检索结果-南通市图书馆

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

引用

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 Salt Lakes,chinese academy of sciences,Xining 810008,{2. 2. State key {2. of Loess and Quaternary geology,Institute of Earth {4.,chinese academy of sciences,Xi’an 710075,{2. 1. Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining 810008 China 2. State key laboratory of Loess and Quaternary {2. 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^(11)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 0.982. at pH 7.60 to 1.0178 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 ^(11)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.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Enrichment mechanisms of rare earth elements in marine hydrogenic ferromanganese crusts

引用

Science china Earth sciences 2011年第2期54卷 197-203页

作者： JIANG XueJun1,2.LIN XueHui1,2.YAO De3,4.& GUO WeiDong5 1 key laboratory of {2. Oil and Gas Resources and {2. environment,Ministry of Land and Resources,Qingdao 2.6071,{4. 2.Qingdao Institute of {2. geology,{4. Geological Survey,Qingdao 2.6071,{4. 3 Institute of Resources and environment,Shandong University of Technology,Zibo 2.504.,{4. 4.Institute of Oceanology,{12.,Qingdao 2.6071,{4. 5 Department of Oceanography,Xiamen University,Xiamen 361005,{4. 1. key laboratory of {2. Oil and Gas Resources and {2. {4. Ministry of Land and Resources Qingdao 266071 China2. Qingdao Institute of Marine Geology China Geological Survey Qingdao 266071 China3. Institute of Resources and Environment Shandong University of Technology Zibo 255049 China4. Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China5. Department of Oceanography Xiamen University Xiamen 361005 China

A series of selective extraction experiments were conducted on marine hydrogenic ferromanganese crusts from the seamount near the Line Island to investigate the distribution of rare earth elements （REEs） and the mechanisms of combination between REEs and the hydrogenic ferromanganese crusts. The enrichment of REEs in hydrogenic ferromanganese crusts is attributed mainly to the mineral or oxide/hydroxide of the crust rather than the growth environment. The REEs are present mainly in amorphous ferric oxide/hydroxide rather than in 6-MnO2. Amorphous ferric oxide/hydroxide preferentially combines free REE3＋, while 6-MnO2.combines the REE-carbonate complexes in modern seawater. The REEs in seawater are combined more strongly with amorphous ferric oxide/hydroxides than with 6-MnO2. The positive Ce anomaly in hydrogenic ferromanganese crusts results from the oxidation of soluble Ce3＋ to insoluble Ce4. by the actively soluble oxygen of the bottom current rather than by the oxidation of δ-MnO2.

关键词： rare earth elements hydrogenic ferromanganese crust selective extraction experiment geochemistry combinationmechanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Characterization of MASDs of surface soils in north china and its influence on estimating dust emission

引用

chinese Science Bulletin 2004年第20期49卷 2169-2176页

作者： MEI Fanmin1,2. zhang Xiaoye1, LU Huayu1, SHEN Zhenxing1 & WANG Yaqiang1 1. State key {2. of Loess and Quaternary {4., Institute of Earth environment, {4., Xian 710075, china 2. Xian University of Engineering Science and Technology, Xian 71004., china State key laboratory of Loess and Quaternary {2. Institute of Earth Environment Chinese Academy of Sciences Xi''an 710075 China Xi''an University of Engineering Science and Technology Xi''an 710048 China

The micro-aggregated size distribution (MASD) of surface soil is an important parameter for modelling dust emission. However, there is no dataset of MASDs of all sur-face soil types in north china. The MASDs are here pre-sented, measured by dry sieving, for typical surface soil sam-ples, including sandy soil, gravelly sand soil, gravelly loam soil, loam soil and silt loam soil, collected from sandy deserts, Gobi deserts, oases, farmlands in steppe regions and steppe areas in north china. The MASDs of various surface soil types exhibit a combination of several log-normal distribu-tions of five separated sizes with mean mass median diame-ters (MMDs) of 90, 2.0, 390, 600 and 980 mm, respectively, and mean standard deviations (SDs) of 1.2., 1.4., 1.2., 1.35 and 1.2. respectively. The log-normal distributions corre-spond to very fine sand, fine sand, medium sand, coarse sand and very coarse sand population. On the basis of characteri-zation of the retrieved MASDs of various surface soil types in north china, dust emission fluxes are modelled by a dust production model (DPM model). It is shown that dust emis-sion has been significantly influenced by MASDs. Fine sand and very fine sand are always associated with the highest dust emission fluxes. Emission fluxes of the medium sand, gravelly sand soil, gravelly loam soil and loam soil are lower than those of very fine sand and fine sand, but larger than those of the coarse sand. The differences in dust emission fluxes vary among the different soil types from 101 to 103 mg·m-2.s-1. Dust emission fluxes from sandy deserts and farmlands covered with sand sheets in north china rang from 101 to 104.mg·m-2.s-1 while those from Gobi deserts, farmlands and steppes with gravelly desertification range from 101 to 102.mg·m-2. s-1. The modelled results indicate that deserts and farmlands with sand are the major dust sources in north china.

