大别造山带燕山期造山作用的岩浆岩石学证据

在区域地质填因基础上研究了大别地区燕山期岩浆岩，重新划分了该区燕山期岩浆作用期次，发现大别地区在燕山期存在一个完整的造山岩浆旋回。首次提出本区燕山晚期岩浆岩为双峰式组合，与燕山早期岩浆岩属高钾钙(碱)性—钾玄岩组合一起构成一个从挤压到伸展的造山岩浆旋回，成为燕山期造山的重要佐证。岩浆岩成因特点揭示出本区的岩石圈结构在燕山期存在一个从双倍陆壳到正常陆壳的过程，深部地质过程则是底侵作用和拆沉作用的继续。

Evidence of magmatic petrology for the Yanshanian orogeny in the Dabie orogen

On the basis of regional geological mapping,the authors studied Yanshanian rocks in the Dabie area,re-determined the phases of Yanshanian magmatism and fo und the existence of a complete orogenic magmatic cycle in the area.They for the first time propose that the late Yanshanian magmatic rocks in the area constitu te a bimodal association,which combines with the early Yanshanian magmatic rocks (belonging to high-K calc-alka-line-shoshonitic association)to form a compressional to extensional orogenic magmatic cycle.This is important evidence of Yanshanian orogeny.The features of origin of magmatic rocks have revealed that the lithosphere structure in the ar ea experienced a process from double continental crust to normal continental cru st in the Yan-shanian stage.The deep geological process was the continuation of underplati ng and delamination.