of principal and the differential stresses in these two stages were determined by using conjugate joints, striations of fault planes and microstructures of the fault zone. The direction of σI is N-S in direction with differential stresses of 150-2.0 MPa in the Yanshanian, and N70E with a differential stress ranging from 80-12. MPa in the Himalayan.

关键词： three gorges of the Yangtze River Xiannushan fault fault deformation structure differential stress

APPLICATION OF SOME MECHANICAL CONCEPTS TO STRUCTURAL GEOLOGY

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Geotectonica et Metallogenia 2003年第1期27卷 120-129页

作者： WU Hongling and WANG Wei (institute of geomechanics, {2., Beijing {3., China) institute of geomechanics CAGS Beoing 100081 China

This paper discusses some mechanical concepts that have been largely applied to structural geology and tectonics, and addresses the problems and misunderstandings in use of these mechanical terms. The purpose is to stimulate the interests for structural geologists in using the mechanical principles and methods correctly to solve the geodynamic problems.

关键词： dynamics kinematics stress strain elasticity plasticity viscosity.

EFFECTS OF TECTONIC FORCE ON HYDROSTATIC PRESSURE DURING PETROGENESIS AND METALLOGENESIS

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Geotectonica et Metallogenia 1995年第Z1期19卷 39-47页

作者： Lu Guxian Yin Jicai(institute of geomechanics, {2., Beijing, {3., China)

Research on hydrostatic pressure in the crust has been previously conducted from the viewpoint that the hydrostatic pressure is equal to gravity,considering the hydrostatic preessure in the geochemical process of petrogenesis and metallogenesis is mainly derived from the gravity of overlying rocks. This paper suggests that the stress state of any point in the crust is caused by both gravity and tectonic *** author puts forward a viewpoint that the hydrostatic pressure is a combination or superposition of two isotropic stresses, i. e. tectonic force and gravity, in the stress field. The results obtained by a finite-element simulation indicate that the. additional hydrostatic pressure borne by rocks decreases gradually frotn the compression zone (K), the shear zone to the tensile sone (K) and the difference of the tectonic additional hydrostatic pressure between these deformed zones tends to increase, following the increase in absoIute vaIue and/or difference of external forces in different *** study tries to explain the effects of tectonic force on hydrostatic pressure during petrogenesis and metallogenesis,which will lay the foundation for research on tectonic physico-chemistry.

关键词： tectonic deformed zone tectonic additional hydrostatic pressure tectonic physico-chemistry

GRANITOIDS,VOLCANIC ROCKS AND CHERTS FROM NORTH ALTYN TAGH,NW CHINA: IMPLICATION FOR THE TECTONIC ENVIRONMENT DISCRIMINATION

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地学前缘 2000年第S1期7卷 249-250页

作者： Chen Xuanhua\+1,Wang Xiaofeng\+1,Chen Zhengle\+1,George Gehrels\+2.Yin An\+3.WT5,5”BX](1.institute of geomechanics,{2.,Beijing 100081,China 2.Department of Geosciences, University of Arizona,Tucson,AZ 8572.,USA 3.Department of Earth and Space Science

Granitoids,volcanic rocks and cherts,mainly of early Paleozoic,in northern Altyn Tagh(Fig.1) are analyzed here for the purpose of the determination of the tectonic environments and their development since Early Paleozoic.(1) Granitoids\ The collection of 12. main\|element petrochemical data from North Altyn Tagh area shows that most of the granitoids here are granites and granodiorites of calc\|alkaline *** consist mainly of metaluminous and peraluminous in Shand’s index,and only one of them,which belongs to Mesozoic,is *** of the granitoids plot in the IAG+CAG+CCG fields in the Maniar and Piccoli’s diagrams (1989) for tectonic discrimination of *** (Island arc granitoids)and CAG (Continental arc granitoids) can be distinguished for Early and Late Paleozoic granitoids,and maybe some CCG (Continental collision granitoids) for Early *** of Mesozoic and Cenozoic inherited the characteristics of those of *** active plate margin (pre\|plate collision)and Anatectic magmatism(syn\|orogenic,S\|type granites)are distinguished (Fig.2.for Paleozoic granitoids using de la Roche R 1\| R 2.multicationic diagram (Batchelor and Bowden,1985).Mesozoic and Cenozoic granitoids inherited the characteristics of Anatectic magmatism (syn\|orogenic)of these early ones,and post\|orogenic(A\|type)granites occurred in *** mechanism for magma formation is mainly partial melting.

关键词： granitoids volcanic rocks cherts tectonic environ ment Altyn Tagh

Study on Mineralization Age of Xiaoban Gold Deposit, Fujian Province

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Journal of China University of Geosciences 2002年第3期13卷 225-233页

作者： Chen Bailin institute of geomechanics, {2., Beijing {3. Wu Ganguo Faculty of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083.Zhang Da institute of geomechanics, {2., Beijing {3. Huang Rensheng West Fujian Geological Party of FBGMRE, Sanming 3.5000 Wu Jianshe Fujian Bureau of Geological and Mineral Resources Exploration, Fuzhou 3.0003 institute of geomechanics CAGS Beijing 100081 Faculty of Earth Sciences and Mineral Resources China University of Geosciences Beijing 100083 West Fujian Geological Party of FBGMRE Sanming 365000 Fujian Bureau of Geological and Mineral Resources Exploration Fuzhou 350003

