复合褶皱数学模型的应用     

刘德良  杨晓勇  陈增兵 《安徽地质》1995,(4)

为便于对褶皱构造的几何形态进行描述、概括和实际应用，在划分出两个基本类型褶皱的基础上，用数学方程式对五种叠加褶皱进行了表述，这样，利用计算机可以快速准确地获得叠加褶皱的具体形态。  相似文献   

盆地地史模拟述评   总被引：9，自引：0，他引：9  

叶加仁  陆明德 《地质科技情报》1995,14(2):45-51

论述了盆地地史模拟的一般研究方法，认为回剥法是现今重建盆地沉积史与构造史最精确的方法详细讨论了地坟实校正、不整合处理和构造沉隆分析等主要数学模型及其适用范围；并在介绍地史模拟研究历史和研究现状的基础上，指出了地史模拟的发展方向。  相似文献   

A review of mathematical models of river planform changes     

Erik Mosselman 《地球表面变化过程与地形》1995,20(7):661-670

Different mathematical models of river planform changes exist or are being developed. They are reviewed here by discussing a two-dimensional depth-averaged model, various meander models and a model for the braided Brahmaputra-Jamuna River in Bangladesh. Much emphasis is placed on topics where further research is needed. It is concluded that the models help in understanding the underlying processes, but cannot yet be considered generally valid and easy-to-use software packages. In the hands of experienced geomorphologists or river engineers, however, some of the models do already form valuable tools which allow better predictions of future river planforms.  相似文献   

Seismogenic　model　of　earthquakes　in　groups　in　tectonic　block　and　analysis　for　some　features　of　earthquake　precursory　field     

张国民  耿鲁明  张永仙  石耀霖 《地震学报(英文版)》1995,8(1):1-12

Ｓｅｉｓｍｏｇｅｎｉｃｍｏｄｅｌｏｆｅａｒｔｈｑｕａｋｅｓｉｎｇｒｏｕｐｓ　ｉｎｔｅｃｔｏｎｉｃｂｌｏｃｋａｎｄａｎａｌｙｓｉｓｆｏｒｓｏｍｅｆｅａｔｕｒｅｓｏｆｅａｒｔｈｑｕａｋｅｐｒｅｃｕｒｓｏｒｙｆｉｅｌｄＧｕｏ－ＭｉｎＺＨＡＮＧ；Ｌｕ－Ｍｉｎ...  相似文献   

房山花岗闪长岩体长石斑晶的数学特征及相带划分     

胡旺亮  池顺都  周宗桂  岑博雄  伍刚  刘平 《地球科学》1987,(2)

对北京房山花岗闪长岩体中长石斑晶进行了系统测量,测点密度平均4.37个/km~2,测量标志为长石斑晶长轴长度和长石斑晶线含量等。对测得数据进行了分布统计、有序样品最优分割、和趋势变化分析等处理。揭示了长石斑晶在岩体中的分布规律和数学特征,划分了趋势岩相带,从而提出了较为合理的岩相带划分原则。  相似文献   

锡矿体变化特征及其勘探意义     

魏民  赵鹏大 《地球科学》1987,(4)

本文通过勘探变量的统计得分法以及聚类和特征分析法,将矿体变化性按成因分为四类.按不同的取样观测方法,将矿体变化性分为群体的、单体的和局部的三类,并以实例说明上述分类在矿体预测和勘探中的实际应用.  相似文献   

地球数字产品的空间数学基础   总被引：4，自引：0，他引：4  

胡鹏胡毓钜  吴艳兰杨传勇 李国建 《地球信息科学学报》2001,3(3):36-42

在分析当前地球数字产品空间数学基础局限性的基础上,将地图投影概念由传统的曲面到平面的变换扩展为曲面到曲面的变换,提出一套适合于大型GIS和地球数字产品的“地图投影”模型的实用模型,该模型的视图采用等距离切圆柱投影,度量空间是椭球面几何系统,符合计算机环境下GIS视图与度量空间分离的特性。鉴于全球多分辨率连续可视化,精密可视化量算,三维、多维地球数据统一,标准的空间定位框架和只有在统一的空间系统内全球资源、生态环境数据才能进行精确的地理分析等四个方面的需要,从地图投影进到本模型将是方向和技术趋势。  相似文献   

