东南极格罗夫山泛非期麻粒岩相变质作用     

刘晓春 赵越刘小汉  赵子然 《地质论评》2003,49(4):422-431

东南极格罗夫山主要由麻粒岩相高级变质岩和花岗岩类组成，其中变质岩以浅色和暗色含斜方辉石长英质片麻岩占主导地位，夹有少量镁铁质麻粒岩、变沉积岩和含方柱石钙硅酸盐岩。这些岩石一般都展示了平衡的矿物共生结构，但在镁铁质麻粒岩的单斜辉石中普遍发育斜方辉石(易变辉石)的出溶片晶。根据出溶辉石的重组分析获得麻粒岩相变质作用的峰期温度约为850℃，而浅色片麻岩中的石榴子石—斜方辉石—斜长石—石英组合给出的变质压力为0．61～0．67GPa。镁铁质麻粒岩中火成亚钙质普通辉石斑晶的保存表明格罗夫山地区可能只发育单一的泛非期高温麻粒岩相变质事件，岩石在高温变质之后经历了缓慢冷却过程，这主要归因于花岗质岩浆的板底垫托作用。  相似文献   

遗传算法与单纯形法组合的影像纹理分类方法   总被引：7，自引：3，他引：7  

郑肇葆 《测绘学报》2003,32(4):325-329

提出遗传算法(简称GA)与单纯形法组合的影像纹理分类方法(简称GASPX)。单纯形法是一种局部搜索方法，它通过反射，扩张，收缩操作，求得新的单纯形点，组成新单纯形，新单纯形比前一个单纯形更接近局部最优解。这种寻优方法收敛速度快，它与GA组合起来可以改善单独使用GA收敛速度慢的缺陷。由于在组合算法中是多个单纯形的局部区域的并行搜索，避免GA优化过程中过早收敛于局部最优解的现象出现。通过5种不同类别航空影像纹理识别的试验，并与GA的结果作对比，结果表明GASPX法优于GA法。  相似文献   

高分辨率卫星影像中阴影的自动提取与处理   总被引：27，自引：0，他引：27  

许妙忠  余志惠 《测绘信息与工程》2003,28(1):20-22

高分辨率卫星遥感影像开创了许多新的应用领域，但影像中的阴影是一个必须解决的问题。一方面，它给象影像分类这样的一些应用带来了很大麻烦，另一方面，它提供了物体的高度信息。本文利用纹理分析的方法，通过共生矩阵和相应指数的计算，对高分辨率卫影像中阴影的自动提取与处理作了一个尝试并给出了一些结果。  相似文献   

指派交叉--一种新的遗传交叉方法     

郑肇葆 《武汉大学学报(信息科学版)》2003,28(3):272-276

在用遗传算法生成影像纹理分类的“Tuned”模板中，引用了一个新的遗传交叉方法——指派交叉，与其他的交叉方法相比，指派交叉可在相同的搜索空间中提供更好的优化组合。试验证明，指派交叉是值得推广的一种遗传交叉方法。  相似文献   

三维GIS中建筑物的若干问题探讨   总被引：21，自引：1，他引：21  

谭仁春  江文萍  杜清运 《测绘工程》2003,12(1):20-23

随着GIS向三维领域的不断发展，三维GIS中实体目标的数据获取和建模显得越来越重要。以三维GIS中的建筑物作为研究对象，分别从建筑物的各类数据的获取方法和模型建立技术等方面进行了深入分析，并着重介绍了基于数字地图资料的数据获取和建模方法。  相似文献   

An Unusual Texture: Skeletal Sphalerite in Pyrite from Dajing Tin-polymetallic Deposit, China     

Yu Wang Wang    Jing Bin Wang  Li Juan Wang 《Resource Geology》2003,53(1):67-72

Abstract. Skeletal sphalerite with stellar, cruciform and snowflake-like (or cauliflower-like) shapes included in pyrite is widely found in the Dajing tin-polymetallic deposit. It occurs only in chalcopyrite-pyrite mineralization stage. The compositions of all sphalerites in the chalcopyrite-pyrite stage are characterized by high Cu content (3.9 - 7.0 wt% with a mean of 5.4 wt%), while the skeletal crystal sphalerite has higher zinc and cadmium contents, and lower copper and iron contents, compared with other sphalerites of the same stage. The skeletal crystal sphalerite in pyrite is possibly generated by exsolution.  相似文献   

From geometry to dynamics of microstructure: using boundary lengths to quantify boundary misorientations and anisotropy   总被引：1，自引：0，他引：1  

John Wheeler  Z. Jiang  D. J. Prior  J. Tullis  M. R. Drury  P. W. Trimby 《Tectonophysics》2003,376(1-2):19-35

