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The role of aerial algae in the formation of the landscape of the Yunnan Stone Forest,Yunnan Province, china

Science china earth sciences 2004年第9期47卷 846-864页

作者： TIAN Youping1,3. ZHANG Jie2, SONG Linhua1 & BAO Haosheng2 1. Institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, beijing 100101, {3. 2. Department of Geography, Nanjing University, Nanjing 210093. {3. 3. school of earth sciences and Resources, {3. University of Geosciences, beijing 100083. china Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China school of earth sciences and Resources China University of Geosciences Beijing China Department of Geography Nanjing University Nanjing China

Aerial algae on the surface of carbonate rocks at the Stone Forest, Shilin County, Yunnan Province, china, and their bioerosion were investigated in the field and studied in the laboratory in detail. Through the observation, identification and statistics of more than one hun- dred algal samples and rock samples with the optical microscopes (stereomicroscope, biological microscope) and the scanning electronic microscope (SEM), the relationships between erosional forms on the surface of the Stone Forest and algae and/or algal communities and the genetic mechanism for the formation of erosional forms were analyzed. It is suggested that aerial algae play an active role in bioerosive processes that may affect the formation of karst erosional forms. These effects include both direct and indirect ones. The direct effect is the initiative control (algal shape-controlling role) of algae on the formation of karst forms of various scales, mostly mi- cro-scale (3.) and minor-scale (10-3.10-1m) erosional forms. The algal shape-controlling roles can be divided into the algal individual shape-controlling role and the algal community shape-controlling role. The former mostly controls the formation of micro-scale erosional forms, while the latter mostly controls the formation of micro-scale and smaller minor-scale erosional forms. The indirect effect refers to the promoting role of algae in the formation of karst forms, which may affect the formation of karst forms of all types and scales. The bioerosion of algae accelerates the weathering process of the whole Stone Forest karst landforms.

关键词： aerial algae, bioerosion, the Stone Forest, Yunnan Province, china.

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Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts

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Chinese Science Bulletin 2009年第22期54卷 4148-4160页

作者： NIU Yaoling1,2,3.1 Department of earth sciences, Durham University, Durham DH1 3.E, UK 2 school of earth sciences and Resources, china University of Geosciences, beijing 100083. china 3.school of earth and Space sciences, Peking University, beijing 100871, china Department of earth sciences Durham University Durham DH1 3LE UK school of earth sciences and Resources China University of Geosciences Beijing 100083 China school of earth and Space sciences Peking University Beijing 100871 China

Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with "hotspots" or "mantle plumes". While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis, our current understanding on the origin of OIB source material remains unsatisfactory, and some prevailing ideas need revision. One of the most popular views states that OIB source material is recycled oceanic crust (ROC). Among many problems with the ROC model, the ocean crust is simply too depleted (e.g., [La/Sm]PM > 1) OIB. Another popular view states that the enriched component of OIB comes from recycled continental crust (RCC, i.e.; terrigenous sediments). While both CC and OIB are enriched in many incompatible elements (e.g., both have [La/Sm]PM >>1), the CC has characteristic enrichment in Pb and deletion in Nb, Ta, P and Ti. Such signature is too strong to be eliminated such that CC is unsuitable as source material for OIB. Plate tectonics and mantle circulation permit the presence of ROC and RCC materials in mantle source regions of basalts, but they must be volumetrically insignificant in contributing to basalt magmatism. The observation that OIB are not only enriched in incompatible elements, but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism. H2O and CO2 rich incipient melt may form in the seismic low velocity zone (LVZ). This melt will rise because of buoyancy and concentrate into a melt rich layer atop the LVZ to metasomatize the growing lithosphere, forming the metasomatic vein lithologies. Erupted OIB melts may have three components: (1) fertile OIB source material from depth that is dominant, (2) the melt layer, and (3. assimilation of the metasomatic

关键词：岩石成因论海洋 OIB 矿物学

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Petrogenesis and dating of the Kangding complex,Sichuan Province

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Science china earth sciences 2005年第5期48卷 622-634页

作者： CHEN Yuelong 1 , LUO Zhaohua 1 , ZHAO Junxiang, LI Zhihong, ZHANG Hongfei & SONG Biao 3.1. Faculty of earth sciences and Natural Resources, china University of Geosciences, beijing 100083. china 2. Faculty of earth sciences, china University of Geosciences, Wuhan 43.074, china 3. beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological sciences, beijing 10003., china Faculty of earth sciences and Natural Resources China University of Geosciences Beijing China Faculty of earth sciences China University of Geosciences Wuhan China beijing SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences Beijing China

