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Geomorphologic evidence of phased uplift of the northeastern Qinghai-Tibet Plateau since 1. 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, {1. of Earth Environment, Chinese Academy of Sciences, Xi’an 71.075{1. 2. Qinghai {1. of {3. lakes, Chinese Academy of Sciences. xining 81.008,{1. 3. {1. of Geology and Geophysics, Chinese Academy of Sciences, Beijing 1.0029,{1. 4. Department of Geography, Qinghai Normal University, xining 81.008,{1. 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 1. million years were obtained. At least 1. 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 (1.{1. samples), luminescence dating (1. samples), magnetic susceptibility and grain-size distribution (more than 4000 sam- ples). The luminescence dating and stratigraphic correlation suggest that terraces of Tll, T1., T8, T7, T{1. T2, T1.were formed at 1., 1..{1. 1.55, 1.2, 0.1., 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 1. million years, and the timings of the terraces formation are regarded as the timings of tectonic uplift. The significant uplifting events took place at 1., 1..{1. 1.2 and 0.1. mil- lion years ago, respectively. The fluvial incision at the xining-Huzhu region is less than 1.0 m during a period of ~1. million years in the Miocene era (between the Tll and T9), while the Huangshui River had incised 4{1. 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 1. million years, northeastern Qinghai-Tibet Plateau.

Characteristics of chlorine isotope distribution and analysis on sylvinite deposit formation based on ancient salt rock in the western Tarim Basin

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Science china Earth Sciences 2005年第11期48卷 1913-1920页

作者： TAN Hongbing1.2, MA Haizhou1. XIAO Yingkai1. WEI Haizhen1.2, ZHANG Xiying1.& MA Wandong1.1. institute of {1. lakes, Chinese Academy of Sciences,{3., china 2. Graduate School of the Chinese Academy of Sciences, Beijing 1.003., china 1. institute of {1. lakes Chinese Academy of Sciences 810008 Xining China 2. Graduate School of the Chinese Academy of Sciences 100039 Beijing China

During formation of the Tarim Basin, there repetitively happened seawater invasion for it was ever connected with wide Paleo-mediterranean Sea. At the same time, for the applica-tion of tectonic and paleoenvironmental condition, the basin deposits many sequences of thick strata of evaporites, especially in its two largest subbasins of Kuqa in the north and Shaqa in the southwest. Therefore, the western Tarim Basin has been considered to be a favorable location to prospect ancient sylvinite deposit. But it is unfortunate that the Br×1.3.Cl ratio, as a common geochemical index to uncover clues of sylvinite deposit, is almost invalid to indicate the stage of ancient brine condensation for very low content of bromine in {1. rock samples (less than 1.?6 commonly) in the western Tarim Basin evaporites. Fortunately, we noticed recently that the val-ues of chlorine isotope (δ 3.Cl value) for {1. rock samples follow some clear laws from place to place, which in the Shaqa subbasin, all δ 3.Cl values of {1. rock samples behaved negatively and on the contrary, they all surprisingly showed positive values in the Kuqa subbasin. Based on conclusions of previous research and referring to the ratios of Br×1.3.Cl for {1. rock or brine samples, we proved that the chlorine isotope (δ 3.Cl) could be used as an effective index to find ancient sylvinite deposit in those evaporites rock basin with low content of Br element back-ground, such as the Tarim Basin. Thus according to the new index of chlorine isotope, we con-clude that the concentration of ancient brines formed ancient {1. rocks is much more concen-trated in the Shaqa subbasin than that in the Kuqa subbasin. Particularly, the δ 3.Cl value of {1. rock in Kashi depression of the western Shaqa subbasin is greatly negative (1.00‰), which may predicate that the ancient brine has been concentrated to the terminal stage of {1. deposit or even the later stage of sylvinite deposit. Then it is possible to find sylvinite-bearing d

关键词： the Tarim Basin, chlorine isotope, ancient salt rock, ancient sylvinite deposit, deposit stage

