甘新蒙北山地区成矿带划分和基本特征对比   总被引：3，自引：1，他引：2  

彭巨贵  张发荣  赵福昌 《地球科学与环境学报》2006,28(3):11-18

在对甘新蒙北山地区成矿地质背景和成矿在时空上的联系性等综合研究分析基础上,运用新理论、新认识,以板块构造单元划分为基础,将本区划分为3个Ⅲ级成矿带、11个Ⅳ级成矿带,并对Ⅲ级成矿带特征进行了阐述,以期为矿产勘查和地质大调查工作部署提供新的思路和依据。进一步就主要矿床(点)、构造单元、矿种、赋矿建造、控矿因素、成矿类型、成矿时代等方面进行了对比,认为各Ⅳ级成矿带在区域上具有相对稳定的展布范围,具有相同的构造环境和成矿条件、类似的矿种和成矿时代,存在一定的相似性、可比性,并且各成矿带具有一定的潜在找矿价值。  相似文献   

太阳表面米粒结构观测对比度分析     

饶长辉  姜文汉  凌宁 《天文学报》2001,42(2):134-139

分析以观测系统焦面上和探测器测到的太阳表面米粒结构的对比度与观测系统口径，大气湍流相干长度以及系统探测灵敏度的关系，给出了不同口径，不同大气湍流相干长度以及不同系统探测灵敏度时的米粒结构对比值计算结果，此外还给出了实验结果。  相似文献   

密度和压缩系数的散射层析成像法   总被引：1，自引：1，他引：0  

袁晓晖  王妙月 《地球物理学报》1991,34(6):753-761

本文在速度成像的基础上研究了同时对密度和压缩系数成像的散射波层析成像法.对不同散射角度的计算可以得到一系列反演图像,拟合这些图像,从而可以有效地达到对密度和压缩系数（或速度）成像的目的.与单纯的速度成像相比,增加了反演的难度.首先是对资料的方位性要求增加;其次是对资料的利用率下降.即便如此,从对较少量的炮点和检波点资料的数值计算来看,仍取得了满意的成像结果.我们对组成字母“A”的散射体结构进行了成像计算,结果能够同时再现密度和压缩系数,成像清晰,表明了方法的可行性,并能应用于复杂结构的成像问题.  相似文献   

Optimizing interpolation of shoot density data from a Posidonia oceanica seagrass bed   总被引：1，自引：0，他引：1  

Michele Scardi  Lorenzo A. Chessa  Eugenio Fresi  Antonio Pais  & Simone Serra 《Marine Ecology》2006,27(4):339-349

A case study on the optimization of Posidonia oceanica density interpolation, using a data set from a large meadow at Porto Conte Bay (NW Sardinia, Italy), is presented. Ordinary point kriging, cokriging and a weighted average based on inverse square distance were used to interpolate density data measured in 36 sampling stations. The results obtained from different methods were then compared by means of a leave‐one‐out cross‐validation procedure. The scale at which interpolation was carried out was defined on the basis of the Hausdorff dimension of the variogram. Optimizing spatial scale and data points search strategy allowed obtaining more accurate density estimates independently of the interpolation method.  相似文献   

秦皇岛砂滩海洋线虫的数量研究   总被引：4，自引：2，他引：4  

张志南 《中国海洋大学学报(自然科学版)》1991,(1)

在两年的周期内,对秦皇岛4个砂滩的海洋线虫进行了6次芯样采集。灯塔、新煤码头、汤河口和北戴河赤土山4个砂滩均系分选好的细砂或中细砂,其中值粒径为140-285μm。对连续16个芯样计数的变异性所做的测试证明,1,2和3个芯样计算所得95％C.L.分别是0.539X—1.855X,0.647X—1.547X和0.700X—1.428X。秦皇岛砂滩海洋线虫的年平均密度:中潮带上区为1381±441 inds.10cm~(-2)。中潮带下区为1264±538 inds.10cm~(-2)。灯塔和新煤码头砂滩,8月出现高密度值,与温度的季节变化相符合,而汤河口则出现最低值,可能与污染物的大量排出有关。多数砂滩的大部分芯样显示了明显的重直分布,即种群数量的大部分集中在芯样顶部的两个分层:0～4和5～8cm。没有发现垂直分布的季节变化趋势。与世界其他海区砂滩的资料进行了比较。  相似文献   

