retrogressive metamorphism

The petrographical data of the deep seated xenoliths indicate that they could be subjected to earlier eclogite facies high pressure ( HP ) and ultra high pressure metamorphism ( UHPM ) and late amphibolite facies retrogressive metamorphism , then caught by the host magma .

深源捕虏体的岩相学研究表明，它们经历了早期的榴辉岩相变质和晚期的角闪岩相退化变质，然后被寄主岩浆所捕获。

The eclogite remains well its original characteristics , which has only suffered slight retrogressive metamorphism .

榴辉岩原始特征保存完好，仅遭受轻微的退变质作用和叠加变质作用。

The p-T path of retrogressive metamorphism is also discussed in this paper .

文中还对退变质过程中的p-T轨迹作了讨论。

Retrogressive Metamorphism of Archaean Granulites and the Evidence of Rb-Sr Isochron Age in Zhangjiakou and Xuanhua Regions

张家口宣化地区太古代麻粒岩退变质作用与RbSr等时年龄证据

The study shows that they have all experienced the same epidote amphibolite facies metamorphism although their peak metamorphic conditions are different . Their peak metamorphic ages are very close and they have similar retrogressive metamorphism paths .

研究发现，尽管它们有着不同的峰变质条件，但都经历了相同的绿帘角闪岩相前进变质，具有相近的峰变质年龄和相似的退变质轨迹。

The granulite facies were resulted from the regional high-temperature metamorphism with medium pressure . The metamorphism evolution was the retrogressive metamorphism with approximate isobaric cooling ( IBC ) and counter clockwise PTt path .

麻粒岩相是中压区域高温变质作用的产物，变质作用的演化为退变质、近等压冷却（IBC）反时针型的PTt轨迹。

Fresh eclogite yields the biggest compressional wave velocity ( 7 . 86km / s ) , and gneiss has smaller velocity ( 5 . 53 - 5 . 71km / s ) . Seismic velocity of eclogite significantly decreases with increase of retrogressive metamorphism .

主孔中新鲜榴辉岩纵波速度（Vp）最大（7.86km/s），正副片麻岩波速最小，又分别为5.53km/s和5.71km/s，榴辉岩的波速随着退变质作用的增强而明显减小。

Seventeen zircon U-Pb concordant ages ( from 858 to 778 Ma ) show the time of amphibolite-facies retrogressive metamorphism of the Panxi granulites . Amphibolite-facies retrograde metamorphism took place during rapid cooling and uplift of the Panxi granulite , which was probably correlated with the Neoproterozoic mantle plume activities .

17件锆石U-Pb的谐和年龄（858-778Ma）可能是麻粒岩受新元古代地幔柱活动影响，在快速冷却和抬升过程中发生角闪岩相退变质作用的时代。