An unusual isotopic fractionation of boron in synthetic calcium carbonate precipitated from seawater and saline water

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Science china Chemistry 2006年第5期49卷 454-465页

作者： XIAO Yingkai1.2,LI Shizhen1.WEI Haizhen1.SUN Aide1.ZHOU Weijian2 & LIU Weiguo2 1. Qinghai institute of {1. lakes,Chinese Academy of Sciences,{3. 81.008,china 2. State Key Laboratory of Loess and Quaternary Geology,institute of Earth Environment,Chinese Academy of Sciences,Xi’an 71.075,china 1. Qinghai institute of {1. lakes Chinese Academy of Sciences Xining 810008 China 2. State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China

Inorganic calcium carbonate precipitation from natural seawater and salinewater at various pH values was carried out experimentally. The results show the clear positiverelationships between boron concentration and δ^(1.)B of inorganic calcium carbonate with the pH ofnatural seawater and saline water. However, the variations of boron isotopic fractionation betweeninorganic calcite and seawater/saline water with pH are inconsistent with the hypothesis thatB(OH)_4^- is the dominant species incorporated into the biogenic calcite structure. The isotopicfractionation factors a between synthetic calcium carbonate precipitate and parent solutionsincrease systematically as pH increases, from 0.9884 at pH 7.60 to 1.0072 at pH 8.60 for seawaterand from 0.9826 at pH 7.60 to 1.01.8 at pH 8.75 for saline water. An unusual boron isotopicfractionation factor of larger than 1.in synthetic calcium carbonate precipitated fromseawater/saline water at higher pH is observed, which implies that a substantial amount of theisotopically heavier B(OH)_3.species must be incorporated preferentially into synthetic inorganiccarbonate. The results propose that the incorporation of B(OH)_3.is attributed to the formation ofMg(OH)_2 at higher pH of calcifying microenvironment during the synthetic calcium carbonateprecipitation. The preliminary experiment of Mg(OH)_2 precipitated from artificial seawater showsthat heavier ^(1.)B is enriched in Mg(OH)_2 precipitation, which suggests that isotopically heavierB(OH)_3.species incorporated preferentially into Mg(OH)_2 precipitation. This result cannot beapplied to explain the boron isotopic fractionation of marine bio-carbonate because of thepossibility that the unusual environment in this study appears in formation of marine bio-carbonateis infinitesimal. We, however, must pay more attention to this phenomenon observed in this study,which accidentally appears in especially natural environment.

关键词： boron, isotopic fractionation, calcium carbonate precipitate, seawater, saline water.

Influence of Fly Ash and Silica Fume on Water-resistant Property of Magnesium Oxychloride Cement

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Journal of Wuhan University of Technology(Materials Science) 2010年第4期25卷 721-724页

作者：李成栋于红发 Qinghai institute of {1. lakes Chinese Academy of Sciences Graduate School of Chinese Academy of Sciences Nanjing University of Aeronautics and Astronautics Department of Civil Engineering

By incorporation of fly ash or silica fume into magnesium oxychloride （MOC） cement, a high water resistance material can be formed for successful industrial applications. The influences of fly ash and silica fume on water-resistant property were investigated by SEM and EDS. It is found that the incorporation of fly ash or silica fume can improve the water-resistance of the MOC. The improvement of the water resistance of the MOC incorporated with fly ash or silica fume may be attributed to the alumino-silicate 5·1.8 gel or silicate 5·1.8 gel.

