西太平洋富钴结壳元素组合特征及其地质意义   总被引：10，自引：0，他引：10  

何高文  薛婷  孙晓明  张学华  朱克超  王生伟 《矿物岩石地球化学通报》2005,24(2):125-129

海山富钴结壳是一种重要的海底固体矿产。对西太平洋海山的56个结壳样品进行了23种化学组分分析,并利用R型聚类分析和R型因子分析,分别提取四组元素组合和四个主因子。综合特征表明．富钴结壳在形成过程中,经历了一次强度较大的锰矿物相成矿作用,Co、Ni等元素的富集与此有关;铁矿物相的成矿作用强度较小,但表现出多期次的特点;锰、铁矿物是不同成矿作用的产物;结壳形成过程中,可能遭受了二次磷酸盐化作用,结壳中磷酸盐矿物的形成对铁矿物相的形成可能有抑制作用。  相似文献   

锆基柱撑蒙脱石研究进展     

曾少雁  吴平霄 《矿物岩石地球化学通报》2005,24(2):165-170

锆基柱撑蒙脱石是近年来多孔材料研究的热点之一。由于大的比表面积、层间距以及孔容积,而具有良好的吸附与催化性能。近年来,锆基柱撑蒙脱石的研究进展主要集中在多种复合柱撑蒙脱石的制备,其应用多在有机物、重金属吸附和催化有机反应等方面,而对柱撑机理、层间结构的研究较少,有待深入。  相似文献   

西昆仑甜水海古湖泊介形类及其环境意义   总被引：22，自引：2，他引：20  

李元芳  李炳元  王国  李世杰  朱照宇 《湖泊科学》1997,9(3):223-230

为探讨青藏高原演化过程,在高原西北部甜水海湖盆地区进行了钻探,井深５６．３２ｍ,对所获取的岩芯做了介形类分析,共发现介于形类８属１０种,按照介形类生态及在钻孔中的分布特征,将其划分５个不同的化石组合,根据介形类种类和组合所提供的环境信息,并结合沉积特征和年代学研究,可将２４万年来以的甜水海古湖泊演化分为６个阶段：前４段（２４２－５９ｋａＢＰ）甜水海地区为淡水湖泊与河流交换变化的环境,第５段（５９－  相似文献   

丝光沸石/TiO2复合体的特征及对甲苯光催化降解研究   总被引：5，自引：2，他引：3  

吴平霄  明彩兵 《矿物岩石》2005,25(1):1-5

在TiO2光催化剂的制备过程中加入一定比例的丝光沸石制备了丝光沸石／TiO2复合体光催化剂．对含甲苯废气进行光催化降解实验．同时运用X射线粉末衍射技术、红外光谱、激光拉曼光谱和紫外一可见漫反射光谱等技术对丝光沸石／TiO2复合体的结构特征和光催化性能进行研究结果表明：丝光沸石的加入能够显著地降低复合光催化剂中TiO2的纳米颗粒粒径、增强其对紫外光的吸收,同时复合光催化剂中TiO2与丝光沸石的结构羟基发生反应形成键合,从而增强了复合体的光催化活性。在丝光沸石和TiO2复合的质量配比为1：5时．复合光催化剂对甲苯的光催化降解率最高．达94．58％。  相似文献   

The dynamic and thermodynamic processes dominating the reduction of global land monsoon precipitation driven by anthropogenic aerosols emission     

Zhou  Tianjun  Zhang  Wenxia  Zhang  Lixia  Zhang  Xuebin  Qian  Yun  Peng  Dongdong  Ma  Shuangmei  Dong  Buwen 《中国科学:地球科学(英文版)》2020,63(7):919-933

Changes in monsoon precipitation have profound social and economic impacts as more than two-thirds of the world's population lives in monsoon regions. Observations show a significant reduction in global land monsoon precipitation during the second half of the 20 th century. Understanding the cause of this change, especially possible anthropogenic origins, is important.Here, we compare observed changes in global land monsoon precipitation during 1948–2005 with those simulated by 5 global climate models participating in the Coupled Model Inter-comparison Project-phase 5(CMIP5) under different external forcings.We show that the observed drying trend is consistent with the model simulated response to anthropogenic forcing and to anthropogenic aerosol forcing in particular. We apply the optimal fingerprinting method to quantify anthropogenic influences on precipitation and find that anthropogenic aerosols may have contributed to 102%(62–144% for the 5–95% confidence interval)of the observed decrease in global land monsoon precipitation. A moisture budget analysis indicates that the reduction in precipitation results from reduced vertical moisture advection in response to aerosol forcing. Since much of the monsoon regions,such as India and China, have been experiencing rapid developments with increasing aerosol emissions in the past decedes, our results imply a further reduction in monsoon precipitation in these regions in the future if effective mitigations to reduce aerosol emissions are not deployed. The observed decline of aerosol emission in China since 2006 helps to alleviate the reducing trend of monsoon precipiptaion.  相似文献   

