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Ages and Compositions of the Precambrian High-grade Basement of the Qilian Terrane and Its Adjacent Areas

Acta Geologica Sinica(English Edition) 2001年第4期75卷 375-384页

作者： WAN Yusheng, XU Zhiqin, YANG Jingsui and ZHANG Jianxin institute of Geology, chinese academy of geological sciences, beijing 10003. institute of Geology Chinese Academy of Geological Sciences Beijing 100037 [?]2Wan Yusheng Born in 1958 graduated from china University of Geosciences in 1981 received the Ph.D. degree in 1993 now senior geologist at the institute of Geology Chinese Academy of Geological Sciences engaged in the study of geochemistry. Tel: 010–683.8411 e-mail: wanysh@***

Based on geological, chronological, geochemical and Nd isotopic studies of the high-grade basement of the Qilian terrane, the authors have drawn the following main conclusions: (1) the high-grade basement of the Qilian terrane consists mainly of meta-argillo-arenaceous rocks and granites and its bulk part was formed in the period of 0.8–1.0 Ga (the Jinningian period); (2) most of the meta-argillo-arenaceous rocks and granitic rocks have strong negative Eu and Ba anomalies (Eu/Eu*= 0.47–0.71 and Ba/Ba*=0.16–0.64), with fDM and ENd (1.0 Ga) ranging from 1.87 to 2.26 Ga and from ?8.54 to ?4.06 respectively, showing relatively high maturity; and (3. the Jinningian granitic rocks are a typical product of continent-continent collision, being probably related to the formation of the supercontinent Rodinia. These studies, combined with the study of high-grade basement rocks near the Qilian terrane, suggest that before the Jinningian period, the Qilian-Qaidam northern-margin terrane and Dunhuang-Alxa terrane were separated from each other, belonging to different plate systems of the North china craton and Yangtze platform respectively. The Qilian orogenic belt was the same as or similar to the Qiling orogenic belt in terms of the geological evolution history at least before the Jinningian period.

关键词： Qilian terrane chronology Nd isotope geochemistry Precambrian basement

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Chengdeite-A New Mineral of Ordered Natural Iron-iridium Alloy

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Acta Geologica Sinica(English Edition) 1996年第1期70卷 27-32,108页

作者： Yu Zuxiang institute of Geology, chinese academy of geological sciences, beijing

Chengdeite occurs in chromite orebodies in dunite as well as in placers in their neighbourhood. The mineral occurs as granular aggregates in association with inaglyite and in some cases occurs as graphic intergrowths with native iridium. It is opaque with a metallic lustre, colour steel-black, streak black,HM = 5.2, VHN50=452 kg/mm2, cleavage not observed, fracture not observed, strongly magnetic. Its reflection colour is bright white with a yellowish tint. It has no internal reflection, bireflectance or pleochrism, and shows *** chemical analyses were carried out by means of the electron microprobe. The mean percentages of the data obtained in the 13.analyses ares S 0.001, Fe 7.9, Ni 0.03. Co 0.03. Cu 0.83. As 0.02, Rh 0.19, Pd 0.00, Os 0.06, Ir 88.5, Ft 2.2 and Pb 0.00. The simplified formula is Ir3.e, which requires Ir 91.17 and Fe 8.83. the total being 100.00 (% ).Five strongest lines of X-ray powder diffraction (hkl, d, I)are: 111, 2.18 (80);200, 1.89 (60); 220, 1.3. (70);3.1, 1.142 (100);222,1.094 (80).Through indexing of the X-ray powder diffraction data, the mineral has been determined to be cubic with Pm 3., a = 0.3.92(5)nm, V = 0.05453.m and Z = 1.