An analysis of major and trace element geochemistry and SHRIMP U-Pb zircon dating of mafic, intermediate, and felsic rocks from the Mianning metamorphic complex of Si- chuan Province was conducted. One of our conclusions is that a majority of the zircons crystal- lized between 721 and 773.Ma in a magmatic regime. The complexes contain early to late Pa- leo-proterozoic relict zircons from ancient continental crust. The oldest age, 2468 Ma, may rep- resent the basement of the Yangtze block. Overgrowth zircon rims and palingenetic zircons have been observed and dated, and are believed to have formed after crystallization, during Paleozoic and Mesozoic metamorphic-anatexis. We also conclude that depletion of Nb, Ta, HREE, in a spider-diagram normalized to primitive mantle and calc-alkaline association, implies that they formed in island-arc or under-plating settings.

关键词： Kangding complex, zircons, SHRIMP, tectonic setting.

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Indian Ocean-MORB-type isotopic signature of Yushigou ophiolite in North Qilian Mountains and its implications

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Science china earth sciences 2006年第6期49卷 561-572页

作者： HOU Qingye1,2, ZHAO Zhidan1,2, ZHANG Hongfei3. ZHANG Benren3.& CHEN Yuelong2 1. State Key Laboratory of Geological Processes and Mineral Resources, china University of Geosciences, beijing 100083. china 2. {3. of earth Science and Mineral Resources, china University of Geosciences, beijing 100083. china 3. Faculty of earth sciences, china University of Geosciences, Wuhan 43.074, china State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing China school of earth Science and Mineral Resources China University of Geosciences Beijing China Faculty of earth sciences China University of Geosciences Wuhan China

In order to explore the disputed issue concerning the tectonic affinity ofthe ancient ocean mantle of North Qilian Mountains (NQM), geochemical and Sr, Nd, Pb isotopiccompositions of pillow basalts of the Yushigou Ophiolite (YSGO) suite from NQM have been analyzedsystematically. The pillow basalts exhibit tholeiitic characteristics, with flatchondrite-normalized REE patterns ((La/Yb)_N = 0.98—1.27). They display no Nb, Ta, Zr, Hf negativeanomalies, and show MORB features in 2Nb-Zr/4-Y and Ti/100-Zr-YX3.tectonic discrimination *** results indicate that the Yushigou ophiolite is most likely to be formed in a mid-ocean ridgeor mature back-arc basin. Their isotopic data show a relatively broad and enriched ^(87)Sr/^(86)Sr(0.70509 — 0.70700), restricted ^(143.Nd/^(144)Nd (0.512955-0.512978). Pb isotopes are in the rangeof ^(206)Pb/^(204)Pb (18.054-20.562), ^(207)Pb/^(204)Pb (15.53.-15.743. and ^(208)Pb/^(204)Pb(3..068-3..53.). These isotopic data imply that the basalts originated from the depleted mantle(DMM), with the involvement of enriched mantle components (mainly EMII). Geochemical comparisonsbetween the basalts in YSGO and the MORB-type basalts of ophiolite suites occurring in the knownancient Tethyan tectonic domain indicate that the ancient oceanic mantle represented by YSGO suiteforming in early Paleozoic in the North Qilian Moutains is very similar to the Tethyan mantle inboth trace elements and isotopic compositions. The North Qilian Mountains should be a part of theTethyan tectonic domain in early Paleozoic. This further implies that the Tethyan tectonic domaincan be deduced to early Paleozoic in the study area, which will be helpful to discussing thetectonic affinity and evolution of the North Qilian Mountains.

关键词： geochemistry, Indian Ocean-MORB-type isotopic signatures, Tethyan tectonic domain, Yushigou ophiolite, North Qilian Mountains.

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South china's Gondwana connection in the Paleozoic:Paleomagnetic evidence

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Progress in Natural Science:Materials International 2004年第1期14卷 86-91页

作者： ZHANG Shihong*(school of earth sciences and Resources, {3. University of Geosciences, beijing 100083. china) school of earth sciences and Resources China University of Geosciences Beijing 100083 China

The reconstruction in which the South china Block (SCB) lies along the Great India Australia region of Gondwana margin is tested by using existing Paleozoic paleomagnetic data. Under the proposed reconstruction, all six high quality paleopoles from the SCB between the Early Cambrian and late Early Devonian (～400 Ma) are in good agreement with coeval paleopoles from Gondwana. Thereafter, the apparent polar wander paths for the SCB and Gondwana diverge markedly. This indicates that the SCB had been part of Gondwana and the connection was intact from at least Early Cambrian until late Early Devonian, but they began to separate by late Middle Devonian (～3.5 Ma).

