秦岭-大别造山带地壳化学结构研究

Research of continental crust chemi cal texture of Qinling-Dabie orogenic belt

大陆地壳不同结构层之间化学组成(含元素和同位素组成)的系统性差异可以称为地壳化学结构,地球化学参考模型(GERM)能够作为参照标准进行地壳化学结构(元素组成)的对比分析,据此提出了反映地壳演化特征的蛛网图标准化方法。对秦岭-大别造山带的尝试发现,造山带总体上具有物质组成分异较弱的特点;造山带及邻区太古宙结晶基底太华群、崆岭群的化学组成都不能代表全部的下地壳,可能仅代表了下地壳上部,而大别群可能经历了复杂的构造熟化过程。通过对造山带地壳化学结构的分析,指出铕负异常可能并非为地壳拆沉作用所造成。

The systemic chemical composition d ifference among continental crust t exture layers can be called crust chemical texture.Geochemical Earth Reference Model(GERM)provides a standard for chemical texture compar-ison,and the spider diagrams are put forward to analyze the continental c rust evolution.Through the researc h of Qinling-Dabie orogenic belt,it can be found that crustal differentiati on of the orogenic belt is weak.Taihu a Group and Kongling Group,the basements of the adjacent zones,can only represe nt the upper lower crust,while the Dabie Group,basement of the South Qi ning orogenic belt,may have experie nced complex structural maturation process.Analysis of continental crust implies that the europium anomaly may not be the result of crust delami na-tion.