关键词： new mineral chengdeitc chromite ore

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A new method for spatio-temporal prediction of rainfall-induced landslide

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Science china Earth sciences 2006年第4期49卷 421-430页

作者： DING Jixin1,2, YANG Zhifa2, SHANG Yanjun2, ZHOU Shenghua1 & YIN Juntao3.1. china Non-ferrous Metals resource geological Survey, {3. 100012, china 2. institute of Geology and Geophysics, chinese academy of sciences, Key Laboratory of Engineering Geomechanics, {3. 100029, china 3. School of Geoscience & Environmental Engineering, Central South University, Changsha 410083. china 1. china Non-ferrous Metals resource geological Survey Beijing 100012 China 2. institute of Geology and Geophysics Chinese Academy of Sciences Key Laboratory of Engineering Geomechanics Beijing 100029 China 3. School of Geoscience & Environmental Engineering Central South University Changsha 410083 China

geological condition and rainfall are two most principal conditions inducing landslides in the Chongqing region. By analyzing the forming conditions of rainfall-induced landslides, a new method for spatio-temporal prediction of rainfall-induced landslide is brought forward on the basis of grading and overlapping geological condition and rainfall factor in this paper. At first, semi-quantitative assessment and grading for the geological condition of a certain area or slope can be carried out with the multi-factor interactive matrix. Then the severity of rainfall in that area is grading according to the maximum daily rainfall and the total rainfall in a rainfall course. Finally, the “landslide probability judgement factor” can be worked out through grading and overlapping “geological condition influenc- ing factor” and “rainfall influencing factor”, by which the landslide can be graded into 4 grades, they are landslide extremely easily happening, landslide easily happening, landslide difficultly happening and landslide hardly ever happening respectively. More accurate spatio-temporal prediction of rain- fall-induced landslides can come true on the ground of detailed geological survey of some dangerous slopes in an area and more precise weather forecast. Finally, the reliability and feasibility of carrying out the spatio-temporal prediction of rainfall-induced landslides with the method of “two factors” grading and overlapping are validated by the example of Jipazi landslide.

关键词： rainfall-induced landslide, geological condition, rainfall, two factors, grading and overlapping, interactive matrix, spatio-temporal prediction.

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Seismic multi-arch structures in East china

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Science china Earth sciences 2006年第2期49卷 133-146页

作者： YANG Wencai1 & CHEN Zhide2 1.institute of Geology, chinese academy of geological sciences, beijing 10003.,{3. 2.Daqing institute of Petroleum Exploration and Production, Daqing 163.12,{3. 1. institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China 2. Daqing institute of Petroleum Exploration and Production Daqing 163712 China

In previous papers (Wencai, 2002, 2003., the author has analyzed the deep seismic reflection profiles along some of the Mesozoic plutons in East china, and has pointed out that the crustal structures around these intrusions usually correlate with a special seismic fabric called the seismic multi-arch structure. This paper will continue to show main characteristics of the seismic multi-arch structures and discuss their relationship with mantle-origin magmatism and the lithospheric thinning process. Calibration of seismic reflectors in chinese continental drilling sites shows that small-scale arch-like reflectors can be generated by fractured eclogites or other plutons, they do not belong to the multi-arch structure specially discussed in the paper. The multi-arch structure is char-acterized by several arch-like reflectors distributed in both the upper and lower crust with granitoid plutons or stocks exposed on the surface, which do not have obvious negative Europium anomalies. Based on the distribution pattern of arch reflectors, the multi-arch magmatic structures can be divided into three main types, namely the simple vertical combination type, the spread arch magmatic struc-ture and the arch-bouquet structure. All of them correlate to mantle-origin magmatism, but occur in different places. The spread arch magmatic structures occur within a Mesozoic/Cenozoic rift zone with very thin and hot lithosphere. The vertical combination type of the multi-arch structures occurred near the rift zones where lithosphere was thin and hot. The arch-bouquet magmatic structures occur far from the rift zones where the lithosphere is not hot. The continental rifting acted as the late episode of the lithospheric thinning process seeing that the rift zones usually coincide with the thinnest parts of the lithosphere in East china. In different locations within the lithospheric thinning areas, mantle-origin magmatic activities have different characteristics, which might generate different

关键词： deep seismic reflection, multi-arch structure, eclogite bodies, mantle-origin magmatism, East china.