关键词： South china block Gondwana paleomagnetism reconstruction

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The mathematical model of wetting angle of heterogeneous nucleation

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Science china(Technological sciences) 2004年第4期47卷 391-397页

作者： HUANG Cheng1, SONG Bo1, MAO Jinghong2 & ZHAO Pei3.1. school of Metallurgical and Ecological Engineering, University of Science and Technology beijing, beijing 100083. china 2. school of Material Science, University of Science and Technology beijing, beijing 100083. china 3. Central Iron and Steel Research Institute, beijing 100081, china school of Metallurgical and Ecological Engineering University of Science and Technology Beijing school of Material Science University of Science and Technology Beijing

The heterogeneous nucleation has been analyzed in terms of the thermodynamic theory, and the mathematical model of wetting angle of heterogeneous nucleation has been developed based on the dynamic requirements of hetero- and homogeneous nucleation. With the wetting angel model, the wetting angles of different catalysts in liquid iron have been calculated. The result shows that the wetting angle of most catalysts is smaller than 40, and the value of f() is far less than 1. The wetting angles of TiN, TiC and RE2O3.are smaller, while the wetting angle of MnO is bigger among the ordinary nucleation catalysts. The wetting angles calculated by this model are in agreement with the results of other research work.

关键词： heterogeneous nucleation, mathematical model, wetting angle, undercooling.

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Comparative study on CO_2 corrosion behavior of N80,P110,X52 and 13.r pipe lines in simulated stratum water

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Science china(Technological sciences) 2010年第9期53卷 2342-2349页

作者： CAI YiDong1,GUO PengChao1,LIU DaMeng1,CHEN ShiYu2 & LIU JunLai3.1 school of Energy Resources,china University of Geosciences,{3. 100083.china 2 school of Materials Science and Engineering,University of Science and Technology {3.,{3. 100083.china 3.school of earth sciences and Resources,china University of Geosciences,{3. 100083.china school of Energy Resources China University of Geosciences

To better understand the carbon dioxide (CO2) corrosion behavior of carbon steel and its influence on petroleum development (including drilling,production and transportation) in the Daqing Oilfield,CO2 corrosion behaviors of N80,P110,X52 and 13.r pipe lines in simulated solution at high temperature and high pressure condition are investigated by dynamic corrosion experiments,scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) *** show that the corrosion rate of all pipe lines increases quickly when CO2 partial pressure increases from 0.5 to 1.5 MPa,but it slows down when CO2 partial pressure further increases from 1.5 to 4.5 MPa,during which localized corrosion is *** the experimental temperature ranges from 60 to 120°C,localized corrosion *** corrosion rate of all pipe lines decreases sharply when the temperature changes from 60 to 100°C,and it becomes stable after the temperature is higher than 100°*** the flow rate is in the range of 0–1.5 m/s,the corrosion rate of sample X52 remains unchanged,but localized corrosion gradually becomes very serious when the flow rate further *** analyzing the corrosion product scales of sample 13.r,some remarkable phenomena are *** the temperature range of 60–100°C,the corrosion product scales are loose and thick,but become very compact when the temperature increases above 100°*** the later case,localized corrosion is *** main components of the corrosion product scales are FeCO3.and Cr2O3.

关键词： CO2 corrosion pipe lines weight loss SEM EDS

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Discovery of a pterodactylid pterosaur from the Yixian Formation of western Liaoning,china

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Chinese Science Bulletin 2001年第13期46卷 1112-1117页

作者： WANG Xiaolin & LU Junchang1. Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of sciences, beijing 100044, china 2. College of {3. sciences and Resources, china University of Geo-sciences, beijing 100083. china 3. Department of Geological sciences, Southern Methodist University, Dallas, TX 75275, USA Institute of Vertebrate Paleontology Chinese Academy of Sciences Beijing 100044 China

A well-preserved pterosaur with nearly complete skull is described from the Lower Cretaceous Yixian Formation at Sihetun in western Liaoning. It is characterized by a low and long crestless skull, slender and pointed teeth, long metacarpal, nearly equal length of metatarsals I -III and short pedal digit V. It is referred to a new genus and species of the family Pterodactylidae: Haopterus gracilis gen. et sp. nov. This is the first pterosaur with a nearly complete skull from the Jehol Biota; it also represents the first non-controversial fossil record of Pterodactylidae in Asia. Haopterus is more derived than Pterodactylus from the Late Jurassic Solnhofen in Germany. This discovery extends the distribution of the family Pterodactylidae from Europe and Africa to Asia and its latest occurrence from the Late Jurassic to the Early Cretaceous. The discovery of Haopterus gracilis provides further evidence for the study of the originand radiation of the Jehol Biota; it also sheds new light on the evolution and

关键词： western Liaoning Early Cretaceous Yixian Formation Pterodactylidae.