Redox processes in subduction zones: Progress and prospect     

Wang  Jintuan  Xiong  Xiaolin  Chen  Yixiang  Huang  Fangfang 《中国科学:地球科学(英文版)》2020,63(12):1952-1968

Science China Earth Sciences - Oxygen fugacity (fO2) is an intensive variable that describes the redox state of a system. By controlling the valence state of multivalent elements, fO2 affects the...  相似文献   

The origin of arc basalts: New advances and remaining questions     

Xu  Yigang  Wang  Qiang  Tang  Gongjian  Wang  Jun  Li  Hongyan  Zhou  Jinsheng  Li  Qiwei  Qi  Yue  Liu  Pingping  Ma  Lin  Fan  Jingjing 《中国科学:地球科学(英文版)》2020,63(12):1969-1991

Science China Earth Sciences - Whether arc magmatism occurs above oceanic subduction zones is the forefront of studies on convergent plate margins. The most important petrologic issue related to...  相似文献   

土-结构动力相互作用及基础形式对超大型冷却塔结构地震反应的影响分析     

张海燕  唐久林  于敏  刘晋超 《华南地震》2019,39(3):133-140

采用ABAQUS有限元分析软件,分别对基于刚性地基假定的环板基础、考虑土-结构动力相互作用的环板基础和桩基础超大型冷却塔模型进行了模态分析、弹性和弹塑性时程分析,研究了土-结构动力相互作用和基础形式对超大型冷却塔结构动力特性和地震反应的影响。结果表明:当考虑相同阶数的振型时,刚性地基模型的振型参与质量系数最小。地震作用下,刚性地基模型和桩基础模型的加速度响应、支柱内力、塔壳混凝土主应力等一般比考虑土-结构动力相互作用的环板基础模型偏大,但塔顶水平位移偏小。土-结构动力相互作用比基础形式对冷却塔动力特性以及地震反应的影响更大,且二者对冷却塔竖向振动的影响比水平向大。三种模型计算所获得的冷却塔薄弱部位均集中于支柱,且支柱最大侧移角相差不大。  相似文献   

Fractal analysis of a Quaternary fault array in the central Apennines,Italy     

《Journal of Structural Geology》1997,19(7):945-953

  相似文献   

(U-TH)/HE DATING OF INTERNATIONAL STANDARD FISH CANYON TUFF ZIRCON          下载免费PDF全文

WANG Ying  ZHENG De-wen  LI You-juan  WU Ying 《地震地质》2019,41(5):1302-1315

Zircon is one of the most commonly used accessory minerals rich in U and Th for(U-Th)/He dating system. Compared with apatite, zircon has a higher He closure temperature (~190℃), which gives it more advantages in solving the problem of source material and thermal history reconstruction in sedimentary basins. However, the crystals of zircons often have U and Th zoning development, with obvious differences in concentration. Even the standard sample of FCT(Fish Canyon Tuff)zircon which is widely used in (U-Th)/He dating has an average age dispersion of about 10%. In this study, the Alphachron He isotope mass spectrometer is used for laser melting of a batch of single grains of FCT zircon(11 grains)to determine their ⁴He content. The contents of U and Th of parent isotopes are accurately determined by automatic injection of Agilent 7900 ICP-MS and isotope diluent method. The Th/U ratios of the 10 FCT zircons calculated with (U-Th)/He average age in this paper range from 0.52 to 0.67, which are consistent with the Th/U ratios of 186 reported so far. According to the Th/U ratios of 189 FCT zircons published in the statistical literature, we found that only three of them had high Th/U ratios, namely, 1.12, 1.16 and 1.5, the other 186 FCT zircons(occupy>98%) had a Th/U ratio less than 1. Based on previous results and the 10 Th/U ratios measured in this paper, 196 FCT zircons have a normal Th/U ratio ranging from 0.27 to 1.00, with an average ratio of 0.56(n=196). Excluding one abnormally old age, the(U-Th)/He ages of the remaining FCT zircons in this study range from 26.61 to 31.91Ma, with a weighted mean age of (28.8±3.1)Ma (2SD, n=10), which is consistent with the mean age ((28.3±3.1)Ma, 2σ, n=127) or (28.29±2.6)Ma(2σ external error, 9.3%, n=114)obtained by several other international laboratories. This indicates that the zircon single particle(U-Th)/He dating process established by our laboratory is reliable. For the zircon samples with U, Th banding and concentration differences prevailing, determining the distribution of U, Th elements in the crystal prior to the (U-Th)/He experiment is essential for understanding effects of geometry and elemental zoning on nuclear recoil and diffusion and the interpretation of (U-Th)/He age data.  相似文献