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A Study of Mesoproterozoic Iron Cosmic Micro-spherules from 1.8 Ga and 1.6 Ga Old Strata in the Ming Tombs District,beijing

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Acta Geologica Sinica(English Edition) 2007年第4期81卷 649-657页

作者： SONG Tianrui HE Zhengjun WAN Yusheng and LIU Yanxue institute of Geology,chinese academy of {3. sciences,beijing 10003. institute of Geology Chinese Academy of Geological Sciences Beijing 100037

Numerous iron cosmic micro-spherules have been discovered from Mesoproterozoic strata including the Changzhougou Formation （1.8 Ga） and the Dahongyu Formation （1.6 Ga） of the Ming Tombs district, beijing. There are 1 to 3. grains of cosmic spherules per 2 kg of a sandstone sample taken from the bottom of a coarse sandstone bed of the Changzhougou Formation and 56 grains per 3.69 kg of a rock sample from silicified carbonate rocks of the Dahongyu Formation. The surface textures of cosmic spherules analyzed by means of the secondary electron imagery are identical with those reported from references either domestic or abroad. So far the geo-ages of 1.8 Ga and 1.6 Ga of cosmic spherules from the Changzhougou and Dahongyu formations might be older than those reported in the world. Table 1 gives the electron probe analysis data of cosmic spherules for 3. spherule grains and 44 testing points as follows （%）： FeO, 80-95; Cr2O3. 0-9.56; NiO, 0-0.78; CoO, 0-0.46; indicating that the Cr2O3.content is higher and FeO content lower in the Changzhougou Formation than in the Dahongyu Formation. The helium isotopic data of cosmic spherules as well as their host rocks vary greatly between the Changzhougou and the Dahongyu formations as shown in Table 2. The data of cosmic spherules of the Changzhougou Formation vs the Dahongyu Formation are 57.5/1.23.in ^3.e/^4He （10^-8）; and 55.54/809.60 in ^4He （10^-6cm^3.TP/g）; those of coarse sandstone of the Changzhougou Formation vs silicified carbonate of the Dahongyu Formation are 3.3./2.59 in ^3.e/^4He （10^-8） and 4.56/2.3. in ^3.e （10^-6cm^3.TP/g）. The ratio of analytic data of helium isotopes are different for cosmic spherules and their host rocks; for example, the ^3.e/^4He （10^-8） values are 16.96 and 0.48, and the ^4He （10^-6 cm^3.TP/g） are 12.18 and 3.5.98 for the Changzhougou and Dahongyu formations respectively. It was reported that the world＇s oldest micrometeorites had been found in the Meso-Proterozoic Satakunta Formation, Finland

关键词： Proterozoic cosmic spherule helium isotopes extraterrestrial material carbonaceous chondrite

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An Experimental Study on Three Quaternary Phases in the Fe-Sn-Sb-S System: Pb-Free Franckeite, Pb-Free Cylindrite and (Fe, Sb)-Ottemannite s.s.

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Acta Geologica Sinica(English Edition) 1988年第4期1卷 393-405页

作者： Li Jiuling Huang Jiashan Zhou Kezi Zhang Guilan institute of Mineral Deposits, chinese academy of geological sciences, beijing institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing

Experimental studies on the two solid solutions franckeite s.s. and cylindrite s.s. yielded among others thePb-free endmembers of franckeite and cylindrite respectively. In these endmembers the lead content of the twomineral phases are completely substituted by bivalent tin. A third phase, ottemannite s.s. with （Fe. Sb）-bearingcompositions, was further identified in the Pb-free 4-component system Fe-Sn-Sb-S. Pb-free franckeite andcylindrite could only be synthesized as homogeneous phases at high temperatures. The ottemannite s.s. was ob-tained at 600℃ but an extensive existing range was also confirmed at temperatures below 500℃. The phase relations were discussed in the pseudoternary subsystem SnS-SnS2-FeSb2S4. The following se-quence of Pb-free phases and phase assemblages were observed under increasing Sn4+content at 600℃:herzenhergite （SnS）+franckeite, franckeite, franckeite+cylindrite, cylindrite, cylindrite+（Fe, Sb）-ottemannite.（Fe, Sb）-ottemannite. （Fe. Sb）-ottemannite+berndtite （SnS2）. The assemblage cylindrite+berndtite was identi-fied in synthetic systems involving Pb. The phase Fe. Sb-ottemannite s.s. appears to be stable only under Pb-de-ficient and high sulfur fugacity conditions.