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A tentative study for the prediction of the CME related geomagnetic storm intensity and its transit time

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Science china(Technological sciences) 2005年第6期48卷 648-668页

作者： ZHAO Xinhua1,2 & FENG Xueshang1,3.1. SIGMA Weather Group, Key Laboratory of Space Weather, Center for Space Science and Applied Re-search, Chinese Academy of sciences, beijing 100080, china 2. Graduate {3. of the Chinese Academy of sciences, beijing 10003., china 3. {3. of Geophysics and Geoinformation Systems, china University of Geosciences, beijing 100083. china SIGMA Weather Group Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China Graduate school of the Chinese Academy of sciences Beijing China school of Geophysics and Geoinformation Systems China University of Geosciences Beijing China

Using 80 CME-ICME events during 1997.1―2002.9, based on the eruptive source locations of CMEs and solar magnetic field observation at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to study the propagation of CME and its geoeffectiveness. In context of this coordinate system, the effect of the eruptive source location and the form of heliospheric current sheet (HCS) at the eruptive time of CME on the geomagnetic storm intensity caused by CME and the CME’s transit time at the earth is investigated in detail. Our preliminary conclusions are: 1) The geomagnetic disturbances caused by CMEs tend to have the so-called “same side-opposite side effect”, i.e. CMEs erupt from the same side of the HCS as the earth would be more likely to arrive at the earth and the geomagnetic disturbances associated with them tend to be of larger magnitude, while CMEs erupting from the opposite side would arrive at the earth with less probability and the corresponding geomagnetic disturbance magnitudes would be relatively weaker. 2) The angular separation between the earth and the HCS affect the corresponding disturbance intensity. That is, when our earth is located near the HCS, adverse space weather events occur most probably. 3. The erupting location of the CME and its nearby form of HCS will also affect its arrival time at the earth. According to these conclusions, in this context of CMC coordinate we arrive at new prediction method for estimating the geomagnetic storm intensity (Dstmin) caused by CMEs and their transit times. The application of the empirical model for 80 CME-ICME events shows that the relative error of Dst is within 3.% for 59% events with Dstmin≤?50 nT, while the averaged absolute error of transit time is lower than 10 h for all events.

关键词： coronal mass ejections, current sheet magnetic coordinate system, geomagnetic storm intensity, transit time, prediction method.

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Experimental remolding on the caprock's 3. strain field of the Indosinian-Yanshanian epoch in Tongling deposit concentrating area

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Science china earth sciences 2005年第7期48卷 863-874页

作者： DENG Jun1,HUANG Dinghua2,WANG Qingfei1,WAN Li1,SUN Zhongshi3.YANG Liqiang1 & GAO Bangfei1 1. State Key Laboratory of Geological Processes and Mineral Resources,china University of Geosciences,beijing {3.china 2. Faculty of earth sciences,china University of Geosciences,Wuhan 43.074,china 3. Department of earth sciences,Jilin University,Changchun 13.061,china State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 China Faculty of earth sciences China University of Geosciences Wuhan 430074 China Department of earth sciences Jilin University Changchun 130061 China

Based on field observations and rheology analysis, we perform one analogue experiment and remold the 3. structural frame of Tongling deposit concentrating area firstly. Then we disassemble and dialyze the 3. structures of the model using the methods of "slicing" and "stripping". A series of sliced planes vertical to the fold hinges show similar landscapes of that in the drill hole profiles. Meanwhile, layer stripping analysis indicates that the deformation features of each layer in the model are qualitatively analogical to those obtained from field observations. Through contrasting the 3. structure between the experimental model and the field phenomena, we verify the following 3. deformation features of the caprock in this area: (1) the Tongling area mainly consists of three series of NE S-typed fold groups; (2) in the uniform stress field, the incoherent folds universally develop in different positions, along different axes as well as in different strata; (3. the faults propagate upward which are mostly inter-bedded detachment faults, while the fold amplitudes decrease while going deeper; and (4) the folds and cleavages are highly developed in the Silurian System indicating that the deformation effect of the Indosin-ian-Yanshanian structural layer terminates at this layer, which suggests that the Silurian System is the crucial layer for the inversion between brittle and plastic deformation domains and the underlying strata are subject to the control of another deformation system with distinct properties.

关键词： Tongling deposit concentrating area Indosinian-Yanshanian epoch 3. structural frame of the caprock analogue experiment slicing and stripping analysis structural model.

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