【摘要】 尺度依赖性存在于各种复杂而漫长的地质现象或过程中,作为地学研究对象的环形构造必然存在尺度效应,其空间特性在不同尺度下差异显著。环形构造的定量分析需要在特定的空间尺度下才能开展,合理尺度的选取则是对其进行定量分析的基础。以云南会泽东部地区为研究区,利用表征线性构造对称信息的中心对称度对环形构造展开研究。首先,在GIS的支持下对在OLI影像上提取的遥感线性构造进行5次采样,采样网格的尺度分别为5.0,3.6,2.5,1.8,0.7 km;其次,运用多元回归方程+残差和趋势面拟合的方法分析中心对称度的尺度特征,并且结合遥感图像上的可识别信息判定3.6 km为该区域环形构造研究的最优尺度;最后将最优网格尺度下的中心对称度与密度、强度和信息熵进行因子分析,提取的Z1代表高破碎中心对称度,可用于寻找与岩浆入侵有关的放射状、环状隐伏断裂系统;而Z3代表低破碎中心对称度,其空间特征与牛栏江演化过程中形成的环形地貌相吻合。研究结果表明,通过对中心对称度的尺度效应分析选取最优尺度并解译出具有实际地质意义的环形构造是可行的。更多还原

【Abstract】 Scale dependence exists in a variety of complex and lengthy geological phenomena or processes,as the object of geological research.The circular structure is bound to scale effect and its spatial characteristics are significantly different at different scales.Quantitative analysis for circular structure needs to be employed on specific spatial scale,while the selection of reasonable scale is the basis of quantitative analysis.In this paper we took the eastern area of Huize in Yunnan as the research area,then studied the circular structure by using the central symmetry which represents the symmetry information of the lineaments. Firstly, the remote sensing(RS) lineaments extracted from OLI images were sampled for 5 times with grid of 5.0, 3.6, 2.5, 1.8 km and 0.7 km respectively under the support of GIS. Secondly, the method of multiple regression equation+residues and trend surface fitting was used to analyze the scale characteristics of central symmetry of lineaments. Combining with the identifiable information of RS image, we suggest that 3.6 km is the optimal scale for the study of circular structure in this region.Finally,factor analysis was performed with central symmetry, density, intensity and information entropy on the optimal grid scale.Then,Z1 representing central symmetry with high fragmentation was used to search the radial and annular concealed fault system related to magma intrusion, while Z3 representing central symmetry with low fragmentation was in correspondence with the annular landform formed during the evolution process of Niulan River. The results show that it is feasible to select the optimal scale and interpret the circular structure with practical geological significance by analyzing the scale effect of central symmetry.更多还原