关键词：华北地区 MASDs 微块状粒度分布地面土壤粉尘排放壤土大气污染气溶胶

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A zooarchaeological study of bone assemblages from the Ma'anshan Paleolithic site

引用

Science china Earth sciences 2010年第3期53卷 395-402页

作者： zhang Yue1,2.3, WANG ChunXue1,2. zhang ShuangQuan1,{2. GAO Xing1,2.1 Institute of Vertebrate Paleontology and Paleoanthropology, {2., Beijing 10004. 2.Joint laboratory of Human Evolution and Archaeometry, {2., Beijing 10004. 3 State key laboratory of Palaeobiology and Stratigraphy, Nanjing 2.0008 1. Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China2. Joint Laboratory of Human Evolution and Archaeometry Chinese Academy of Sciences Beijing 100044 China3. State Key Laboratory of Palaeobiology and Stratigraphy Nanjing 210008 China

Ten thousands of bone fragments were recovered from the Ma’anshan Paleolithic site, of which 4.58 pieces can be identified to skeletal elements or species. In this research, the bone assemblages are quantified based on elements of MNI, MNE, and MAU. Then bone surface modifications and skeletal element profiles of the bone assemblages are studied to understand shlepping behaviors and reveal the technique of disarticulating and defleshing the animals’ bodies, etc. Based on the analyses of bone assemblages and the comparative study with the ethnoarchaeological as well as experimental data, it is assumed that later hominids at the site made fuller use of the game animals than the earlier hominids. Incorporating the lines of evidence from chronological dating, paleoenvironment, and polished bone tools between the two cultural layers, here we propose three hypotheses suggesting that the changes of environment, the migrations of the hominids from the North, or the demographic pulses may cause such a behavioral difference. However, it is yet to be determined which hypothesis can better explain the changes.

关键词： Ma’anshan site zooarchaeology Paleolithic hominid behavior

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Constraints of authigenic carbonates on trace elements (Sr,Mg) of lacustrine ostracod shells in paleoenviron-ment reconstruction and its mechanism

引用

Science china Earth sciences 2008年第5期51卷 654-664页

作者： HU Guang1,2. JIN zhangDong1 & zhang Fei3 1 State {2. {4. of Loess and Quaternary geology, Institute of Earth {4., chinese academy of sciences, Xi’an 710075, china 2.Graduate University of the chinese academy of sciences, Beijing 10004., china 3 College of Resources and {4.al Science, Nanjing Agricultural University, Nanjing 2.0095, china State key laboratory of Loess and Quaternary {2. Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China Graduate University of the chinese academy of sciences Beijing 100049 China College of Resources and Env

Molar ratios of Mg/Ca and Sr/Ca were measured in two species of ostracod shells preserved in the upper core (15–55 m) of the Hequing Basin in Yunnan Province, southwest china. By correlating the molar ratios between Mg/Ca and Sr/Ca and comparing them with Sr concentrations of the sediments, we suggested that: (1) the molar Mg/Ca and Sr/Ca ratio variations in respective ostracod primo reflected the changes in its ambient water composition and ecology; (2. the molar Sr/Ca ratios responded better to the salinity change linearly than Mg/Ca without aragonite precipitation in the system, and otherwise there was no linear relation between them; and (3) the molar Sr/Ca ratios were mainly controlled by salinity and authigenic carbonate precipitation, whereas the molar Mg/Ca ratios were related to both salinity and temperature. In fact, the rate of ostracod growth owing to temperature controls the fluctuation of Mg/Ca in shells. Here, more attentions should be paid to the constraint of authigenic mineral precipitation processes on the trace elements in ostracod shells and to the correlation between these trace elements in biogenic carbonates and compositions of the sediments in systems and in future in vitro experiments.

