The Discussion Of Application Of GIS-Fractal Method In Handling Data Of Exploration Geochemistry

During the disposal of regional geochemical data, the key is confirmation of anomalous threshold, which is also a fundamental issue in explorative geochemistry. For long time, the threshold is confirmed on the assumption that the concentration of chemical elements in the crust follows a normal distribution or concentration of elements takes on a continuous change in space. However, the spatial distribution of geochemical elements is extremely complicated.Self-similarity or scale invariance is the essence of fractal that is controlled by power-law and can be described quantificationally with fractal dimension which is an eigenvalue. The concepts of fractal have been used in the non-order systems with self-similarity which exist extensively in natural phenomena and social activities. It has been shown that the quantity of geochemical fields (element concentration) is a function of temporal and spatial coordinates, moreover, spatial distribution and temporal evolvement are both of scale invariance ,that is to say, they are of fractal structure.This paper analyzes three stream sediments data sets of southeast of Henan province by use of traditional statistical methods and GIS techniques-fractal methods(concentration-area model), one of which is from Mashan in Neixiang country to Jiguanduo in Zhenping country with scale of 1:50000 (Ag, Au, Cu, Mo, Pb, Zn, 2173 grid samples), other of which is from Zhouwan to Guanfangtan in Xichuan country with scale of 1:50000 (Ag, Au, Cu, Mo, Pb , 1447 grid samples), the other of which is Nanyang district with scale of 1:200000 (Ag, Au, Cu, Pb, Zn , 11331 grid samples) where it includes the other two areas. The results show three points as follows. Firstly, it is worth applying widely to research in geochemistry, because all kinds of geochemical graphs can be made conveniently and the area which corresponds to concentration can be measured quickly by making use of the double attribute classification statistics of the space analysis sub-system with dense dataGauss distance power interpolation on MapGIS platform. Secondly, there are some elements which take on multifractal features with more than two non-scale sections, so they have more than one anomalous thresholds theoretically which can used for distinguishing anomalies gradually. Thirdly, the GIS-fractal method is of good practicality, because it not only locates accurately the target of mineralization with measuring simply but also takes on the feature of spatial distribution of geochemical data.