Fractal identification of mineralization intensity in Dayingezhuang gold deposit, Jiaodong Peninsula, China

Quantitative estimation of mineralizing intensity in different parts of Dayingezhuang gold ore deposit in Jiaodong Peninsula is carried out using both the Hurst exponent of self-affine sets and the dimension in self-similar sets. The results show that Hurst exponents of non-mineralized areas ranges from 0.89 to 0.92 and the dimensions in self-similar sets varies from 2.21 to 2.37; Whereas, the Hurst exponent and the dimension in self-similar set in the mineralized area ranges from 0.42 to 0.85 and 0.61 to 1.61 respectively. In general, the Hurst exponent in self-affine set and dimension in self-similar set are positive correlated, and the correlation coefficient is 0.80; moreover, in the places where the dimension in self-similar set and Hurst exponent are relatively small, the mineralization is more pronounced, and vice versa; in addition, when the dimensions in self-similar sets are similar, the greater the Hurst exponent means the thicker the orebody. The combination of the Hurst exponent and the fractal dimension is the statistically effective index indicating the mineralization intensity. There are obvious differences between mineralized areas and non-mineralized areas, and there also exist differences between intensely mineralized areas and weakly mineralized areas. The correlation of two parameters is resulted from the connection between their calculation methods. Mineralization intensity is one of the key problems in the study of ore deposit. Isotopes and fluid components data acquired by geochemical testing contain abundant information about metallogeny, material sources etc., but their instructions for mineralization intensities of certain areas are still ambiguous, and geology observations are also difficult to identify the mineralization intensity. Element grade is still a key indicator of mineralization intensity, and geo-mathematics theory becomes an effective tool to quantitatively estimate the mineralization intensity. Fractal theory is an important way for studying element grade distribution, which includes self-similar fractal and self-affine fractal. (Cheng, 1999a, 1999b; Deng et al., 2001) The former is brought into wide use, while the latter is relatively much less utilized; and the internal relationship between the two fractals in describing grade distributions is rarely investigated at present. (Mandelbort, 1985; Xie, 1997) This paper takes the Dayingezhuang gold ore deposit as an example, analyzes the mineralization intensity in different areas using both the Hurst exponent of self-affine sets and the dimension D in self-similar set, and also illuminates the connection in the calculation process between the two fractal indexes.