长江口海水的密度   总被引：1，自引：1，他引：1  

陈国华  胡博路  张力军  季荣  金建成 《海洋与湖沼》1992,23(6):573-580

为了核对1980年国际海水状态方程应用于中国近岸海水的可靠性,高精度的磁力浮沉子密度计在15—25℃,盐度5—35,一个大气压条件下,测量了长江口附近海水及其人工稀释海水的相对密度。结果表明,海水密度直接测量值系统地偏高于状态方程计算值,二者之间的偏差随水样盐度值降低而增大,且与海水[Ca~(2+))/s比值成明显正相关关系。经计算机拟合,导出了长江口附近海水及其稀释海水的状态方程,该方程计算值与实验值的平均标准偏差为±3.9×10~(-3)kg/m~3。  相似文献   

Approaches for comparative evaluation of raster GIS-based landslide susceptibility zonation maps     

R.P. Gupta  D.P. Kanungo  M.K. Arora  S. Sarkar 《International Journal of Applied Earth Observation and Geoinformation》2008

Evaluation of maps generated from different conceptual models or data processing approaches at spatial level has importance in many geoenvironmental applications. This paper addresses the spatial comparison of different landslide susceptibility zonation (LSZ) raster maps of the same area derived from various procedures.  相似文献   

基于最小二乘配置的三维空间坐标转换   总被引：1，自引：0，他引：1  

李潇  尹晖 《测绘工程》2008,17(2):16-19

在求解未知转换参数时,鉴于公共点坐标本身的误差,提出利用最小二乘配置法进行空间坐标转换,即将公共点本身坐标作为随机参数,把转换参数作为非随机参数进行处理,最后通过实验对比分析表明,该方法明显优于一般坐标转换方法。  相似文献   

Mongolian gerbils and Daurian pikas responded differently to changes in precipitation in the Inner Mongolian grasslands     

G. Wang  W. Zhong 《Journal of Arid Environments》2006,66(4):648-656

Mongolian gerbils (Meriones unguiculatus) and Daurian pikas (Ochotona dauurica) are two key small mammal species in the Inner Mongolian grasslands, China. Mongolian gerbils displayed density-dependent population growth, but the time lag of density dependence was short and within season. The spring–autumn population growth rate was inversely related to population density in Mongolian gerbils of the Erdos desert grasslands. The autumn–spring population growth rate of Mongolian gerbils was inversely related to winter precipitation. Precipitation had stronger effects on the population growth of gerbils during the non-breeding season. The monthly population growth rate of Daurian pikas was positively related to the monthly precipitation and was inversely related to population density in central Inner Mongolia. Daurian pikas select habitats with tall plants. Increased precipitation enhances plant production and increases the height of plants in arid and semi-arid regions. This enhancement of plant height might increase the population growth of Daurian pikas. Mongolian gerbils live in short grasslands. Increased winter precipitation might result in higher winter mortality of Mongolia gerbils, or taller plants might supress gerbil population growth in wet years. Therefore, responses of small mammal species to changes in precipitation depend on the life history of small mammals and changes in vegetation induced by climatic changes.  相似文献   

Contrast in Fluid M etallogeny between the Tianmashan Au-S Deposit and the Datuanshan Cu Deposit in Tongling, Anhui Province     

LEE Hyun Koo 《《地质学报》英文版》2003,77(1):116-124

A comprehensive contrast of ore-forming geological background and ore-forming fluid features, especially fluid ore-forming processes, has been performed between the Tianmashan and the Datuanshan ore deposits in Tongling, Anhui Province. The major reasons for the formation of the stratabound skarn Au-S ore deposit in Tianmashan and the stratabound skarn Cu ore deposit in Datuanshan are analyzed in accordance with this contrast. The magmatic pluton in Tianmashan is rich in Au and poor in Cu, but that in Datuanshan is rich in Cu and Au. The wallrock strata in Tianmashan contain Au-bearing pyrite layers with some organic substance but those in Datuanshan contain no such layers. Moreover, the ore-forming fluids in Tianmashan are dominantly magmatic ones at the oxide and sulfide stages, but those with high content of Cu in Datuanshan are mainly groundwater fluids. In addition, differences in compositional evolution and physicochemical condition variation of the ore-forming fluids result in gradual dispersion  相似文献