Material component to non-linear relation between sediment yield and drainage network development: an flume experimental study     

JIN De-sheng  CHEN Hao  GUO Qing-wu 《地理学报》2001,11(3):271-281

This paper examines the experimental study on influence of material component to nonlinear relation between sediment yield and drainage network development completed in the Lab. The area of flume drainage system is 81.2 m2, the longitudinal gradient and cross section slope are from 0.0348 to 0.0775 and from 0.0115 to 0.038, respectively. Different model materials with a medium diameter of 0.021 mm, 0.076 mm and 0.066 mm cover three experiments each. An artificial rainfall equipment is a sprinkler-system composed of 7 downward nozzles, distributed by hexagon type and a given rainfall intensity is 35.56 mm/hr.cm2. Three experiments are designed by process-response principle at the beginning the Ψ shaped small network is dug in the flume. Running time spans are 720 m, 1440 minutes and 540 minutes for Runs I, IV and VI, respectively. Three experiments show that the sediment yield processes are characterized by delaying with a vibration. During network development the energy of a drainage system is dissipated by two ways, of which one is increasing the number of channels (rill and gully), and the other one is enlarging the channel length. The fractal dimension of a drainage network is exactly an index of energy dissipation of a drainage morphological system. Change of this index with time is an unsymmetrical concave curve. Comparison of three experiments explains that the vibration and the delaying ratio of sediment yield processes increase with material coarsening, while the number of channel decreases. The length of channel enlarges with material fining. There exists non-linear relationship between fractal dimension and sediment yield with an unsymmetrical hyperbolic curve. The absolute value of delaying ratio of the curve  相似文献   

丰城三溪峡——东乡石马岭推覆构造是扬子板块与华南板块的直接分界线   总被引：5，自引：0，他引：5  

朱旗展  万浩章 《江西地质》2001,15(4):241-246

扬子板块与华南板以丰城三溪峡－东乡石马岭推覆构造分野。该推覆构造发育在萍乡－广丰深断裂与遂川－德兴深断裂的复合部位，具有可行－逆冲推覆性质。原地系统为扬子地层分区中元古界牛头岭组、高桥组和将军岭组，外来系统是华南地层分区新元古界源里组，分别相当于蓟县系修水组和青白口系上施组同期沉积。根据推覆变形形式、构造岩特征和变形程度，可将推覆体划分为包括糜棱岩亚带、糜棱岩化亚带在内的变形主带和劈理化带。韧性剪切变形与推覆变形同期产生，但影响范围更广泛。  相似文献   

川东地区碳酸盐岩超压与天然气富集关系研究   总被引：7，自引：2，他引：7  

李仲东 《矿物岩石》2001,21(4):53-58

地层流体超压的形成、演化及分布与油气成藏的主要石油地质过程有着千丝万缕地联系。由于碳酸盐岩本身的复杂性，其超压的成因及研究方法不能简单地借用“欠压实”的原理。本文从对比砂泥岩和碳酸盐岩在成压机理上的差异性入手，详细探讨了川东地区碳酸盐岩成压的各种机理，指出成烃作用是造成区域性超压的最主要因素；并结合该区超压平面上的分区性及纵向上的分带性，论述了各区、带超压与气藏分布的内在联系，总结出该区超压与天然气富集的关系。  相似文献   

一类反演公式     

姚红 《测绘学院学报》1996,(3)

本文讨论的是组合数学中的级数反演公式，作者利用Ｂｅｌｌ多项式给出了一类很广泛的反演公式，并通过实例说明许多反演公式都是这一类反演公式的特例。  相似文献   

Asymmetric fuzzy relation analysis method for ranking geoscience variables   总被引：1，自引：0，他引：1  

Qiuming Cheng 《Natural Resources Research》1996,5(3):169-180

A fuzzy relation analysis method is used to derive weights for qualitative variables based on their partial order relations. Two asymmetric measure indexes (incidence coefficient and probability difference) are proposed to measure the asymmetric associations between geoscience variables from which the partial order relations can be constructed. The fuzzy relation analysis method can be implemented in combination with the asymmetric measure indexes leading to new methods for pattern overlay and data integration in mineral potential prediction. Two types of models are proposed and illustrated by two artificial examples: one for predicting targets for undiscovered deposits, and the other for estimating the mineral resource potential of the targets.  相似文献   

