超高压变质作用:地球科学的新热点

Ultrahigh-Pressure Metamorphism:A New Hot-Spot in Earth Science

超高压变质作用是变质压力达2.5Gpa以上的超深变质作用。以出现柯石英、金刚石等超高压变质矿物为标志。我国大别苏鲁是世界上出露最好、延伸最长的超高压变质带。代表中晚三叠纪扬子陆块向中朝陆块深俯冲过程中巨量陆壳物质曾经进入地幔深度达150km。超高压变质的形成和折返、隆升岩石记录的精细研究,可以获得变质的PT轨迹,进而重塑"先挤压、后拉张"的构造演化模型。超高压变质作用的研究为板块构造理论在大陆的应用,展开新前景,已经成为地球科学的新热点之一。

Ultrahigh-pressure （UHP） metamorphism refers to those of which metamorphic pressure is higher than 2.5Gpa because of ultradeep conditions. Coesite , metamorphic diamond and other UHP mineral or mineral assemblages typify their collisional origin. In China, Dabie-Sulu collisional orogenic belt developes the most well-exposed and largest in scale UHP metamorphic belt in the world. The development of the UHP metamorphic belt indicates that in the mid-Triassic time the Yangtze craton was deeply subducted beneath the Sino-Korea craton implying that voluminous crustal materials have been deeply subducted to a mantle-depth up to 150 km. The careful study of those petrological records remained in the UHP metamorphic rocks reveals their formation, uplift and exhu- mation processes. From these information the metamorphic PT path and an＂active compression and then active extension＂ 4-stage tectonic evolution model can be reconstructed. Therefore, the study of UHP metamorphism had provided new prospects for the theory beyond plate tectonics onward the continents. UHP metamorphic study had become a new hot-spot in the field of Earth science.