检索结果-南通市图书馆

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

引用

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 Institute of salt Lakes, chinese academy of sciences, Xining 810008,{2. 2.state key laboratory of Environmental geochemistry, Institute of geochemistry, chinese academy of sciences, Guiyang 550002.{2. 3 Nanjing Institute of geology and Mineral Resources, Nanjing 2.0016,{2. 4 state key laboratory of Loess and Quaternary geology, Institute of Earth Environment, chinese academy of sciences, Xi’an 710075,{2. 5 state key laboratory for Mineral Deposits Research, Department of Earth sciences, Nanjing University, Nanjing 2.0093,{2. 1. Qinghai Institute of salt Lakes Chinese Academy of Sciences Xining 810008 China 2. state key laboratory of Environmental {2. Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China 3. Nanjing Institute of geology and Mineral Resources 210016 Nanjing China 4. state key laboratory of Loess and Quaternary {2. 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 9.34 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 0.937 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 (δ11Bcarb) do not exactly lie on the best-fit theoretical δ 11B4-pH curves and neither do they exactly parallel any theoretical δ 11B4-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

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

Jinning granodiorite and diorite deeply concealed in the central Tarim Basin

引用

science china Earth sciences 2005年第12期48卷 2061-2068页

作者： LI Yuejun1, 2. sONG Wenjie2. WU Genyao1, WANG Yifen1, LI Yuping2.& ZHENG Duoming2.1. Institute of geology & geophysics, {2. academy of sciences, Beijing 10002., china 2. Tarim Oil-field Company, Petrochina, Korla 841000, china 1. Institute of geology & geophysics Chinese Academy of Sciences 100029 Beijing China 2. Tarim Oil-field Company 841000 Korla PetroChina China

The 72.0-m-deep Well Tacan 1 in the central Tarim Basin is the deepest in china. Purplish gray medium-grained granodiorite containing dark gray fine-grained diorite xenolith is revealed at the base of the well (7169―72.0 m), and they are results of the Jinning magmatic activities. Trace-element geochemistry and REE profiles of both rock types are similar, indicating that they are calc-alkaline series I-type granitoid. Proxies of diorite signify the development of a magmatic arc due to subduction at ca. 12.0 Ma. The granodiorite was formed before 890―932.Ma. However, more study is needed to clarify if the arc diorite represents a ca. 300 Ma extension of the subduction or a reactivation during the orogenic collision event at ca. 900 Ma.

关键词： diorite, granodiorite, magmatic arc, Jinning orogeny, Tarim 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

A restudy of Oryctocephalus indicus (Reed,1910)

引用

Progress in Natural science:Materials International 2006年第11期16卷 1177-1182页

作者： ZHAO Yuanlong~1**, YUAN Jinliang~2. PENG shanchi~ 2.3 , YANG Xinglian~1, PENG Jin~1, LIN Jihpai~4, and GUO Qingjun~5(1. College of Resource and Environment of Guizhou University, Guiyang 550003, china 2. Nanjing Institute of geology and Palaeontology, {2. academy of sciences, Nanjing 2.0008, china 3. state key laboratory of Papaeobiology and stratigraphy, Nanjing Institute of geology and Palaeontology, Nanjing 2.0008, china 4. Department of Geological science, Ohio state University, Columbus, OH 432.0, UsA 5. Institute of geochemistry, {2. academy of sciences, Guiyang 550002. china) College of Resource and Environment of Guizhou University Guiyang 550003 China Nanjing Institute of geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China state key laboratory of Papaeobiology and stratigraphy Nanjing Institute of Geology and Palaeontology Nanjing 210008 China Department of Geological science Ohio State University Columbus OH 43210 United States Institute of geochemistry Chinese Academy of Sciences Guiyang 550002 China

Restudy on morphology of Oryctocephalus indicus (Reed, 1910), based on specimens from Guizhou, china and Nevada UsA, suggests that the subspecies regarded previously as Oryctocephalus indicus indicus (Reed, 1910), O. indicus latus Zhao et Yuan 2.02. and O. indicus kobayashi saito, 1934, are synonymous, and Oryctocephalus americanus sundberg et McCollum, 2.03 is a similar form of O. indicus. Oryctocephalus indicus is rediagnosed as having a glabella that is subconical in outline and tapering forward slightly; a thorax that comprises 12.segments, and a small pygidium that bears 2.3 axial rings with a terminal piece and a postaxial ridge. Oryctocephalus indicus is widely distributed in eastern Guizhou and ranges through a great interval of Kaili Formation. Its first appearance is almost identical with these events of trilobite extinction-recovery occurring at the end of the Early Cambrian, the alternation of acritach assemblages, the change of trace elements (REE) and stable isotopes (carbon) at the Wuliu-Zengjiaya section. As one of the key forms for defining the traditional Lower-Middle Cambrian boundary (the base of Cambrian series 3 and stage 5 in the new Cambrian chronstratigraphic standard), O. indicus has received detailed study and has more advantages than other species such as Ovatoryctocara granulata Tchernysheva, 1962.or Arthricocephalus chauveaui Bergeron, 1899.

