华中高压－超高压变质富铝岩石的温压条件研究及其地质意义

p-T CONDITIONS AND GEOLOGICAL SIGNIFICANCE OFAl-RICH ROCKS FOR HIGH AND ULTRA-HIGH PRESSURE METAMORPHISM IN CENTRAL CHINA

华中高压－超高压变质富铝岩石为陆壳岩石经变质而成，其典型的岩石类型为蓝晶石黄玉石英岩。矿物温压计估算其ｐ－Ｔ条件为Ｔ＝７００℃，ｐ＝１．２ＧＰａ；高温高压实验结果表明，蓝晶石＋黄玉组合在Ｔ＝１０００～１２００℃，Ｐ＝３．１～３．７７ＧＰａ范围内可以稳定存在，是高压－超高压变质作用产物。在蓝晶石石英岩中发现柯石英及柯石英假象，区域上其它岩石组合也有高压－超高压变质作用的证据。变质富铝岩石为榴辉岩相变质作用产物，从而证明陆壳岩石可以经历＞２．０ＧＰａ的变质压力条件。

The-rich rocks for high and ultra-high pressure metamorphism in Central China are metamorphic continental crust rocks. The kyanite-topaz quartzites are the typical types, The p- T condition given by mineralogc thermometer and pressure gauge is 700℃ and 1.2 GPa, The results of high temperatureand high pressure experiments suggest that the assemblage of kyanite+topaz exists staby in a range of T=1000～1200℃ and p=3.1～3.77 GPa,It is the product of high and ulta-high pressure metamorphism. The coesite relicts and pseudomorphisms are found in te kyanite quartzite in Dabie Mountain,Henan province. There are also some evidences ofhigh and ultra-high pressure metamorphism in other rock assemblage of the area.The Al-rich rocks are the products of eclogite facies metamorphism, It has been proved that the continental crust rocks can be produced in a condition above 2.0GPa.