关键词： ostracod shell molar Sr/Ca ratio molar Mg/Ca ratio environmental response Heqing Basin

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Carbon isotope composition of the Lower Triassic marine carbonates, Lower Yangtze Region, South china

引用

Science china Earth sciences 2006年第3期49卷 225-241页

作者： ZUO Jingxun1,2. TONG Jinnan3, QIU Haiou4.& ZHAO Laishi3 1. Nanjing Institute of geology and Palaeontology, chinese academy of sciences, Nanjing 2.0008, {2. 2. Henan Institute of Geological Survey, Zhengzhou 4.0007, {2. 3. State key {4. of Geological Processes and Mineral Resources at {2. University of Geosciences, Wuhan 4.0074. {2. 4. Faculty of Material sciences and Chemical Engineering, {2. University of Geosciences, Wuhan 4.0074. {2. 1. Nanjing Institute of geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China 2. Henan Institute of Geological Survey Zhengzhou 450007 China 3. State key laboratory of Geological Processes and Mineral Resources at {2. University of Geo{2. Wuhan 430074 China 4. Faculty of Material sciences and Chemical Engineering China University of Geosciences Wuhan 430074 China

Studies on three Lower Triassic sections located on the shallow water platform, the deep water slope and in the deep water basin in the Lower Yangtze Region, South china, show the similar trend of carbon isotope evolution. Biostratigraphic correlations among the Lower Triassic sections on the basis of standard conodont zones indicate that three negative shifts occurred in the Griesbachian, the Smithian and the late Spathian stages respectively, and one distinctly positive shift occurred in the early Spathian stage. Trend of carbon isotope evolution of the Lower Triassic reflects some significant changes in the global carbon cycle. Moreover, δ 13C background values are intensively controlled by palaeogeographic environment. In general, δ 13C values from deep-water slope carbonates are lighter than those from carbonate platform and heavier than those from deep-water basin carbonates. The positive carbon isotope excursion may be induced by a significant amount of organic carbon burial in {2. sediments and increase in primary productivity. The large negative carbon isotope excursions during the Early Triassic in Lower Yangtze Region are interpreted to relate to volcano eruptions based on tuffaceous claystone interlayers observed near the Permian-Triassic boundary, the Induan- Olenekian boundary and the Lower Triassic-Middle Triassic boundary.

关键词： Lower Triassic, carbon isotope compositions, palaeogeography, volcanic eruptions, Lower Yangtze Region.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling the impact of Australian Plate drift on Southern Hemisphere climate and environment

引用

chinese Science Bulletin 2005年第14期50卷 1495-1502页

作者： ZHOU Botao1,5, ZHAO Ping2. JIAN Zhimin3 & HE Jinhai4.1. Nansen-Zhu International Research Center, Institute of Atmospheric Physics, chinese academy of sciences, Beijing 10002., china 2. Institute of Climate and {2., chinese {4. of Meteoro- logical sciences, Beijing 100081, china 3. laboratory of marine geology, Tongji University, Shanghai 2.0092. china 4. Department of Atmospheric sciences, Nanjing Institute of Meteorol- ogy, Nanjing 2.004., china 5. Graduate School of the chinese academy of sciences, Beijing 100039, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of the chinese academy of sciences Beijing 100039 China Institute of Climate and environment Chinese Academy of Meteorological Sciences Beijing 100081 China laboratory of marine {2. Tongji University Shanghai 200092 China Department of Atmospheric sciences Nanjing Institute of Meteorology Nanjing 210044 China

Using a global atmosphere-ocean coupled model with the present-day and 14.MaB.P. oceanic topogra- phy respectively, two experiments are implemented to inves- tigate the effect of different locations of Australian Plate on the atmospheric circulation in middle-high latitudes of the Southern Hemisphere. The results show that when Austra- lian Plate lay south at 14.MaB.P., both anticyclone circula- tions in the subtropical oceans and cyclone circulation around 60°-70°S are strengthened. Subtropical highs and circumpolar low pressure appear stronger, which results in much stronger Antarctic Oscillation and shorter period of Antarctic Oscillation Index (AOI) at 14.MaB.P. The rainfall and the surface air temperature also change correspondingly. The precipitation decreases around 4.°S and increases around 60°-70°S, and the surface air temperature rises in high latitudes of the South Pacific and descends over the Weddell Sea and its north side. Besides, due to the changes of the temperatures and winds, Antarctic sea ice coverage also changes with its increasing in the Ross Sea and its west re- gions and decreasing in the Weddell Sea.

关键词：半球气候地球环球澳大利亚漂流物海洋地形学

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Distribution characteristics of magnetic susceptibility of the surface sediments in the southern Yellow Sea

引用

chinese Science Bulletin 2003年第B06期48卷 37-41页

作者： GE Shulan~(1,2.3), SHI Xuefa~1 & HAN Yibing~1 1. key laboratory of {2. Sedimentology and {4.al geology, First Institute of Oceanography, State Oceanic Administration. Qingdao 2.6061. {4. 2. Institute of geology and Geophysics, chinese academy of sciences, Beijing 10002.. {4. 3. Graduate School. chinese academy of sciences, Beijing 100039. {4. 1. key laboratory of {2. Sedimentology and {2.al {4. First Institute of Oceanography State Oceanic Administration 266061 Qingdao China 2. Institute of geology and Geophysics Chinese Academy of Sciences 100029 Beijing China 3. Graduate School Chinese Academy of Sciences 100039 Beijing China

