摘要
据静水压力梯度计算 ,榴辉岩形成深度至少要 70km ,含柯石英榴辉岩的形成深度至少要 12 0km ,而同时含有柯石英和金刚石的榴辉岩形成深度至少要 145km ,超高压变质岩要从如此深的部位折返到地表是不可想象的 .大量资料表明水参与了超高压变质作用过程 .通过矿物的脱水行为、水的相变和地温曲线等研究 ,指出由于存在水的相变增压等多种增压因素 ,大大提高了超高压变质作用过程中的地压梯度 ,据静水压力计算出的超高压变质岩形成深度只是最大深度 ,其形成时的实际深度要比该最大深度小得多 .
The calculation in the hydrostatic pressure gradient shows that the eclogites were formed in the depth of at least 70 km, and the coesite-bearing eclogites in the depth of at least 120 km. In addition, the eclogites containing both the diamond and coesite in the depth of at least 145 km. It is unimaginable that the ultrahigh-pressure metamorphic rocks are uplifted to the earth surface from such depths. Many references show that the water is indispensable to the ultrahigh-pressure metamorphism. Based on the studies of the mineral dehydration, the geothermal curves and the phase change diagram of water, this paper indicates that such supercharges as the phase transformation booster in water greatly increase the lithostatic gradient in the process of the ultrahigh-pressure metamorphism. The depth for the formation of the ultrahigh-pressure metamorphic rocks calculated with hydrostatic pressure is only the greatest depth. However, the actual depth for the formation of the ultrahigh-pressure metamorphic rocks was much smaller than the theoretical depth as calculated with hydrostatic pressure.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2001年第1期13-17,共5页
Earth Science-Journal of China University of Geosciences
基金
教育部博士点基金项目! (No .980 14 0 0 3)
国家自然科学基金项目! (No .498730 0 9)