关键词： magnesium oxychloride cement fly ash silica fume water resistance

Study on phase diagrams and properties of solutions in ternary systems Li+,K+(Mg2+)/SO42--H2O at 25℃

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Chinese Journal of Chemistry 1995年第2期13卷 112-117页

作者： LI,Bing LI, Jun FANG, Chun-Hui WANG, Qing-Zhong SONG, Peng-ShengQinghai institute of {1. lakes, Chinese Academy of Sciences, {3., Qinghai 81.008, china SU.EDU Qinghai institute of {1. lakes Chinese Academy of Sciences Xining Qinghai 810008 China

Solubilities of ternary systems Li+,K+/SO42--H2O (1. and Li+,Mg2+/SO42-H2O (2) were investigated by isothermal method at 25℃. Physico-chemical properties of solutions, such as density, refractive index, viscosity, conductivity and pH, were determined. Phase diagram of the system (1. consists of three solubility branches and three crystallization fields corresponding to K2SO4, Li2SO4.H2O and LiKSO4. LiKSO4 is an incongruent compound, and its transition point is estimated graphically to be 45.5-46.0℃. No solid solution of LiKSO4 with Li2SO4.H2O was found in the system. The system (2) is a simple eutonic type. Pitzer model of electrolyte solution was used to check the obtained solubilities. Data comparison gives good agreement. Two equations were used to correlate density, refractive index of the solution with its composition. Differences between measured and calculated values are less than 0.6% for density, 0.1.% for the latter.

关键词： salt-water system solubility of Li salt phase diagram.

Thermodynamics of mixture of boric acid with lithium borate and chloride

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Chinese Journal of Chemistry 1994年第2期12卷 97-104页

作者： WANG, Dong-Bao SONG, Peng-Sheng The institute of {1. lakes, Chinese Academy of Sciences, {3., Qinghai 81.008, chinaYANG, Jia-ZhenDepartment of Chemistry, Liaoning University, Shenyang, Liaoning 1.003., china 1.he institute of {1. lakes Chinese Academy of Sciences Xining Qinghai 810008 China2Department of Chemistry Liaoning University Shenyang Liaoning 110036 China

The first thermodynamic dissociation constants of boric acid in aqueous solution of lithium chloride with borate at five different temperatures from 278.1. to 3.8.1. K were evaluated from emf values of the cell without liquid junction potential with the improved extrapolation and polynomial approximation on the basis of Pitzer's theory. Values obtained from both methods are in good agreement with each other. Pitzer's parameters β(0) and β(1. of LiB(OH)4 and other thermodynamic quantities of dissociation process of boric acid are obtained. Results have been discussed.

关键词： Thermodynamics boric aicd Pitzer's parameters.

THE HYDROCHEMICAL FEATURES OF salt {1. IN QAIDAM BASIN

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Chinese Journal of Oceanology and Limnology 1986年第4期4卷 383-403页

作者：于升松 institute of {1. lakes Academia Sinica xining

There are 3. {1. in the Qaidam Basin: 1.freshwater lake, 6 brackish-water {1., 2 saline-water {1. and 28 {3. *** pH value of {3. lake brines is 7.01. on the average, and the average total mineralization is 3.0.75 g/1. Their water bodies belong mainly to the five-component equilibrium system, :Na, K, Mg//SO4, Cl-H2O, which can be further grouped into sodium-magnesium sulfate subtype, magnesium sulfate subtype, chloride transition subtype and chloride type water by their hydrochemical property. The {3. lake brines of the first {3. forming epoch (N2-Q3. were of the sulfate type. In the second {3. forming epoch (Q3.Q4), some of them were of the chloride *** pH value of brines decreases with the increase of total mineralization. The pH value is lower when the total mineralization is from 50-3.0 g/1.and higher when the total mineralization is from 3.0-3.5 g/l, however, when the total mineralization is higher than 3.5 g/1. the pH value decreases slowly *** total mineralization of th

关键词： CI Lake THE HYDROCHEMICAL FEATURES OF salt {1. IN QAIDAM BASIN

Chronology of Holocene lacustrine sediments in Co Ngoin, central Tibetan Plateau

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Science china Earth Sciences 2006年第9期49卷 991-1001页

作者： WU Yanhong1. WANG Sumin1. HOU Xinhua1.3.1. Key Laboratory of Lake Sedimentation and Environment, Nanjing {1. of Geography and Limnology, Chinese Academy of Sciences, Nanjing 21.008,{1. 2. {1. of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 1.085,{1. 3. Graduate University of Chinese Academy of Sciences, Beijing 1.003.,{1. 1. Key Laboratory of Lake Sedimentation and Environment Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China 2. institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 10085 China 3. Graduate University of Chinese Academy of Sciences Beijing 100039 China

