Smectite formation in metalliferous sediments near the East Pacific Rise at 13°N   总被引：1，自引：0，他引：1  

荣坤波  曾志刚  殷学博  陈帅  王晓媛  齐海燕  马瑶 《海洋学报(英文版)》2018,37(9):67-81

A 43 cm long E271 sediment core collected near the East Pacific Rise(EPR) at 13°N were studied to investigate the origin of smectite for understanding better the geochemical behavior of hydrothermal material after deposition.E271 sediments are typical metalliferous sediments. After removal of organic matter, carbonate, biogenic opal,and Fe-Mn oxide by a series of chemical procedures, clay minerals(2 μm) were investigated by X-ray diffraction,chemical analysis and Si isotope analysis. Due to the influence of seafloor hydrothermal activity and close to continent, the sources of clay minerals are complex. Illite, chlorite and kaolinite are suggested to be transported from either North or Central America by rivers or winds, but smectite is authigenic. It is enriched in iron, and its contents are highest in clay minerals. Data show that smectite is most likely formed by the reaction of hydrothermal Fe-oxyhydroxide with silica and seawater in metalliferous sediments. The Si that participates in this reaction may be derived from siliceous microfossils(diatoms or radiolarians), hydrothermal fluids, or detrital mineral phases. And their δ30 Si values are higher than those of authigenic smectites, which implies that a Si isotope fractionation occurs during the formation because of the selective absorption of light Si isotopes onto Feoxyhydroxides. Sm/Fe mass ratios(a proxy for overall REE/Fe ratio) in E271 clay minerals are lower than those in metalliferous sediments, as well as distal hydrothermal plume particles and terrigenous clay minerals. This result suggests that some REE are lost during the smectite formation, perhaps because their large ionic radii of REE scavenged by Fe-oxyhydroxides preclude substitution in either tetrahedral or octahedral lattice sites of this mineral structure, which decreases the value of metalliferous sediments as a potential resource for REE.  相似文献   

东太平洋海隆13°N表层含金属沉积物物质组成与元素赋存状态     

荣坤波  曾志刚  武力  李康 《海洋科学》2018,42(7):70-79

为了解不同类型含金属沉积物在物质组成和元素赋存状态的差异,对东太平洋海隆13°N洋中脊两侧表层含金属沉积物(站号:E271和E53)进行了矿物学、地球化学分析,顺序提取实验,并与前人对轴部表层沉积物(站号:17A-EPR-TVG1)的研究结果作了对比分析。研究结果表明, E271和E53是远端含金属沉积物,由非浮力热液羽状流中颗粒物沉降所形成的;17A-EPR-TVG1沉积物是近喷口含金属沉积物,由黑烟囱或者热液硫化物丘状体崩塌、堆积,或者由热液羽状流中Fe-Mn氧化物和硫化物快速沉淀而形成的,近喷口沉积物比远端沉积物更富集Fe、Cu和Zn等元素。元素在两种含金属沉积物中的赋存状态基本相同,除了Fe,Cu,Zn,Mo和稀土元素(REE)等元素在远端沉积物中主要存在于Fe-Mn氧化物相,在近喷口沉积物中主要在残留相中。远端沉积物中REE页岩标准化配分模式与海水相似,表明REE主要来自海水,而近喷口沉积物中REE配分模式与热液流体相似,说明REE以高温热液流体来源为主。相关研究结果加深了对热液沉积作用研究的认识。  相似文献   

一种基于熵权法的小波去噪复合评价指标   总被引：2，自引：0，他引：2  

容静  刘立龙  康昊华  李松青  周吕 《大地测量与地球动力学》2018,38(7):689-694

传统的评价指标在真值未知的情况下不能满足小波去噪质量评价的要求。为此,借助变化率特征重新构建均方根误差变化量和平滑度变化量两个指标,利用熵权法定权将归一化后的两个指标线性组合,所得到的新指标即为复合评价指标。该方法借助指标的变化率随分解层数的增加表现出明显的收敛特性来确定去噪最优分解层数。实验表明,该方法能够在真值未知的情况下准确地指导小波分解,确定去噪最优分解层数,从而达到最优去噪效果。  相似文献   

河嘉203H含硫水平气井测试工艺实践     

唐波  乔智国  陈伟  叶翠莲 《海洋地质译丛》2010,(4):103-105

河嘉203H井是川东北河坝构造嘉二高压含硫气藏部署的第一口水平井,具有埋藏深、储层压力高、腐蚀分压高、地层易漏失、水平井压井堵漏难度大的特点,通过开展工具优选、管柱结构优化设计、流程优选,并对替浆、放喷油嘴控制及压井等主要工序的施工工艺参数进行研究,形成了河坝嘉二含硫气藏水平井测试工艺技术体系,并在河嘉203H井获得成功应用。  相似文献   