关键词： Oryctocephalus indicus restudy Kaili Formation Cambrian Guizhou china.

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

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 Marine sedimentology and Environmental {2., First Institute of Oceanography, state Oceanic Administration. Qingdao 2.6061. china 2. Institute of {2. and geophysics, chinese academy of sciences, Beijing 10002.. china 3. Graduate school. chinese academy of sciences, Beijing 100039. china 1. key laboratory of Marine sedimentology and Environmental {2. 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

Kinetics of petroleum generation determined from multiple cold trap pyrolysis gas chromatography

引用

chinese science Bulletin 1997年第3期42卷 254-258页

作者： LIU Jinzhong and TANG Yongchun1. state key laboratory of Organic {2., Guangzhou Institute of {2., chinese academy of science Guangzhou 510640, china 2. Chevron Petroleum Technology Company, La Habra, CA 90633-0446, UsA state key laboratory of Organic {2. Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Chevron Petroleum Technology Company La Habra USA

THOUGH commercial Pyrolysis-GC is widely used to evaluate petroleum source rocks, its chromatogram composed of all compounds generated in the whole pyrolysis process cannot provide generating rates or activation energy distributions of individual component or compound groups. To overcome the limitation, a new technique, multi cold trap pyrolysis gas chromatography (MCTP-GC), has been developed by Chevron Petroleum Technology Compa-

关键词： organic geochemistry pyrolysis kinetics.

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

Progress and review of the studies on the end-Triassic mass extinction event

引用

science china Earth sciences 2005年第12期48卷 2049-2060页

作者： DENG shenghui1,2. LU Yuanzheng1,2.3 & XU Daoyi4 1. Research Institute of Petroleum Exploration and Development, Beijing 100083, china 2. key {2. of Oil and gas Reservoir of Petrochina, Beijing 100083, china 3. china University of Geosciences, Beijing 100083, china 4. Institute of geology, china Earthquake Administration, Beijing 10002., china 1. Research Institute of Petroleum Exploration and Development 100083 Beijing China 2. key laboratory of Oil and {2. Reservoir of Petrochina 100083 Beijing China 3. china University of Geosciences 100083 Beijing China 4. Institute of geology China Earthquake Administration 100029 Beijing China

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic. However,it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recog-nized yet. The extinction event is strongly marked at specific level but shown a complicated situa-tion at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption. The Triassic-Jurassic (Tr-J) boundary mass extinction event is still poorly understood because no enough data have been obtained from the Tr-J boundary successional sections of both marine and terrestrial sediments, and most of these studies were regionally restricted. The basic aspects of the event and its associated environmental conditions remain poorly characterized and the causal mechanism or mechanisms are equivocal. some authors even doubt its occurrence. china has many successionally developed terrestrial and marine Tr-J sections. Detailed studies of these sections may be important and significant for well understanding of the event.

关键词： progress, review, end-Triassic, mass extinction, mechanism, Tr-J boundary.

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 mechanism of gold during the process of lateritization in southern area of the Yuanmou ancient landmass, Yunnan, china

引用

chinese science Bulletin 1999年第S2期44卷 90-91页

作者： sUN Chengxing~1, WANG shijie~1, DAI Fusheng~2.and LUO Yi~2.1. state key laboratory of Environmental {2., Institute of {2., chinese academy of sciences, Guiyang 550002. china 2. Department of geology, Kunming University of science and Technology, Kunming 650093, china state key laboratory of Environmental {2. Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Department of geology Kunming University of Science and Technology Kunming 650093 China

sINCE the first discovery of lateritic gold deposit which is easier to mining and dressing at Boddington inWestern Australia at the beginning of the 1980s, geologists have paid much attention to it, and it wasfound in tropical and subtropical regions. However, recently the metallogenetic mechanism has notbeen understood very well. In this note we reported some research results on the enrichment mechanism ofgold during the process of lateritization in the case of three lateritic profiles with some degree of gold enrichment located in southern area of the Yuanmou ancient landmass, Yunnan Province. The parent rocks of the investigated profiles （about 5-8 m thick） is metamorphic schist, in whichmean content of gold is 13.3×10sup>-9sup>. samples were collected from two pits at Xujie （Mouding County）and an outcrop of gully at Menglingou （Yuanmou County）, dried in air and ground in agate mortar to

关键词： gold enrichment lateritizafion Yunnan.

