矿化结构分析的变异椭球体构造及应用  

Construction and application of variation ellipsoid for analysis of mineralization structure

作　　者：毛先成[1] 曹芳[1] 邹艳红[1] 赵莹[1] 

机构地区：[1]中南大学有色金属成矿预测教育部重点实验室,地球科学与信息物理学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2014年第9期3076-3084,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(41172297;41102204);国家"十二五"科技支撑计划项目(2011BAB04B10)

摘　　要：针对目前矿化结构分析中变异椭球体的构造仅考虑地质体走向、倾向、垂向上矿化结构的问题,提出一种以椭球体模型为基础,以变异函数为工具,综合考虑矿体的形态产状和品位的三维空间变异特征来构造变异椭球体的新方法。该方法通过计算铅、锌品位在空间中各个方位上的实验变异函数,绘制矿体走向倾斜面上的实验变异函数等值线图,研究矿体走向倾斜面上的铅、锌品位分布,确定变异椭球体的长轴方向,进而绘制与长轴相垂直平面上的实验变异函数等值线图,确定变异椭球体的次长轴和短轴方向;然后,分别用理论模型拟合这3个方向上的实验变异函数,得到其变程作为三轴的长度。将该方法应用于青海虎头崖矿床,构造矿床铅、锌品位的变异椭球体,并将其作为搜索椭球体来限制品位插值过程中已知样品点的搜索范围。研究结果表明:采用该方法构造的变异椭球体,不仅考虑了矿体形态对矿化空间分布的影响,而且有效地反映了铅、锌品位在空间中的分布及变异情况,为隐伏矿体定量预测提供了依据。As the construction of variation ellipsoid only considered the mineralization structure in the trend, inclination, and vertical direction of geologic bodies in analysis of mineralization structure, a new method based on ellipsoid model was presented to construct variation ellipsoid by considering the shape and occurrence of ore-bodies and 3D spatial variation characteristics of ore grade comprehensively with the tool of variogram. Experimental variograms of grade variables in all directions in space were calculated and the contour map of experimental variogram on the inclined surface along the trend of ore-bodies was plotted, so grade distribution on the inclined surface along the trend of ore-bodies could be investigated and the long axis direction of variation ellipsoid was defined. Then the contour map of experimental variogram on the inclined surface perpendicular to the long axis was plotted, and so the secondary long axis direction, the short axis direction of variation ellipsoid could also be defined. Theoretical models were used to fit experimental variograms in the directions of the three axes, and their variation ranges were selected as lengths of the three axes. Finally, this method were applied in Hutouya ore deposit, Qinghai Province, and variation ellipsoids of Pb and Zn grades were constructed which were also taken as search ellipsoid to limit the search extent of known sample points in process of grade spatial interpolation. The results show that the variation ellipsoids constructed with this method not only consider the impact of the ore body morphology on mineralization spatial distribution, but also reflect spatial distribution and variability of grade variable effectively, which provides a basis for quantitative prediction of concealed ore bodies.

关 键 词：地质统计学 变异函数 变异椭球体 倾伏向 倾伏角 旋转矩阵 

分 类 号：P624[天文地球—地质矿产勘探]