Thermodynamic evolution of lithosphere of the North China craton:Records from lower crust and upper mantle xenoliths from Hannuoba  

作　　者：LIU Yongsheng GAO Shan LIU Xiaoming CHEN Xiaoming ZHANG Wenlan WANG Xuance 

机构地区：[1]Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China [2]The State Key Lab for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 2 10093, China [3]Key Laboratory of Continental Dynamics, Department of Geology,Northwest University, Xi'an 710069, China

出　　处：《Chinese Science Bulletin》2003年第21期2371-2377,共7页

基　　金：co-supported by the National Natural Science Foundation of China(Grants Nos.40133020 and 40003004);the Ministry of Science and Technology of China(Grant No.G1999043202);the State Key Lab for Mineral Deposits Research,Nanjing University;the Key Laboratory of Continental Dynamics,Northwest University.

摘　　要：Major element compositions of garnet, clino-pyroxene, orthopyroxene and spinel in the garnet-bearing lower crust and upper mantle xenoliths from Hannuoba, North China craton are analyzed by the electron microprobe (EMP). The pressure-temperature estimates reveal the in-creasing temperature and pressure from core to rim for granulites. In contrast, mantle xenoliths with core tempera-ture > 930℃ recorded a history of decrease in temperature and pressure. However, those with core temperature < 930℃ show a negligible change. The final pressures recorded by these xenoliths cluster at 0.9—1.5 GPa. The presence of high- Na2O cpx in granulite xenoliths suggests that they are prod-ucts of the transition from granulite to eclogite metamor-phism corresponding to the increasing temperature and pressure. Together with previous studies, it is suggested that the P-T changes preserved in the xenoliths are related to lithospheric thickening and subsequent thinning prior to their eruption in the Cenozoic.Major element compositions of garnet, clino-pyroxene, orthopyroxene and spinel in the garnet-bearing lower crust and upper mantle xenoliths from Hannuoba, North China craton are analyzed by the electron microprobe (EMP). The pressure-temperature estimates reveal the in-creasing temperature and pressure from core to rim for granulites. In contrast, mantle xenoliths with core tempera-ture > 930℃ recorded a history of decrease in temperature and pressure. However, those with core temperature < 930℃ show a negligible change. The final pressures recorded by these xenoliths cluster at 0.9—1.5 GPa. The presence of high- Na2O cpx in granulite xenoliths suggests that they are prod-ucts of the transition from granulite to eclogite metamor-phism corresponding to the increasing temperature and pressure. Together with previous studies, it is suggested that the P-T changes preserved in the xenoliths are related to lithospheric thickening and subsequent thinning prior to their eruption in the Cenozoic.

关 键 词：热力学 中国 北方地区 岩石圈 捕虏岩 岩石层位学 

分 类 号：P542[天文地球—构造地质学]