陕川丁家林-太阳坪金矿床黄铁矿标型特征          下载免费PDF全文

刘爽  刘新会  魏宽义 《地质找矿论丛》2005,20(Z1):20-23

金矿床中黄铁矿的化学元素、晶体形态、粒度等标型特征与其形成的物理化学环境及介质条件密切相关.通过对陕川丁家林-太阳坪金矿区主要载金矿物黄铁矿在韧性剪切变形-构造分异热液期与脆性剪切变形-构造分异热液期化学元素含量对比,以及黄铁矿形态、粒度分析,研究黄铁矿与金矿物关系.丁家林-太阳坪金矿黄铁矿形态以{100}、{210}单晶及{100} {210}聚晶为其标型.黄铁矿在空间分布特征来看,深部成矿的可能性不大.应沿丁家林-太阳坪脆-韧性剪切带寻找金矿.  相似文献   

Bedform morphology of salmon spawning areas in a large gravel-bed river     

Timothy P. Hanrahan   《Geomorphology》2007,86(3-4):529-536

While the importance of river channel morphology to salmon spawning habitat is increasingly recognized, quantitative measures of the relationships between channel morphology and habitat use are lacking. Such quantitative measures are necessary as management and regulatory agencies within the Pacific Northwest region of the USA, and elsewhere, seek to quantify potential spawning habitat and develop recovery goals for declining salmon populations. The objective of this study was to determine if fall Chinook salmon (Oncorhynchus tshawytscha) spawning areas in the Snake River, Idaho, USA, were correlated with specific bedform types at the pool–riffle scale. A bedform differencing technique was used to objectively quantify the longitudinal riverbed profile into four distinct pool–riffle units that were independent of discharge. The vertical location of thalweg points within these units was quantified with a riffle proximity index. Chinook salmon spawning areas were mapped and correlated with the pool–riffle units through the use of cross-tabulation tables. The results indicate that 84% of fall Chinook salmon spawning areas were correlated with riffles (χ² = 57.5, df = 3, p < 0.001), with 53% of those areas located on the upstream side of riffle crests. The majority of Snake River fall Chinook salmon spawning occurred at elevations greater than 80% of the difference in elevation between the nearest riffle crest and pool bottom. The analyses of bedform morphology will assist regional fish managers in quantifying existing and potential fall Chinook salmon spawning habitat, and will provide a quantitative framework for evaluating general ecological implications of channel morphology in large gravel-bed rivers.  相似文献   

Morphology of step-pools in a wilderness headwater stream: The importance of standardizing geomorphic measurements   总被引：1，自引：0，他引：1  

Aaron Nickolotsky  Robert T. Pavlowsky   《Geomorphology》2007,83(3-4):294

The morphology of step-pools and cascades reflect the geological and climatic factors affecting channels in mountain watersheds. This study uses longitudinal and cross-section surveys to describe a headwater stream in the Boston Mountains of the Ozarks Plateau region in Arkansas and develop morphological relationships for comparisons with other regions. In the Bowers Hollow Creek watershed (3.5 km²), located within the boundaries of the Upper Buffalo Wilderness Area, step height and wavelength relationships are generally similar to those reported from other regions. Step-pool reaches were widely distributed in a discontinuous manner throughout the watershed. Average values of the sampled reaches are: reach slopes, 0.105 m/m; width, 6.10 m; crest particle sizes, 440 mm; step heights, 0.87 m; and step wavelengths, 6.62 m. The mean step steepness for the watershed was 0.13, whereas the mean length of a reach step to height ratio was 9:1. A comparison of morphological definitions found that the values of step height and steepness can vary by > 30% according to how step parameters are defined. Step height is particularly sensitive; thus, comparison of step height-based relationships from published data requires great care.  相似文献