The evolution characteristics and fractionation mechanism of carbon isotopes in the process of “multi-stage hydrocarbon generation”     

徐永昌刘文汇  沈平张晓宝  黄第番宋一涛 《中国地球化学学报》2005,24(1):1-8

The Jiyang Sag and the Liaohe Basin are the two important areas where immature oil resources are distributed in China. From these two areas immature-low mature to mature oil samples were collected for carbon isotopic analysis. The extracts of source rocks are dominant in the Jiyang Sag while crude oils are dominant in the Liaohe Basin. The maturity index, Ro, for source rocks varies from 0.25%(immature) to 0.65% (mature). Studies have shown that within this range of Ro values the extracts of source rocks and crude oils, as well as their fraction components, have experienced observable carbon isotope fractionation. The carbon isotopic values tend to increase with burial depth, the oils become from immature-low mature to mature, and the rules of evolution of oils show a three-stage evolution pattern, i. e. ,light→heavy→light→heavy oils. Such variation trend seems to be related to the occurrence of two hydrocarbon-generating processes and the main hydrocarbon-forming materials being correspondingly non-hydrocarbons and possessing MAB characteristics, lower thermodynamic effects and other factors. In the process towards the mature stage, with increasing thermodynamic effects, the thermal degradation of kerogens into oil has become the leading factor, and correspondingly the bond-breaking ratio of ^12C-^13C also increases,making the relatively ^12C-rich materials at the low mature stage evolve again towards ^13C enrichment.  相似文献   

中国大陆部分构造单元出露地壳与全球大陆上地壳化学成分的比较——对地壳演化的制约和思考     

汪洋 《地质通报》2005,(Z1)

根据中国东部上地壳区域元素丰度研究和新疆北部地区1∶20万化探成果,总结了23个二级大地构造单元出露地壳的元素地球化学特征。与全球大陆上地壳元素丰度值的对比显示,中国大陆出露地壳成分演化程度介于岛弧与成熟的加拿大地盾之间。华北、扬子地台由于含大量碳酸盐岩地层,其出露地壳SiO2含量偏低,明显富集CaO和MgO,可见在出露地壳和上地壳元素丰度值研究中不应忽视碳酸盐岩的贡献。相对于最新发表的2种全球大陆上地壳平均成分模型,中国大陆出露地壳系统亏损Au、Hg、Mo、Sn和W,表明现有上地壳模型过高地估计了Au、Hg、Mo、Sn、W等元素丰度值。华北地台及其南缘的秦岭-大别山造山带出露地壳具低μ(238U/204Pb)值(<8)特征,但其他地区μ值较高,暗示华北地台及其周边地区出露地壳的低μ值特点不具备全球意义。鉴于中国大陆内部各构造单元之间出露地壳成分的显著横向差异,以华北地台为主体的上地壳成分模型目前尚无充分理由作为中国和全球大陆上地壳平均值的可靠代表。  相似文献   

豫西小秦岭地区太华杂岩中花岗质片麻岩的 元素地球化学及其构造意义          下载免费PDF全文

Zhou Hanwen 《地球科学》1998,23(2):88

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Organic/ Inorganic Occurrence of Metallic Elements of the Black Shale-Hosted Baiguoyuan Silver-Vanadium Deposit in Xingshan, Hubei     

ZHUANG Hanping  LU Jialan  FU Jiamo  LIU Jinzhong Guangzhou Institute of Geochemistry  Chinese Academy of Sciences  Guangzhou REN Chigang  ZOU Degang The nd Department of Physics  Fudan University  Shanghai  TIAN Weizhi Chinese Academy of Atomic Science  Beijing 《《地质学报》英文版》1998,72(3):299-307

By means of kerogen purification, the proton induced X-ray emission (PIXE) and instrumental neutron activation analysis (INAA), the authors have studied the organic/inorganic occurrence modes of the metallic elements of the Baiguoyuan silver-vanadium deposit hosted in black shale in Hubei Province, China. The result shows that Au, Hg and Ta have a strong tendency to occur organically, with more than 70% of these elements being associated organically. Se, Ga, Ag and Hf are partly associated with organic matter, with more than 20% of them occurring organically. Compared with the above elements, Zn, Cu, As and Sb are weakly associated organically, and tend to be enriched in kerogen. However, Mn, Th, U, V, Co, Cr, Al, Fe and Sc usually occur inorganically. Of the rare earth elements (REE), La, Ce, Tb, Dy, Yb and Lu have stronger ability to be associated with organic matter than Sm and Eu.  相似文献   

Selenium Enrichment in Cambrian Stratabound Gold Deposits in the Western Qinling Mountains   总被引：1，自引：0，他引：1  

Liu Jiajun  Open Laboratory of Ore Deposit Geochemistry  Institute of Geochemistry  Chinese Academy of Sciences  Guiyang  Guizhou Zheng Minghu  Chengdu Institute of Technology  Chengdu  Sichuan Liu Jianming  Research Centre of Mineral Resources Exploration  Chinese Academy of Sciences  Beijing Zhou Yufeng  Gu Xuexiang  Zhang Bin  Lin Li  Chengdu Institute of Technology  Chengdu  Sichuan  Lu Wenquan Institute of Comprehensive Utilization of Mineral Resources  Chengdu  Sichuan 《《地质学报》英文版》1997,71(4):423-432

