MF-DFA方法与成矿元素分布特征——以大尹格庄金矿为例

Method of MF-DFA and distribution characteristics of metallogenic elements: example from the Dayin′gezhuang gold deposit,China

在采用Jarque-Bera统计量和Augmented Dickey-Fuller检验法,分别进行正态和稳定性检验的基础上,运用多重分形消除趋势波动分析方法(MF-DFA)和多重分形谱分析方法,研究了山东大尹格庄金矿-290m中段多钻孔Au元素的长程相关性和多重分形特征,并分析多重分形谱曲线的宽度差异和对称性.结果显示:消除二阶多项式非线性趋势后,趋势波动函数Fq(s)与尺度s具有较好幂律关系,广义Hurst指数h(q)是随q的非线性函数,h(2)值均小于1但大于0.5,即具有长程相关性,表明在特定的地质背景下该矿体的发育相对稳定,其与大尹格庄金矿的地质事实相吻合.多重分形谱曲线为非对称状且各有不同,表明该地区的Au元素品位序列具有明显多重分形特征,其多重分形谱函数的形态差异为矿化强度的识别提供依据,从而可为进一步判定矿床富集程度、圈定有利成矿靶区提供指导.

Based on the tests of normality and stability respectively by Jarque-Bera statistics and Augmented Dickey-Fuller test, the methods of multifractal detrended fluctuation analysis（MFDFA）and multifractal spectrum analysis were applied to study the long-range correlations and multifractal characteristics of Au in the drifts on -290 m level of Dayingezhuang gold ore deposit in Shandong province, China. The width difference and asymmetry of multifractal spectrum were also analyzed. The results show that after elimination of a number of second-order non-linear trends, the detrended fluctuation function Fq （s） has a good power-law relation with scale s, the generalized Hurst exponent is a nonlinear function respect to q, and all the values of h（2） is less than 1 but greater than 0.5, which indicates the long-range correlation, andmeans the development of the orebodies is relatively stable under the specific geologic back- ground and consistent with the facts in Dayin＇gezhuang gold ore deposit. The results also show that the multifractal singular spectrum curves of the drifts are non-symmetrical and differ from each other, which indicates the grade series of Au in the region is characterized by multifraetal features, while the shape differences of multifraetal spectrum may offer an evidence for the i- dentification of mineralization intensity, and provide guidance for further determination of the extent of deposit concentration and delineation of a target mineralization zone spectrum.