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戴苗  刘坚  蒋玲霞  赵凌云  张念 《大地测量与地球动力学》2014,34(3):48-51

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Rare earth elements in cold seep carbonates from the southwestern Dongsha area,northern South China Sea     

《Marine and Petroleum Geology》2014

The circulation of methane-rich fluids at cold seeps often leads to the precipitation of seep carbonates close to the seafloor along continental margins, which can be used as records of past fluid seepage. Rare earth element (REE) concentrations in seep carbonates have been used to trace fluid sources and provide information on associated biogeochemical processes at cold seeps. The REE concentrations of a series of carbonates collected from cold seeps in the southwestern Dongsha area of the northern South China Sea are analyzed in this study. The total REE contents (ΣREE) of the seep carbonates analyzed show a wide variation from 17 ppm to 523 ppm with an average ΣREE value of 54 ppm, which are higher than the typical marine carbonate values of ∼28 ppm commonly reported and also higher than those of the carbonates from other cold seep areas. A positive correlation between Fe–Mn content and ΣREE was observed. These results suggest that the seep carbonates of this study were primarily controlled by the methane-derived fluid from which they precipitated. The Fe-rich dolomite and siderite, which are the main components of the carbonates, are responsible for the enrichment of the REE. A slight positive Ce anomaly observed in the shale-normalized REE patterns of the studied seep carbonates suggests that they formed in anoxic conditions, and the correlations between Ce/Ce* and La_N/Sm_N, Ce/Ce* and Dy_N/Sm_N, Ce/Ce* and ΣREE further reveal that the REE characteristics of most seep carbonate samples preserve the original redox conditions in which they precipitated and late diagenesis has had little effect on the REE. However, the REE characteristics of sub-samples DS2-2B, DS1-6A and DS1-7A are very different from those of the other sub-samples, indicating a greater impact of late diagenesis and post-oxidation favored REE enrichment.  相似文献   

GOCE地球重力场模型在青藏地区的评价及分析     

高春春 陆洋张子占  史红岭杜宗亮 朱传东 《测绘学报》2014,43(1):21-29

2009年GOCE卫星升空以后,卫星重力梯度数据参与解算的GOCE系列重力场模型已有多家研究机构相继公布。本文分别采用青藏地区的GPS/水准和重力异常实测数据对GOCE重力场模型进行了外部测试,并在重力异常验证过程中引入了一种新的滤波方法,验证结果表明在青藏地区GOCE重力场模型相比其它系列模型的优势在于中波段。同时,探讨了GOCE重力场模型与其他系列模型在青藏地区主要差异值的空间分布以及首次利用统计分析方法找出模型之间主要差异值的阶次分布,得出如下结论：模型之间的较大差异值在空间水平方向上主要分布在喜马拉雅山脉、天山等地形起伏较大的区域,在垂直方向上主要集中在岩石圈。  相似文献   

地理国情普查地表覆盖数据分类方法研究     

任立欣  岳昊  刘春红 《东北测绘》2014,(6):72-74

对三种常见的地理国情普查地表覆盖数据分类方法进行了试验比较,得出在遥感影像质量、基础地理信息数据、遥感样本和技术人员水平等不同的条件下,三种方法的适宜使用条件,对普查生产实际具有现实指导意义。  相似文献   

测绘导航与地理信息科学技术的进展--庆祝?测绘科学技术学报?创刊30周年   总被引：1，自引：0，他引：1  

王家耀 《测绘科学技术学报》2014,(5)

从6个方面对军事测绘导航和地理空间信息科学技术的发展进行了回顾和展望：一是时空基准的现代化,为构建统一时空系统奠定了基础;二是北斗导航定位系统步入国际先进行列,目前正在由区域增强型向高精度全球化过度;三是对地观测数据获取技术取得了长足的进步,天绘和资源卫星三号测绘卫星发挥着越来越重要的作用;四是空间数据综合的自动化、智能化研究取得了举世瞩目的成果,多源异构地理空间数据的集成、融合与同化已成为关注和研究的热点;五是网络服务、网格服务和云服务技术的发展,促使并加快了由地理信息系统到地理信息服务的进程;六是基于网格的地理空间信息获取、处理(生产)和应用(服务)的一体化是今后一个时期的重要研究任务。  相似文献   

