柴达木盆地北缘早古生代高压——超高压变质带中发现典型超高压矿物——柯石英

从都兰北带榴辉岩的片麻岩围岩的锆石中发现了柯石英包裹体和石墨包裹体，说明该超高压带的峰期变质作用已达柯石英稳定区间（＞2.8GPa）但小于金刚石的稳定区间（＜3.5GPa），从而确定柴达木盆地北缘存在早古生代超高压变质作用和陆－陆碰撞作用，为中国中部存在一条横贯东西的早古生代（大致500－400Ma）高压超高压变质带的推断提供了新的关键性证据。

Discovery of Coesite in the North Qaidam Early Paleozoic Ultrahigh-high Pressure (UHP-HP) Metamorphic Belt, NW China

Coesite was discovered as inclusions in zircon separates from gneiss associated with a large eclogite body in the North Belt of the Qaidam UHP terrane. Some graphite inclusions also found. This finding confirms our previous suggestion that the North Qaidam UHP terrane was recrystallized at p below the diamond stability field based on several lines of evidence such as polycrystalline K-feldspar and quartz inclusions in eclogitic garnet, quartz lamellae in omphacite and p-t estimates for both eclogite and garnet peridotite. The occurrence of coesite inclusions in zircon suggests in-situ UHP metamorphism. This UHP terrane, along with the Altun e-clogite of 504 Ma, and those to the east of Qilian Mts, in the North Qingling, Tongbai and North Dabie regions, recorded the Early Paleozoic collision between the Sino-Korean and Yangtze plates. This UHP belt could extend to further west to the similar age Kokchetav UHP belt in Kazakastan.