Petrochemistry and geochemistry of HP metabasites from Haiyangsuo in Sulu UHP belt of eastern China |
| |
| Authors: | GUO Jinghui ZHAI Mingguo YE Kai LIU Wenjun CONG Bolin |
| |
| Institution: | Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China |
| |
| Abstract: | Abundant metabasites occur in highly deformed granitic and migmatitic gneisses as blocks and lenses of tens of meter size
around the Haiyangsuo area, northeast part of Sulu UHP belt, eastern China. They comprise garnet-pyroxene granulites, eclogitized
granulites and amphibolites. Their protolith compositions were mainly olivine tholeiite and quartz tholeiite, and show variation
from Mg-rich to Fe-rich component as tholeiitic cumulates. Pearce’s element ratio slopes suggested that protolith of these
rocks were comagmatic, and generated from a primary magma by fractional crystallization of plagioclase, olivine and clinopyroxene.
The crystallization differentiation has also been evidenced by trace elements, such as parallel REE patterns, Ni vs Ce variations,
Sr increasing depletions, although the large ion lithophile elements (LILE) were modified to different extent during metamorphism.
Trace element composition and Nd isotopes indicate a depleted mantle origin for these rocks. But they are not likely to be
fragments of ophiolites or tholeiites connected with subduction, they formed probably at intra-continent environment. Sm-Nd
whole rock isochron age of 2252±180Ma indicates approximately the formation age of igneous protolith of these rocks, almost
2000Ma earlier than the formation of the Dabie-Sulu UHP collision zone at about 240–220 Ma. |
| |
| Keywords: | ecoligitized granulite trace element Pearce’ s element ratio Sulu UHP belt |
| 本文献已被 万方数据 SpringerLink 等数据库收录！ |
|
