P-Wave Velocity in Rocks of Dabieshan, China at High Pressure and High Temperature: Constraints for Composition of Lower Crust and Crust-Mantle Recycling

查看全文 作　　者：Zhao Zhidan;Zhou Wenge;Xie Hongsen;Guo Jie;Xu Zuming(Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002)Zhang Zeming(Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037) 出　　处：《Journal of Earth Science》索引1999年第18卷第4期,共4页 摘　　要：P-wave velocities in the rocks of Dabieshan, central China were measured at pressures up to 5.0 GPa and temperatures up to 1 300℃. The ultrahigh pressure eclogites have the highest density and P-wave velocity (Vp) and lower anisotropy. Pressure derivatives of the eclogites range from 0. 22 to 0. 33 km. s-1 GPa-1. Average temperature derivative of the eclogites is - 3. 41×10-4 km. s-1. °C -1. The density and VP of the eclogites imply that there will be two united possibilities related to crust-mantle recycling after the eclogite formed in the deep lithosphere. One is that some eclogites in the deep lithosphere were detached and sunk into deeper mantle due to their denser density. Another is that some eclogites returned to the crust and exposed to the surface.Small amounts (<12%) of eclogites may be still exist in the deep crust beneath Dabieshan based on our calculation. 关 键 词：ECLOGITE P-WAVE velocity density HIGH pressure HIGH temperature lower CRUST