摘要
Trace element compositions of garnet, omphacite and apatite in ultrahigh-pressure eclogites from the main hole of the Chinese Continental Scientific Drilling (CCSD) project were in situ analyzed by the LA-ICP-MS method. Although both garnet and omphacite have homogeneous major element composi-tions, their trace elements show zonations from core to rim in rare earth elements. In particular, middle rare earth elements in the garnet, heavy rare earth elements in the apatite and all rare earth elements in the omphacite increase from core to rim, respectively. Based on dependence of partition coefficients on temperature and pressure in these minerals, we suggest that the trace elemental zonations in these minerals may record a short-lived heating event during exhumation.
Trace element compositions of garnet, omphacite and apatite in ultrahigh-pressure eclogites from the main hole of the Chinese Continental Scientific OriUing （CCSO） project were in situ analyzed by the LA-ICP-MS method. Although both garnet and omphacite have homogeneous major element compositions, their trace elements show zonations from core to rim In rare earth elements. In particular, middle rare earth elements in the garnet, heavy rare earth elements in the apatite and all rare earth elements in the omphacite increase from core to rim, respectively. Based on dependence of partition coefficients on temperature and pressure in these minerals, we suggest that the trace elemental zonations in these minerals may record a short-lived heating event during exhumation.
基金
Supported by the Ministry of Science and Technology of China (Grant No. 2003CB716501)
the National Natural Science Foundation of China (Grant Nos. 40521001 and 40473013)
the Program for New Century Excellent Talents in Uni-versity (Grant No. NCET-05-0664)
the State Key Laboratory of GPMR, China University of Geosciences (Grant No. GPMR0511)
the State Key Laboratory of Continental Dynamics, Northwest University, China
