陆-陆碰撞造山带中压型变质作用的pT轨迹——以南秦岭佛坪地区为例

pT path of medium-pressure metamorphism of continental collision orogenic belt -exemplified by the southern Qinling orogenic belt

依据石榴石的环带特征反演了南秦岭造山带中压型变质作用的 pT轨迹 ,表明石榴石的环带记录了峰期变质前的温压条件递增过程 ,其最高温度与最大压力一致 ,这一过程可能与地壳的持续加厚过程相对应。峰期变质以后即出现有构造作用参与的快速抬升过程 ,pT轨迹表现为ITD型。这一研究可以加深人们对造山带发生中压型变质作用过程的理解。

On the basis of garnet zonation, a pT path is inversely modeled for medium_pressure metamorphism of the southern Qinling orogenic belt. The path indicates that the garnet zonation recorded the pT increasing process before the metamorphic peak, and that the maximum temperature was coincident with the maximum pressure in the process, probably corresponding to a continuous crustal thickening process. Following the metamorphic peak, a rapid uplift accompanied by tectonic processes took place, resulting in a pT path of ITD type. The present study is helpful to understanding the medium_pressure metamorphic process of the continental collision orogenic belt.