关键词： Pb-Free Franckeite An Experimental Study on Three Quaternary Phases in the Fe-Sn-Sb-S System Ottemannite s.s Fe Sb Sn

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Mesozoic thrusts and extensional structures in the Daqingshan orogen, Inner Mongolia, and their temporal and spatial relationship

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Progress in Natural Science:Materials International 2007年第2期17卷 177-186页

作者： QI Guowei, ZHANG Jinjiang , WANG Xinshe and GUO Lei ( Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, china School of Earth and Space sciences, Peking University, beijing 100871, china institute of Geology, chinese academy of geological sciences, beijing 10003., china) [a]Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education China [b]School of Earth and Space sciences Peking University Beijing China [c]chinese academy of geological {3. Institute of Geology Beijing China

Three large-scale thrusts developed in the Daqingshan orogen, Inner Mongolia, with a northeast-east trending from Louhuashan to Suletu are described in this paper. These northwest-directed thrusts, together with the four tectonic belts (or tectonic sheets) separated by these faults, formed a typical thrusting system. The originally defined Hohhot metamorphic core complex may be a tectonic sheet, making the uppermost tectonic unit of the thrusting system and truncated by the Daqingshan detachment fault on top. The existing tectono-chronological studies showed that the thrusting of this region possibly happened at the same time as the extension along the top detachment fault. This presents that the contraction and extension in Daqingshan orogen were probably simultaneous. The structural pattern of the Daqingshan orogen can be correlated to the Himalayan orogen, and models for simultaneous thrusting and detachment in Himalaya may give a hint for explaining the development of the Daqingshan orogen.

关键词： Daqingshan thrust metamorphic core complex detachment fault contraction-extension transform Himalaya.

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Geochemical Characteristics of Granitoids in the Eastern Sector of the Northern Tianshan Mountains in Xinjiang

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Acta Geologica Sinica(English Edition) 1990年第1期64卷 55-67页

作者： Wang Bixiang Li Zhaonai Zhao Guangzan Wang Fubao Zhang Shuizhe Fei Wenheng institute of Geology, chinese academy of geological sciences, beijing institute of Geology Chinese Academy of Geological Sciences Beijing

The granitioids in question are located in the geosynclinal fold belt of the Northern Tianshan Mountains.The magmas are intruded into a Carboniferous marine volcanic-sedimentary rock series. forming a contempo-raneous. intermediate-basic to acid. composite intrusion. With a whole-rock Rb-Sr isochron age of 3.5.7 Ma. itis considered to be of middle Heicynian age. The granitoids have a SiO_2 content of 48-78%, a calc-alkali indexof 60 and silica-alkali indices ρ=2.2-2.4 and σ=1.5-2. From basic to acid compositions, the total REE con-tent increases from 3. to 143.ppm. δEu ranges from 0.47 to 0.86 and the Eu anomalies are negative. Thenormalized curves of REE of various rock types are very similar. These coupled with the characteristics of traceelement geochemistry show that the intrusion is an island arc-continental margin, calc-alkaline one. Theδ^(18)O values range from 5.8 to 8.9‰ and the ^(87)Sr/^(86)Sr initial ratio is 0.705. The materials of the intrusion arecomposed of a mixture of the magmas at the top of the upper mantle and in the lower crust, This indicates thatthe rocks might be consanguineous. differentiated and evolved products and possess the characteristics of Ⅰtype granites.

