两种容量维方法提取化探数据异常下限效果对比

Comparison of lower limit value determined by two fractal methods

对云南某地1 850个(其中11个点水域覆盖,以0代替)水系沉积物Au元素化探数据进行含量-求和法与含量-数目法分维值计算,均表明Au含量数据存在两个无标度区,反映研究区Au元素存在两个不同层次的分布,即背景场和异常场。两者所确定的异常下限相同,但前者分维值(3.299 9和0.083 1)均大于后者分维值(2.679 2和0.013 5)。依据异常下限将异常场分解出来。Au元素异常场三维曲面图与原始数据综合场三维曲面图对比,不仅保留基本异常信息,并且突出弱异常信息,反映弱异常区不同矿化中心的叠加。Au元素背景场与异常场均存在聚集与分散双重性质。背景区金元素分布整体分散连续,局部微弱聚集,异常区整体高度聚集,局部分散连续。

1 850 Au grade data from Yunnan are analyzed by two fractal methods. Both grade-sum and gradenumber methods show that Au grade data have two different Multi-fractal Scaling range. Lower limit values determined by both are identical, though the former tow fractal values（0. 454 and 0.872）are lower than the latter（ 1. 973 and 1. 121 ）. Three dimensional curved face result from background removed data show more week anomalies than that of result from primitive data, while show the same strong anomalies with the later. Both background field and anomaly field show double property of concentration and dispersion. Gold concentration in background field is dispersion in integrality while week concentration locally. Gold concentration in anomaly field is high concentration in integrality while locally dispersion and continuous.