The microstructure of a quartzite experimentally deformed and partially recrystallised at 900 °C, 1.2 GPa confining pressure and strain rate 10⁻⁶/s was investigated using orientation contrast and electron backscatter diffraction (EBSD). Boundaries between misoriented domains (grains or subgrains) were determined by image analysis of orientation contrast images. In each domain, EBSD measurements gave the complete quartz lattice orientation and enabled calculation of misorientation angles across every domain boundary. Results are analysed in terms of the boundary density, which for any range of misorientations is the boundary length for that range divided by image area. This allows a more direct comparison of misorientation statistics between different parts of a sample than does a treatment in terms of boundary number.The strain in the quartzite sample is heterogeneous. A 100×150 μm low-strain partially recrystallised subarea C was compared with a high-strain completely recrystallised subarea E. The density of high-angle (>10°) boundaries in E is roughly double that in C, reflecting the greater degree of recrystallisation. Low-angle boundaries in C and E are produced by subgrain rotation. In the low-angle range 0–10° boundary densities in both C and E show an exponential decrease with increasing misorientation. The densities scale with exp(−θ/λ) where λ is approximately 2° in C and 1° in E; in other words, E has a comparative dearth of boundaries in the 8–10° range. We explain this dearth in terms of mobile high-angle boundaries sweeping through and consuming low-angle boundaries as the latter increase misorientation through time. In E, the density of high-angle boundaries is larger than in C, so this sweeping would have been more efficient and could explain the relative paucity of 8–10° boundaries.The boundary density can be generalised to a directional property that gives the degree of anisotropy of the boundary network and its preferred orientation. Despite the imposed strain, the analysed samples show that boundaries are not, on average, strongly aligned. This is a function of the strong sinuosity of high-angle boundaries, caused by grain boundary migration. Low-angle boundaries might be expected, on average, to be aligned in relation to imposed strain but this is not found.Boundary densities and their generalisation in terms of directional properties provide objective measures of microstructure. In this study the patterns they show are interpreted in terms of combined subgrain rotation and migration recrystallisation, but it may be that other microstructural processes give distinctive patterns when analysed in this fashion.  相似文献   

安山岩中黄铜矿矿石分析和制硫酸铜工艺的研究   总被引：2，自引：0，他引：2  

朱继存 《化工矿产地质》1997,19(1):63-68

安山岩中的黄铜矿是庐江中生代陆相火山热液型铜矿床的原生矿，矿石中主要伴生黄铁矿及少量斑铜矿、赤铁矿和褐铁矿。物相分析结果，黄铜矿的粒度很细，只有细磨才能单体解离；它在矿石中分布极不均匀，且与脉石矿物接触疏松，适于粗磨抛尾。物性分析结果，黄铜矿在４００～５３０℃、斑铜矿在４５０～６００℃、黄铁矿在５００～６８０℃氧化分解。实验研究表明，矿石经磨碎磁选，大部分的粗粒级的铁矿物能够回收；粗磨抛尾可获得铜、硫的粗精矿；然后再经硫酸化焙烧、酸浸、过滤、提纯、浓缩结晶可制得工业级硫酸铜。浸渣做炼铁原料，黄钾铁矾做Ｆｅ２Ｏ３颜料，有时还可回收金、银。  相似文献   

Effect of environmental factors on the flora of alluvial fans in southern Sinai     

Abd El-Raouf A. Moustafa  A. Zayed 《Journal of Arid Environments》1996,32(4):431-443

The purpose of this study was to elucidate the floristic and structural characteristics of simple alluvial fan vegetation of southern Sinai and to relate them to environmental variation. The main question addressed was: how does the floristic composition of fan habitats, species richness and life-form vary in relation to environmental change? Thirty-seven alluvial fans, randomly selected in two mainwadis(WadiFeiran andWadiDahab) were analysed quantitively. Two-way Indicator Species Analysis (TWINSPAN) classification and Canonical Correspondence Analysis (CCA) were applied in successive stages of the data analysis to describe vegetational variation in relation to physical gradients. Seven main clusters of fans were defined on the basis of environmental variation. These clusters are divided into three main groups of species richness. Species richness varied along a moisture gradient. The richest fans were the driest habitats, indicating that maximum species richness did not occur at high moisture availability. The moisture gradient is a complex gradient correlated with elevation, slope, climatic aridity, soil texture and the nature of the soil surface. Fine sand, silt plus clay and calcium carbonate showed significant differences between the internal groups and subgroups of the first and second level of the TWINSPAN classification.  相似文献   

混合岩中斜长石的交代净边结构和倒转双晶研究——以大别罗田黄土岭长英片麻岩为例   总被引：3，自引：0，他引：3  

游振东  钟增球  汤中道  陈能松 《地球科学》1996,(5)

湖北罗田黄土岭长英片麻岩是与紫苏石榴黑云片麻岩共生的浅色片麻岩，成分上近于Ａ型花岗岩．受到浅混合岩化，钾交代现象显著．在斜长石与钾长石新成体接触处有清楚的交代净边结构，背散射电子探针分析表明，净边成分为钠长石（Ａｂ８９～９７）．在净边结构上，发现叠加倒转双晶．净边结构产生于长英片麻岩部分熔融的高温条件下，与整个大别地体隆升过程和Ａ型花岗岩的生成有成因联系  相似文献