蒲江—新津—成都—德阳断裂带——成都平原内一条代表性弱活动地震带的地震地质特征     

钱洪  唐荣昌  马声浩 《四川地震》1992,(4)

活断层是地震的潜在策源地。然而不同的活断层上地震潜在能力有极大的差别。客观地评价活断层上地震潜在能力不仅是地震预报研究的需要,对国民经济建设的布局和抗震决策也极为重要。在这个意义上,对弱活动性断裂的研究与对强活动性断裂的研究具有同样的重要性。本文以弱活动的蒲江—新津—成都—德阳断裂带为例,讨论了该断裂的晚第四纪活动性,断裂带的地质结构以及断裂的切割深度等因素对该断裂带地震潜在能力的可能影响。  相似文献   

模糊聚类分析及其地质应用实例     

唐淑贤 《湖南地质》1992,11(2):163-168

摘要聚类分析直接利用相似矩阵或相关矩阵来分类,但它们本身存在矛盾,分类时也会出现矛盾。为消除这个矛盾,可采用模糊聚类分析。它的特点是,通过相似矩阵连续自乘,改造成模糊分类矩阵,随后按不同要求进行分类。本文旨在介绍模糊聚类分析的步骤和方法,并提供一个PC—1500袖珍机模糊聚类分析源程序。附两个算例。  相似文献   

黄河下游的河性   总被引：8，自引：0，他引：8  

尹学良  陈金荣 《地理学报》1992,47(3):193-207

本文探讨了黄河一般特性的综合关系,讨论了河道演变中均衡与非均衡的问题、滩槽冲淤的利与害和主与从的问题,同时讨论了河道冲淤演变特性、与水沙条件的关系、河槽淤积率和淤积比等。  相似文献   

The perimeter-area fractal model and its application to geology   总被引：14，自引：0，他引：14  

Qiuming Cheng 《Mathematical Geology》1995,27(1):69-82

Perimeters and areas of similarly shaped fractal geometries in two-dimensional space are related to one another by power-law relationships. The exponents obtained from these power laws are associated with, but do not necessarily provide, unbiased estimates of the fractal dimensions of the perimeters and areas. The exponent (D_AL) obtained from perimeter-area analysis can be used only as a reliable estimate of the dimension of the perimeter (D_L) if the dimension of the measured area is D_A=2. If D_A<2, then the exponent D_AL=2D_L/D_A>D_L. Similar relations hold true for area and volumes of three-dimensional fractal geometries. The newly derived results are used for characterizing Au associated alteration zones in porphyry systems in the Mitchell-Sulphurets mineral district, northwestern British Columbia.  相似文献   

Moment tensors of earthquakes in and near the Tibetan Plateau and their scaling law     

Si-Hua Zheng  Ziro Suzuki 《地震学报(英文版)》1993,6(2):365-377

Moment tensors of eleven major earthquakes in the Tibetan Plateau and its surrounding region from 1966 to 1980 are estimated by generalized inverse technique. The seismic source time function and focal depth are immediately determined in the inversion. The results show that moment tensors of some events differ significantly from double couple, the deviation increases with decreasing plunge angle of null axis. All these events occurred in the upper crust, much shallower than those reported so far, for example, in NEIS Bulletin. Focal mechanism solution obtained from the moment tensors are consistent with the idea that the Indian plate collides northwards with the Eurasian plate and that an eastward spreading exists in the crust of the Tibetan Plateau. The stress drops for earthquakes of intraplate are systematically higher than those of earthquakes in suture zone. The source process duration becomes longer with seismic moment, but for the same seismic moment, the process duration for earthquakes in suture zone is about 1.4 times of those for intraplate event, these results suggest that the earthquakes near suture zone may be of a special characteristics in source process differently from those in intraplate. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 423 – 434, 1992.  相似文献