Chronology is the basis for using lacustrine sediments to reconstruct the history of en-vironmental change. Radioactive-nuclides such as 1.C, 21.Pb and 1.0}Cs dating are mainly used to establish the chronology for recent several ten thousand years. Because of being mixed with “dead carbon”, the measured 1.C age is always older than the actual age which is recognized as “reservoir effect”. Cs is a kind of active metal element, and easy to migrate vertically in the sediment that leads to the error of the time marker. 21.Pb dating should make sure to select CIC model or CRS model. On the Tibetan Plateau, most of the {1. are alkaline closed lake where Cs is more moveable in the sediment and the reservoir effect caused by “dead carbon” on 1.C dating is stronger. Based on the analysis on results of 1.C, 21.Pb and 1.0}Cs of the lacustrine sediments from Co Ngoin, central Tibetan Plateau, we use the simple regression method to re-calculate the 1.C calendar ages, and establish the time sequence for cores CE-1.and CE-2 with result of 21.Pb CRS model for the upper 3. cm and re-calculated 1.C calendar age for sediments bellow 3. cm. Since 1.00 cal. a BP, sedimentation inter-rupted for more than 1.00 years. According to this time sequence, variations of environmental proxies confidently reflect the major climatic events in Holocene.

关键词： 1.C, 21.Pb and 1.0}Cs, chronology, lacustrine sediments, climatic event, Co Ngoin, central Tibetan Plateau.

Boron isotopic fractionation in laboratory inorganic carbonate precipitation:Evidence for the incorpora-tion of B(OH)_3.into carbonate

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Science china Earth Sciences 2008年第12期51卷 1776-1785页

作者： XIAO YingKai1.2, LI HuaLing1.3. LIU WeiGuo4, WANG XiuFang1.& JIANG ShaoYong5 1.Qinghai {1. of {1. lakes, Chinese Academy of Sciences,{3., china 2 State Key Laboratory of Environmental Geochemistry, {1. of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, china 3.Nanjing {1. of Geology and Mineral Resources, Nanjing 21.01., china 4 State Key Laboratory of Loess and Quaternary Geology, {1. of Earth Environment, Chinese Academy of Sciences, Xi’an 71.075, china 5 State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 21.093. china 1. Qinghai institute of {1. lakes Chinese Academy of Sciences Xining 810008 China 2. State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China 3. Nanjing {1. of Geology and Mineral Resources 210016 Nanjing China 4. State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 5. State Key Laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing 210093 China

A laboratory inorganic carbonate precipitation experiment at high pH of 8.96 to 9.3. was conducted, and the boron isotopic fractionations of the precipitated carbonate were measured. The data show that boron isotopic fractionation factors (αcarb-3. between carbonate and B(OH)3.in seawater range 0.93. and 0.965, with an average value of 0.953. Our results together with those reported by Sanyal and collabo-rators show that the αcarb-3.values between carbonate and B(OH)3.in solution are not constant but are negatively correlated with the pH of seawater. The measured boron isotopic compositions of carbonate precipitation (δ1.Bcarb) do not exactly lie on the best-fit theoretical δ 1.B4-pH curves and neither do they exactly parallel any theoretical δ 1.B4-pH curves. Therefore, it is reasonable to argue that a changeable proportion of B(OH)3.with pH of seawater should also be incorporated into carbonate except for the dominant incorporation of B(OH)4- in carbonate . Hence, in the reconstruction of the paleo-pH of sea-water from boron isotopes in marine biogenic carbonates, the use of theoretical boron isotopic frac-tionation factor (α4-3. between B(OH)4- and B(OH)3.is not suitable. Instead, an empirical equation should be established.

关键词： boron isotopic fractionation biogenic carbonate B(OH)3 incorporation