断裂分维值对矿产资源预测的指示意义—— 以西藏地区为例

SIGNIFICANCE OF DIMENSION VALUE D OF FAULT SYSTEMS IN EVALUATING NATURAL RESOURCES WITH TIBET AS AN EXAMPLE

应用分形几何的原理，采用数盒维法计算了西藏地区（Ｄ＝１７８４）及其内部羌塘（Ｄ＝１２１７）、比如盆地西部（Ｄ＝１２２７）、措勤（Ｄ＝１２９７）三个油气勘探区和三江金属矿产勘探区（Ｄ＝１８２０）的断裂分维值。分别与四川盆地含油气区、江西德兴和湘中金属矿产区的断裂分维值比较，发现含油气区的断裂分维值大致介于１＜Ｄ＜１２４，明显低于整个区域断裂分维值，Ｄ值越小，越有利于油气成藏；金属矿产区Ｄ＞１．８０左右，大于整个区域分维质，Ｄ值越大，矿床规模越大。此预测了羌塘、比如盆地西部具备含油气区的构造条件，三江地区的构造情况利于形成大规模金属矿床。

The principles of fractal geometry and method of box counting dimension have been used to calculate the fractal dimension value D of fault systems in three oil gas prospecting areas (Qiangtang, Biru, Cuoqin) and an ore deposit prospecting area (Sanjiang) in the Tibet region. The values were then compared with those of the oil gas areas in Sichuan, ore-deposit areas in Dexin, Jiangxi province and in central Hunan province respectively It has been found that the dimension of fault systems in the oil gas bearing areas is 1< D <1 24 approximately, smaller than the dimension of whole region The small dimension is in favor of the formation and preservation of oil gas deposits The dimension of fault systems in the ore deposit area is about D >1 80, lager than that of the whole region. The larger the dimension, the larger the scale of ore deposit The results of this study suggest that it is hopeful to find certain oil gas fields in the Qiangtang and Biru prospecting areas, and high grade ore deposit in the Sanjiang prospecting area