鄂东北大别杂岩中混合岩形成的动力学机制

DYNAMIC MECHANISM OF MIGMATIZATION IN DABIE COMPLEX, NORTHEASTERN HUBEI, CHINA

作者在详细野外工作的基础上,采用斜长石和钾长石成分及含量,有序度测定,斜长石延性系数的统计,质量平衡计算,矿物空间分布和地球化学研究表明,本区混合岩具有热中心,从中心往外,混合岩的矿物性质有规律地变化。主导成因机制是深熔和交代;而且,从中心向外,深熔和交代的强度逐渐臧弱。最后,以Liesegang环形成的实验结果作类比,从非线性动力学(耗散结构理论)的角度,深刻揭示了本区混合岩形成的动力学机制即热异常诱导早期交代,交代诱导重熔,最后是重熔期后的交代。

On the basis of the detailed field work, compositions and contents of plagioclase and K-feldspar, determination of ordering degree, statistical analysis of plagioclase elongation index, mass-balance calculation and studies of mineral spatial distribution and geochemistry, it is concluded that the migmatites in the Dabie complex are characterized by thermocenters in their spatial distribution. There are regular changes in mineral characters in migmatites from the centers outwards. The dominant genetic mechanism is anatexis and metasomatism, and from the centers outwards the intensities of anatexis and metasomatism are gradually reduced. Finally, according to the simulated experiment on Liesegang's rings and non-linear dynamics (dissipative structure theory), the dynamic mechanism of migmatization is expounded profoundly, that is, the early-stage metasomatism induced by the thermal anomaly, the cardinal stage anatexis induced by the earlystage metasomatism and finally the last stage metasomatism post-anatexis.