Use of earth observation data for applications in public health     

Qihao Weng  Bing Xu  Xuefei Hu  Hua Liu 《国际地球制图》2014,29(1):3-16

The Earth Observation (EO) data with their advantages in spectral, spatial and temporal resolutions have demonstrated their great value in providing information about many of the components that comprise environmental systems and ecosystems for decades that are crucial to the understating of public health issues. This literature review shows that in conjunction with in situ data collection, EO data have been used to observe, monitor, measure and model many environmental variables that are associated with disease vectors. Furthermore, satellite derived aerosol optical depth has been increasingly employed to estimate ground-level PM_2.5 concentrations, which have been found to associate with various health outcomes such as cardiovascular and respiratory diseases. It is suggested that Landsat-like imagery data may provide important data sources to analyse and understand contagious and infectious diseases at the local and regional scales, which are tied to urbanisation and associated impacts on the environment. There is also a great need of data products from coarse resolution imagery, such as those from moderate resolution imaging spectrometer, multiangle imaging spectroradiometer and geostationary operational environmental satellite , to model and characterise infectious diseases at the continental and global scales. The infectious diseases at greater geographical scales have become unprecedentedly significant as global climate change and the process of globalisation intensify. The relationship between infectious diseases and environmental characteristic have been explored by using statistical, geostatistical and physical models, with recent emphasis on the use of machine-learning techniques such as artificial neural networks. Lastly, we suggest that the planned HyspIRI mission is crucial for observing, measuring and modelling environmental variables impacting various diseases as it will improve both spectral resolution and revisit time, thus contributing to better prediction of occurrence of infectious diseases, target intervention and tracking of epidemic events.  相似文献   

数字地球及其应用前景分析     

李力 《测绘与空间地理信息》2011,(6):111-112

数字地球概念是20世纪90年代提出来的一个新概念,该概念一经提出,就受到国际知识界、科技界的关注。进入21世纪,世界主要大国对数字地球系统的建立更加重视。文章介绍了数字地球概念提出的背景,并对数字地球在各个领域的应用前景进行了论述。  相似文献   

全球不同地区强震与地球自转之间的关系分析     

陈学忠  陆小华 《国际地震动态》2011,(12):34-40

对全球及一些地区地震在地球自转速率长周期变化的加速和减速段里年发生次数进行了分析,得到的结果表明,就全球地震而言,减速期7级以上地震年发生次数似乎略高于加速期,8级以上地震年发生次数似乎相当,没有明显差异,8.5级以上地震年发生次数似乎比加速期里高.太平洋东带和太平洋北带的地震,在减速期的年发生次数似乎一致地比加速期略...  相似文献   

甘肃武都典型夯土民房承重墙体抗剪强度试验研究     

徐舜华  王兰民  王强  袁中夏 《地震工程学报》2011,33(4):354-358,385

武都是甘肃省典型夯土民房使用地区.试验中使用武都当地常用土料,完全按照当地施工工艺夯筑两片夯土墙体试件,利用伪静力方法研究墙体抗剪强度.结果显示:(1)上覆荷载对夯土墙体的水平承载力和变形影响较大,随着上覆荷载从10 kN增加到18 kN,开裂荷载和极限荷载分别增加了217％和359％,极限顶点位移则降低了30％;(2)在水平往复荷载的作用下,夯土墙体始终沿着夯土层间水平和垂直接触裂缝处产生破坏,最终碎裂成块体.最后提出了使用铁丝网来加固现存夯土民房承重墙体的建议.  相似文献   

地震前兆数据异常自动检测报警系统   总被引：2，自引：0，他引：2  

张兴国  王子影  李盛乐  刘坚 《地震地磁观测与研究》2011,32(1):101-108

通过对地震前兆数据的分析与研究,研制了一套地震前兆数据异常自动检测与报警系统.该系统可实现测项分量与检测方法的自由定制,通过利用相关分析、差分检测、固体潮相关检测、方差检测、台阶检测与金日光第四统计力学群子统计理论等多种检测方法,实现了对数据的自动异常检测与报警.试验证明,该系统有效可行,可为地震数据监测人员与地震预报...  相似文献