The characteristic distributions of magnetic susceptibility (MS) are analyzed on the basis of susceptibility of 172.surface sediment samples in the southern Yellow Sea (SYS). The preliminary results are as follows: first, the distributions clearly correspond to different modern sediment assemblages in the continental sea, which indicates different sediment origins. With the 30 μCGS isoline being taken as demarcation line, the study area can then be divided into section H (high MS value area) and section L (low MS value area). Section H is mainly adjacent to land with two main sources of the Changjiang River and the Huanghe *** L is mainly an eddy sediment area, where Yellow Sea Cold Water is entrenched all the year round. The distribution pattern of MS could tell apart strong or weak hydrodynamic conditions and has a close relation to the circulation system in this area. At the areas of the SYS Circumfluent and northern East china Sea (NECS) Circumfluent (weak hydrodynamic), the MS has low values, while in the areas of Coastal Current (strong hydrodynamic), the values are *** the same time, the oxidizing areas tend to take on higher MS, while the reducing areas have lower one. It seems safe to say that the MS in the continental sea reflects more of the sediment origin and sedimentary environment, which is different from that of loess, lake and surface soil as a climate proxy.

关键词：中国黄海表面沉积物磁化率等值线长江黄河旋涡沉积区循环系统

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The crustal structure under Sanjiang and its dynamic implications:Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

引用

Science china Earth sciences 2005年第9期48卷 1329-1336页

作者： zhang Zhongjie1, BAI Zhiming1, WANG Chunyong2. TENG Jiwen1, Lü Qingtian3, LI Jiliang1, LIU Yifeng1 & LIU Zhenkuan4.1. Institute of geology and Geophysics, {2., Beijing 10002., china 2. Institute of Geophysics, china Seismological Bureau, Beijing 100085, china 3. Institute of Deposition Resource, chinese academy of Geosciences, Beijing 100037, china 4. School of Exploration and Information, china University of Geosciences, Beijing 100083, china 1. Institute of geology and Geophysics Chinese Academy of Sciences 100029 Beijing China 2. Institute of Geophysics China Seismological Bureau 100085 Beijing China 3. Institute of Deposition Resource Chinese Academy of Geosciences 100037 Beijing China 4. School of Exploration and Information China University of Geosciences 100083 Beijing China

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, china. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we recon- struct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflec- tion structure along the profile can be divided into 3 segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1―0.2.km/s slower and seismic reflection am- plitudes from Moho discontinuity are stronger than the other 2.segments. In the studied area, crustal thickness is about 4. km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8―10 km, along the segment of 80―115 km of the profile (south- ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural environment of earthquake development and the contact rela- tionship between the Tengchong block, Banshan block and Luxi trough.

关键词： Sanjiang area wide-angle seismic profile crustal structure.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mineral provinces and material provenance of the surficial sediments near the Zhongsha Islands in the South china Sea

引用

Acta Oceanologica Sinica 2007年第1期26卷 66-76页

作者： YAN Quanshu1, 2. 3, SHI Xuefa2., WANG Kunshan2.. Institute of Oceanology, chinese academy of sciences, Qingdao 2.6071, china2. {2. {2. of marine Sedimentology and {4. geology of State Oceanic Administration, First Institute of Oceanograghy, State Oceanic Administration, Qingdao 2.6061, china3. Graduate School, chinese academy of sciences, Beijing 10004., china Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China

Characteristics and distribution patterns of clastic minerals (0.063～0.12. mm) in bottom sediments represent a significant indicator for the identification of the origin of sediment. One hundred and fourteen surface sediment samples, which were collected from the area near the Zhongsha Islands in the South china Sea, were analysed to identify the mineral suites and their distributions in the study area. The area can be divided into three mineral provinces: (Ⅰ) a province of biogenic minerals, which mainly originate from the Zhongsha Atoll; (Ⅱ) a province of volcanogenic minerals, which are mainly derived from local basaltic seamounts and small-scale volcanoes that are probably erupting, with some influences from the island-arc volcanic region around the South china Sea; and (Ⅲ) a mixed mineral province whose material source includes biogenic minerals, volcanogenic minerals and terrigenous minerals; the last province can be subdivided into a mixed mineral sub-province of the northeastern part of the study area, in which terrigenous minerals are mainly derived from china’s Mainland and do not exceed 17°N, and a mixed mineral sub-province of the southeastern part of the study area, in which terrigenous minerals are derived from Kalimantan and Indochina Peninsula and might be further transported into the deep sea basin through sub{4. canyons.

关键词： South china Sea Zhongsha Islands light mineral minerals province material provenance

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：