The Xiaoban gold deposit is a large-size deposit recently found in middlearea of Fujian Province. It belongs to magmatic hydrothermal type occurred in Mayuan Groupmetamorphic rocks of Middle Proterozoic and is controlled by low angle fault (detachment)structures. The contents of Au in Mayuan Group metamorphic rocks, Caledonian-Indosinian deformedgranite and early Yanshanian granite are higher with Au enrichment coefficient of 2. 06-5.68, 5.11and 6.67 than those in other geological bodies. And the higher enrichment coefficients (>2. of Ag,S, Sn and Te are similar to those of gold ore. Meanwhile, the distribution of Au in Mayuan Groupmetamorphic rocks and early Yanshanian granite with a low D-value (0.58 and 0.67) is favorable togold mineralization. REE characteristics of gold ore, ratios of (LREE/HREE), (La/Sm)_n, (Yb/Lu)_n,(La/Tb)_n and (Sm/Nd)_n are similar to Mayuan Group metamorphic rocks, only non or little normal Euabnormal of ore is dissimilar to metamorphic rocks. The δ(^(3.)S) of the gold ore, with a highhomogenization, is (-4.7X10^(-3. - (-2.7X 10^(-3.). The study of inclusion indicates 180-2.9℃ ofmineralization temperature, 3. 69 %-11. 81 % of salinities and 0. 869-0.991 g/cm^3.of densities ofmineralization fluid. Based on hydrogen and oxygen isotope (δ(^(18)O) = 11. 0 X 10^(-3. -11.7 X10^(-3., δ(D) = (-48 X 10^(-3.) - (-62.X 10^(-3.)) and initial w(^(87)Sr)/w(^(86)Sr) =0. 715,combining to the analysis of geological history, regional metamorphism and magamtic activity, theauthors confirm that the source for the ore fluid was mainly from magmatic, partly from metamorphicwater, and with a little influence of meteoric water. Isotopic dating made on Rb-Sr isochron age of182.Ma, by using alteration minerals of gold-ores from the deposit, indicates that themineralization occurs in early Yanshanian epoch. This is close to the age of 187 Ma of the Anchunmagmatite with a similar alteration and gold mineralization to the Xiaoban gold deposit. The age ofearly Yanshan

关键词： mineralization age early yanshanian epoch xiaoban gold deposit fujian

Post-Mesozoic Transformation of Tectonic Domain in Southeastern China and Its Geodynamic Mechanism

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Journal of Earth Science 2000年第3期19卷 94-98页

作者： Wu Ganguo Zhang Da Faculty of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083. China Chen Bailin institute of geomechanics, {2., Beijing {3., China Wu Jianshe institute of Geological Survey of Fujian Pr

Since the Mesozoic and Cenozoic, a transformation from a Tethyan Himalayan tectonic domain into a circum Pacific tectonic domain from Indosinian to Yanshanian is indicated in this paper, resulting in conspicuous changes in geophysics, tectono magmatic distribution, lithofacies and paleo geography, tectonic system in southeastern China. Tectonic analysis shows that the tectonic framework resulted from the compounding, transforming and superimposing of the two tectonic domains. The geodynamic mechanism of the transformation is mainly shown as the transverse and longitudinal heterogeneity of lithosphere, and the exchange between the crust and the mantle.

关键词： transformation of tectonic domain geodynamic mechanism southwestern Fujian Province southeastern China.

A BRIEF INTRODUCTION OF THE QUATERNARY GEOLOGY AND PALEOANTHROPOLOGY OF YUANMOU,YUNNAN,CHINA

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A BRIEF INTRODUCTION OF THE QUATERNARY GEOLOGY AND PALEOANTH...

Analysis on the Dynamical Process of Donghekou Rockslide-Debris Flow Triggered by 5.12.Wenchuan Earthquake

作者： Qian Fang Jiang Fuchu (institute of geomechanics,{2.)

＜正＞The project on Quaternary geology and palaeoanthropology of Yuanmou,Yunnan, Chian subsidized by the Funds of State Natural Science,the Funds of Geological Trade and other,from 1986 to 1990,the institute of geomechanics organized and concerned with the Beijing Natural History Museum,institute of Vertebrate Paleonotology and Paleoanthro- pology,Academia Sinica and other units to jointly carried out comprehensive research and

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Journal of Mountain Science 2011年第2期8卷 140-148页

作者： SUN Ping ZHANG Yongshuang SHI Jusong CHEN Liwei Key Laboratory of Neotectonic Movement & Geohazard Ministry of Land and Resources Beijing China institute of geomechanics Chinese Academy of Geological Sciences Beijing China China Nuclear Power Engineering Corporation Ltd. Beijing China

Among the geo-hazards caused by the great Wenchuan Earthquake, the rapid and long runout rockslide-debris flow is of primary concern due to the large volume of displaced material and the resultant catastrophic impacts to the landscape and socioeconomic structure. In order to analyze the dynamical process of this kind of geo-hazard, the Donghekou rockslide-debris flow is given as an example in this paper. This event, which killed 780 people, initiated at an elevation of 13.0 m with a total long run-out distance of more than 2.00 m. The slide mass is mainly composed of dolomite limestone and siliceous limestone of Sinian system, together with carbon slate and phyllite of Cambrian. During the processes from slide initiation to the final cessation of slide movement, five dynamic stages took place, here identified as the initiation stage, the acceleration of movement stage, the air-blast effect stage, the impact and redirection stage and the long runout slidematerial accumulation stage. Field investigations indicate that due to the effects of the earthquake, the dynamics of the Donghekou rockslide-debris flow are apparently controlled by geologic and tectonic conditions, the local geomorphological aspects of the terrain, and the microstructural and macroscopic mechanical properties of rocks which compose the slide mass. These three main factors which dictate the Donghekou rockslide-debris flow dynamics are discussed in detail in this paper, and significant results of field investigations and tests of materials are presented. The above dynamical processes are analyzed in this paper, and some useful conclusions have been gained.

关键词： Dynamical process Donghekou Rockslide-debris flow Wenchuan earthquake