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

Chronological record of the Early Mesozoic underplating in the northern margin of North china—U-Pb chronometry of zircons in the Late Mesozoic andesite from Western Liaoning

引用

Progress in Natural science:Materials International 2007年第8期17卷 943-947页

作者： shao ji'an~(1,2.*) Zhang Hongfu~2.Liu Xiaoming~3 Li Zhitong~4 (1.school of Earth and space sciences,Peking University,Beijing 100871,china 2.Institute of geology and {2. and key laboratory of Mineral Resources,chinese academy of sciences,Beijing 10002.,china 3.key laboratory of Continental Dynamics,Northwestern University,Xi'an 710069,china 4.Institute of geology and Mineral Resources of shenyang,shenyang 110032.china) [a]school of Earth and space sciences Peking University Beijing China [b]laboratory of Mineral Resources Chinese Academy of Sciences Institute of Geology and Continental Dynamics Beijing China [c]key laboratory of Continental Dynamics Northwestern university Xi'an China [d]Institute of geology and Mineral Resources of shenyang Shenyang China

Cathodoluminescence spectroscopic analysis of zircons in the uppermost sanukites of the early Cretaceous Yixian Forma- tion in Western Liaoning reveals zoning structures of the zircons in the volcanic rocks. LA-ICP-Ms chronometry shows that the central part of the zircons is remnant zircon with a U-Pb dating of 2.4 Ma,which is consistent with the age of the Early Mesozoic underplating granulites,and that the periphery is zircon crystallizing out of the host magma with a U-Pb dating of 116 Ma,which is highly consistent with the Ar-Ar dating of the host volcanic *** of the clinopyroxenes xenocrystals in the sanukites are similar to those of the clinopyroxenes in the underplating granulites,indicating that the granulites accreted to the lower crust in the Early Mesozoic have been reformed and disrupted by the upwelling diapers of the asthenosphere and taken part in formation of the sanukites in the Late Mesozoic.

关键词： northern margin of North china Mesozoic volcanic rock U-Pb chronometry of zircon underplating granulite

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

Advances in geochemical research on nanometer materials

引用

Progress in Natural science:Materials International 2006年第4期16卷 331-337页

作者： ZHU Xiaoqing and WANG Zhonggang key laboratory of Ore Deposit {2., Institute of {2., chinese academy of sciences, Guiyang 550002. china [a]key laboratory of Ore Deposit {2. Institute of Geochemistry Chinese Academy of Sciences Guiyang China

Important advances have been made in the field of geochemistry since nanometer science and technology were introduced into the field of geoscience. The nanometer particulates have been discovered in naturally-occurring ore deposits, volcano-eruptive materials and geo-gases, and a more detailed exploration of the metallogenic mechanism of endogenic metallic ore deposits has been conducted. It is considered that some ore-forming metals may transport in the form of native particulates. Because they have very strong capabilities of adsorption, adsorption is always regarded as an important mechanism of metallogenesis under supergenic and low temperature conditions. Therefore, a new technology of ore exploration has also been developed. This paper attempts to review the new advances in geochemical research on nanometer materials, as well as its perspectivess.

关键词： nanometer geochemistry adsorption metallogenic theory prospecting method.

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

Helium isotope investigation on magnetic reversal boundaries of loess-paleosol sequence at Luochuan, central chinese Loess Plateau

引用

chinese science Bulletin 2007年第17期52卷 2407-2412页

作者： DU XueQing1,6, WANG YongHong2. REN JianGuo3, YE XianRen4 & LU HuaYu5,1 1 state key laboratory of Loess and Quaternary {2., Institute of Earth Environment, chinese academy of sciences, Xi’an 710075, china 2.College of Marine Geosciences, Ocean University of china, Qingdao 2.6003, china 3 National Natural science Foundation of china, Beijing 100085, china 4 lanzhou Research Center for Petroleum and Natural gas Resources, Institute of {2. and geophysics, chinese academy of sciences, lanzhou 73.000, china 5 key laboratory of Coast and Island Development, school of Geographic and Oceanographic sciences, Nanjing University, Nanjing 2.0093, china 6 Graduate University of chinese academy of sciences, Beijing 100049, china state key laboratory of Loess and Quaternary {2. Institute of Earth Environment Chinese Academy of Sciences Xi''an 710075 China

Extraterrestrial particles have higher 3He/4He ratios than those of terrestrial sediments ( > 100 Ra versus < 0.03 Ra, where Ra is the 3He/4He ratio normalized to the atmospheric value of 1.4×10?6). The inter- planet... 详细信息

Extraterrestrial particles have higher 3He/4He ratios than those of terrestrial sediments ( > 100 Ra versus 3 Ra, where Ra is the 3He/4He ratio normalized to the atmospheric value of 1.4×10?6). The inter- planetary dust particles (IDPs), which are very rich in 3He, continuously bombard the Earth and can accumulate in deposits. IDPs sedimentation rate changes can significantly influence 3He concentration in the Earth surface sediments. since IDPs are not easy to detect in terrestrial deposits, measuring helium isotopes is a helpful approach to examine changes in IDPs. Helium concentration and helium isotopic composition magnetic substances and the quartz particles were examined for helium concen- tration and helium isotopic ratio. Results show that the 3He/4He ratio and the 3He concentrations of the magnetic substances are clearly higher than those of the bulk samples and the quartz particles, and, the 3He/4He ratio of the extracted magnetic substances is also higher than that of the average level of the Earth’s crust. The higher helium content in the magnetic fractions can be explained by an influx of IDPs.

关键词：中国黄土高原古土壤氦同位素行星际尘埃颗粒反方向磁化

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

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：