吉林桦甸地区太古宙麻粒岩变质作用的PT_t轨迹

The Metamorphic PTt Path of Archean Granulites in Huadian Area,JIlin Province

本区太古代的表壳岩系（基性麻粒岩及富铝片麻岩等）经历了麻粒岩相变质作用，根据矿物共生组合及其转化关系可将形成麻粒岩的变质作用划分为早期角闪岩相阶段（Ｔ＝５７５－６００℃，Ｐ＝０．５９ＧＰａ）、峰期麻粒岩相阶段（Ｔ＝８３５℃，Ｐ＝０．８５ＧＰａ）和晚期角闪岩相阶段（Ｔ＝６２０℃，Ｐ＝０．７０ＧＰａ），其ＰＴ＿ｔ轨迹为逆时针方向。峰期升温升压过程及晚期近等压冷却过程与ＩＢＣ型ＰＴ＿ｔ轨迹相似，反映其形成于岛弧或大陆边缘构造环境。

The Supercrust rocks such as basic granulites and alumimium-rich gnei-sses located in Huadian area,Jilin.Province,have undergone the granulite facies metamorpism.According to associations and transformation relations of minerals,metamorphism of granulites can be divided into three stages,i.c.,the early amphibolote facies metamorphic stage(T=0.5 -600℃,P=0.59 Gpa),the pcak granulite faeies metamorphic stage(T=835℃,P=0.85Gpa),ard the late amphibolite facies metamorphic stage(T=620℃,P=0.7 Gpa),which make up an anticlockwise PTt path .The IBC path suggests that these metamorphic rocks werw formed in island arc or active epicontinental enviro-nments.