变质橄榄岩中尖晶石的分形结构因子类型及其成因意义

利用沈步明（１９９３）提出的分形结构因子的新方法，计算了橄榄岩包体、方辉橄榄岩、纯橄榄岩和铬铁矿等六种尖晶石的分形结构因子。划分了四种尖晶石分形结构因子类型：Ａ１和Ｃｒ强变异型、Ａ１和Ｃｒ变异型、Ｍｇ和Ｆｅ２－变异型、Ｍｇ和Ｆｅ２－强变异型，结合尖晶石的地质产状讨论了这四种类型的成因意义。通过大量分形结构子的计算和图表．有力说明分形结构因子对于表征物质在空间分布的结构性和数据之间的相关性，是一种有效的定量化手段。在推测尖晶石和主岩的成因方面，尖晶石的Ｃｒ（Ａ１）和Ｍｇ（Ｆｅ２＋）的ＦＳＦ值图解更优于尖晶石的Ｃｒ／（Ｃｒ＋Ａ１）－Ｍｇ／（Ｍ＋Ｆｅ２－）图解。

THE TYPE OF FRACTAL STRUCTURE FACTOR FOR SPINEL FROM METAPERIDOTITE AND ITS SIGNIFICANCE

The fractal structure factors (FSF ) of spinel from ultramafic xenolith, harzburgite,dunite and chromite have been calculated using a new method presented by Shen (1993).Four kinds of type and its significance for fractal structure factor of spinel also have been studied, and the four kinds of type are:(1)very strong variety of Al and Cr:(2) strong variety of Al and Cr; (3) strong variety of Mg and Fe2-;(4) very strong variety of Mg and Fe2 . It is shown by a lot of table and figure that the fractal structure factor is a strong approach to express the structurization of space distribution of matter and interrelation betweendata. The FSF(A1, Cr) versus FSF (Mg, Fe2- ) diagram is better than Cr/(Cr A1) versus Mg/(Mg Fe2 )diagram to presume the cause of formation of spinel and original rock.