Stratabound gold deposits in the western Qinling Mountains occur in Cambrian chert formation composed of carbonaceous chert and carbonaceous slate. The distinctive chert formation provides important grounds for the mineralization and controls on the formation of gold deposits. Study shows that Se is exceptionally higher in both host rocks and gold orebodies. It may be recovered as a valuable component in ores for total utilization, and in some localities even independent Se orebodies (which are mined exclusively for Se) may be delineated. In gold ore Se mainly occurs as independent minerals or in the isomorphous form in sulphides and there is a positive correlation between Se and Au.  相似文献   

Subsolidus Phase Relations in the System MgO-SiO_2-Cr-O and Thermodynamic Properties of Related Cr~(2+)-Containing End-members     

H.St.CO'' Neill  F.Seifert 《《地质学报》英文版》1996,70(4):420-434

Subsolidus phase relations have been determined in the systems SiO2-Cr-O and MgO-SiO2-Cr-O in equilibrium with metallic Cr, at 1100 to 1500℃ and 0 to 2.88 GPa. The results show that there are no ternary phases in the SiO2-Cr-O system at these conditions, i.e., only the assemblage eskolaite-Cr-metal-quartz (or tridymite) is found. In the MgO-containing system, however, extensive substitution of Cr2+ for Mg is observed in (Mg, Cr2+)2SiO4 olivine, (Mg, Cr2+)2Si2O6 pyroxene, and (Mg, Cr2+)Cr2O4 spinel. Cr3+ levels in olivine and pyroxene are below detection limits. The pyroxene is orthohombic at XCrPx2+ < 0.2, monoclinic at higher XCrPx2+ . Thestructure of the spinels becomes tetragonally distorted at XCr2+Sp >0.2. The experimental datahave been fitted to a thermodynamic model, and the authors obtained the mixing parameter (W) of Mg-Cr2+ in olivine, pyroxene and spinel, and the relation between temperatures and free energies of formation for the end-members: Cr2+-olivine (Cr2SiO4), Cr2+-pyroxene (Cr2Si2O6)  相似文献   

湖南砂矿金刚石的颜色   总被引：4，自引：0，他引：4  

郭九皋  陈丰  邓华兴  谈逸梅  容振球  邓尔森 《矿物学报》1986,(2)

研究表明,湖南砂矿金刚石中存在着两类决定金刚石颜色(主要指黄、褐和绿色)的色心。一类是氮原子中心,有孤氮原子和N3中心。另一类是辐射损伤中心,有GR1、637、595、H3、H4和3H中心。文中还讨论了这些色心的地质意义。  相似文献   

湖南砂矿金刚石中顺磁氮的分配特点和金刚石归类问题   总被引：2，自引：1，他引：2  

蔡秀成  郭九皋  陈丰  富毓德  唐荣炳  谈逸梅  邓尔森 《矿物学报》1986,(3)

利用EPR检测了200多颗湖南砂矿金刚石。为53颗晶体测定了顺磁N的含量。阐明了砂矿金刚石中顺磁N分配的一般特点:具顺磁N信号者占30％,具较大顺磁N含量(10~(17)—10~(18)N原子/cm~3)者只占7％,属I_b型的晶体～2％。通过顺磋和红外光谱资料对比,发现了一些奇异现象,设想后者起因于混型晶的存在。为使金刚石正确归类,给出了一套测试方案,强调了紫外、红外光谱,紫外形貌照相和EPR等手段的联合使用。  相似文献   

稀土磷酸盐矿物合成的一些实验     

黄舜华  王中刚  章钟嵋  何松裕 《矿物学报》1987,(2)

本文研究了稀土磷酸盐类矿物的形成条件及矿物中各稀土元素相互置换的可能性和物理化学条件。 实验表明,独居石的形成条件范围很宽,它可在压力70—1000bar、温度>130℃、pH=2—10的范围内形成。磷钇矿的形成条件与独居石相似。在不同的温、压及pH条件下,从La—Tb的磷酸盐呈独居石的结构,而Tb—Lu却突变为磷钇矿的结构。  相似文献   

AgS_2-Cu_2S-PbS-Bi_2S_3四元体系相关系研究(Ⅱ):铜银铅铋硫盐矿物结晶化学及分类     

吴大清 《矿物学报》1987,(3)

对Ag_2S-Cu_2S-PbS-Bi_2S_3四元体系内铋硫盐矿物的类质同象取代类型的研究表明,它共有四种:配对取代Ag(Cu)+Bi=2Pb,简单取代Ag=Cu,Bi(Pb)=Cu和Cu原子填隙(以平衡Bi或Pb为Cu取代时电价差)。研究还给出了体系内10个重要固溶体的成分及结晶参数之间的关系。对这些固溶体及铜、银、铅铋硫盐矿物结构特征、共生和共生长关系研究表明,它们可以分成四个系列:块硫铋银矿、硫铋铅矿、辉铋矿-针硫铋铅矿、贺硫铋铜矿。  相似文献