关键词： Geochemical Characteristics of Granitoids in the Eastern Sector of the Northern Tianshan Mountains in Xinjiang

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Himalayan Tectonic Evolution in the East Asian Peri-Pacific Region

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Acta Geologica Sinica(English Edition) 1990年第3期64卷 233-246页

作者： Cui Shengqin Li Jinrong institute of Geomechanics, chinese academy of {3. Scinences, beijing Fei Zhenbi institute of Geornechanics Chinese Academy of Geological Scinences Beijing

This paper summarizes the Late Palaeozoic. Indosinian and Yanshanian palaeotectonic settings in theperi-Pacific region of East Asia. On that basis, the Himalayan crustal movement in the region is divided intothe early and late tectonic stages and two principal tectonic phases. From the ocean to the continent, 5 giganticHimalayan formation-deformation belts are distinguished; they are the Northwest Pacific trench-island arcbelt. the Northwest Pacific marginal sea basin bell. the East china Sea-northern South china Seacontinental-shelf down-faulted belt. the East Asian epicontinental rift belt. and the East Asian intracontinentalrift belt. The Early and Late Himalayan tectonic evolution is dealt with. Finally the state of the Himalayan re-gional stress field and its evoution in the region are discussed. It is considered that the mechanism of their for-mation is closely related to the continent-ocean and surface-deep earth interaction.

关键词： Asia

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Geomorphologic evidence of phased uplift of the northeastern Qinghai-Tibet Plateau since 14 million years ago

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Science china Earth sciences 2004年第9期47卷 822-833页

作者： LU Huayu1, WANG Xiaoyong1, AN Zhisheng1, MIAO Xiaodong1, ZHU Rixiang3. MA Haizhou2, LI Zhen4, TAN Hongbing2 & WANG Xianyan1 1. State Key Laboratory of Loess and Quaternary Geology, institute of Earth Environment, chinese academy of {3., Xi’an 710075 china 2. Qinghai institute of Salt Lakes, chinese academy of {3.. Xining 810008, china 3. institute of Geology and Geophysics, chinese academy of {3., beijing 100029, china 4. Department of Geography, Qinghai Normal University, Xining 810008, china chinese Acad Sci Inst Earth Environm State Key Lab Loess & Quaternary Geol Xian 710075 Peoples R China chinese Acad Sci Qinghai Inst Salt Lakes Xining 810008 Peoples R China chinese Acad Sci Inst Geol & Geophys Beijing 100029 Peoples R China Qinghai Normal Univ Dept Geog Xining 810008 Peoples R China

A typical sequence of fluvial terraces and aeolian deposits overlying these ter- races were multidisciplinary investigated. New evidences for uplift process of the northeastern Qinghai-Tibetan Plateau in the past 14 million years were obtained. At least 11 river terraces along Huangshui, the first-class tributary of Yellow River, at the Xining-Huzhu region are identi- fied. While the first one (T1) is classified as an accumulation terrace, the others are all basement river terraces, which consist of the Tertiary sandstone and siltstone bedrock, fluvial gravel and pebbles and the overlying aeolian loess-Red Clay deposit. Samples from the aeolian deposits were examined for paleomagnetic stratigraphic reconstruction (103. samples), luminescence dating (16 samples), magnetic susceptibility and grain-size distribution (more than 4000 sam- ples). The luminescence dating and stratigraphic correlation suggest that terraces of Tll, T10, T8, T7, T3. T2, T1 were formed at 14, 11.3. 1.55, 1.2, 0.15, 0.07 and 0.01 million years ago, re- spectively. Sedimentological analysis and geomorphological observation indicate that formation and evolution of these terraces were mainly driven by tectonic uplift. Therefore, the terrace se- quence provides an ideal geological record, of the uplift process of the northeastern during the past 14 million years, and the timings of the terraces formation are regarded as the timings of tectonic uplift. The significant uplifting events took place at 14, 11.3. 1.2 and 0.15 mil- lion years ago, respectively. The fluvial incision at the Xining-Huzhu region is less than 100 m during a period of ~12 million years in the Miocene era (between the Tll and T9), while the Huangshui River had incised 43. m during the past 1.2 million years (from T7 to the present floodplain). The river incision process clearly demonstrates that accelerated rising of the north- eastern Qinghai-Tibet Plateau during the late Cenozoic, and provides new evidence of previous thoughts

关键词： river terrace, tectonic uplift, loess-Red Clay, the past 14 million years, northeastern Qinghai-Tibet Plateau.

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