20世纪80和90年代华北干旱特征及成因分析   总被引：7，自引：2，他引：5  

荣艳淑  余锦华  段丽瑶 《高原气象》2007,26(2):319-325

在全球气候变暖背景下,20世纪80年代和90年代几乎有一半的年份出现干旱,90年代华北的干旱频率比80年代更高。本文从干旱基本状况、干旱强度和干旱空间分布出发,对华北地区这两个年代的干旱进行了比较,并从对全球气候变暖的响应和大气环流场特征等方面,探讨了这两个年代干旱的成因。研究表明,在干旱强度和空间分布上,90年代明显强于80年代。对全球气候变暖的响应90年代明显强于80年代,表现了更显著的增暖趋势。80年代的干旱年中北极涛动显著增强,中高纬度地区为气压正距平带控制;90年代的干旱年中北半球中高纬度地区为正负距平波列相间分布,存在EU和PNA遥相关型。本文还定义了西伯利亚高压指数,该指数90年代显著高于80年代,且与华北地区降水显著相关,可以作为华北地区旱涝预测的指标。  相似文献   

A NUMERICAL MODEL FOR SEDIMENTATION IN FENHE RESERVOIR AND THE ADJOINING REACHES     

GUAN Yiexiang  RONG Fengtao  WANG Jingxin  YIN Lisheng  WANG Hongtu Project Engineer  Hydraulic Research Institute  Shanxi Province  China  Vice Chief Engineer  Senior Engineer  Water Resources 《国际泥沙研究》1991,(1)

In this paper, a numerical model for sedimentation in Fenhe Reservoir and the adjoining reaches has been presented on the basis of the theory of non-equilibrium sediment transport. The model is calibrated by using a part of the sediment data collected for Fenhe Reservoir and checked by simulating the remaining data. Moreover, the method of optimization in nonlinear programming has been applied to determine the basic parameters of the model applying a concept of fuzzy mathematics to formulate the objective functions. The computed amounts of reservoir deposition and channel deformation arc found to be substantially in agreement with the values observed.  相似文献   

SOIL SHEAR STRENGTH: AN INDICATOR FOR ERODIBILITY OF THE LOESS SOILS   总被引：1，自引：0，他引：1  

WANG Guiping  WEI Zhongping  ZHANG Zhiguo 《国际泥沙研究》1994,(1)

ＳＯＩＬＳＨＥＡＲＳＴＲＥＮＧＴＨ：ＡＮＩＮＤＩＣＡＴＯＲＦＯＲＥＲＯＤＩＢＩＬＩＴＹＯＦＴＨＥＬＯＥＳＳＳＯＩＬＳＷＡＮＧＧｕｉｐｉｎｇ；ＷＥＩＺｈｏｎｇｐｉｎｇａｎｄＺＨＡＮＧＺｈｉｇｕｏＡｂｓｔｒａｃｔ：ＦｉｅｌｄｅｘｐｅｒｉｍｅｎｔＳｕｎｄｅ...  相似文献   

新疆托里蛇绿岩型金矿床中黄铁矿的研究     

甘源明  周美付  冯延玲  戎合  袁嘉琪 《地球学报》1987,9(3):81-88

在金的伴生矿物中,黄铁矿在托里金矿床中是非常丰富的矿物。它不仅在数量上占优势,而且在本矿床中黄铁矿还以部分自然金的载体出现在矿化带中,所以对黄铁矿进行较为详细的研究是有实际意义的。另外,本矿床为一新型的金矿床——蛇绿岩型金矿,就其黄铁矿来说,无论是矿物学的特点或是地球化学特点都具有本类型矿床的独特性质,例如本黄铁矿中有CO/Ni<1、Au/Ag>1的特点。再者,托里金矿有两个成矿带,而黄铁矿在这两个成矿带中又有不同的特点,这是由于这两个成矿带不同的成矿环境所造成的。  相似文献   

Study on Uncertainties of Seismicity Parameters b and ν_4 in Seismic Statistical Zones     

Pan Hua  Li Jinchen  Li Zhiguo Institute of Geophysics  China Earthquake Administration  Beijing  China 《中国地震研究》2007,(3)

For several seismic statistical zones in North China,the key factors causing uncertainties in the important seismicity parameters b and ν_4 and the features of their uncertainties are discussed in this paper.The magnitude of uncertainty is also analyzed.It can be seen that the key influencing factors are statistical period,methods of processing statistical samples,lower limit magnitude and the annual average occurrence ratio of large earthquakes.The variation ranges of b and ν_4 in the Tancheng-Lujiang zone are as high as 0.2 and 1.4 respectively,which are similar to those in the Fenwei zone.They are much smaller however in the Hebei zone because of its sufficient statistical samples.  相似文献   

成矿预测中应用GIS的主要步骤   总被引：8，自引：0，他引：8       下载免费PDF全文

刘治国  池顺都  周顺平 《地质找矿论丛》2002,17(2):140-144

GIS在成矿预测中需要处理的成矿信息包括遥感信息，地质信息，物探信息和化探信息；GIS支持下的成矿预测包括资料收集，各类数据的准备和数据库的建立，控矿因素分析，建立找矿预测模型，空间检索与分析，特征提取与合并，结果修正的地质解释，预测成果的输出等步骤；GIS工具的应用为成矿预测提供了又一条有效的途径。  相似文献