Mantle metasomatism by P- and F-rich melt/fluids: evidence from phosphate glass in spinel lherzolite xenolith in Keluo, Heilongjiang Province  

作　　者：ZHANG WenLan SHAO JiAn XU XiSheng WANG RuCheng CHEN LiHui 

机构地区：[1]State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, Nanjing University, Nanjing 210093, China [2]School of Earth and Space Science, Peking University, Beijing 100871, China

出　　处：《Chinese Science Bulletin》2007年第13期1827-1835,共9页

基　　金：the National Natural Science Foundation of China (Grant Nos.40672039, 40221301, 40125007 and 40372103)

摘　　要：Spinel lherzolite xenoliths were found in phonolitic alkaline basalt in the Keluo area, Heilongjiang Province. Detailed electron-microprobe study revealed abundant phosphates and associated metasomatic minerals between primary phases in xenolith. The phosphates are considered special residual phases (coagulation) of P- and F-rich mantle melt/fluid, most of which were identified as glass phases based on Raman spectroscopic analyses. Such melt/fluid also further metasomatized primary minerals, thus leading to formation of reaction rims successively composed of Cr-spinel symplectitic zone and olivine + diopside zone. Therefore, the P- and F-rich melt/fluid played an important role in the upper-mantle metasomatism in the Keluo area. It is suggested that this kind of metasomstism may occur in some other places of eastern China. The present results may also have significance in study-ing types of metasomatic melt/fluid and its evolution in the lithospheric mantle beneath eastern China.Spinel Iherzolite xenoliths were found in phonoliUc alkaline basalt in the Keluo area, Heilongjiang Province. Detailed electron-microprobe study revealed abundant phosphates and associated metasomatic minerals between primary phases in xenolith. The phosphates are considered special residual phases （coagulation） of P- and F-rich mantle melt/fluid, most of which were identified as glass phases based on Raman spectroscopic analyses. Such melt/fluid also further metasomatized primary minerals, thus leading to formation of reaction rims successively composed of Cr-spinel symplecUUc zone and olivine ＋ diopside zone. Therefore, the P- and F-rich melt/fluid played an important role in the upper-mantle metasomatism in the Keluo area. It is suggested that this kind of metasomstism may occur in some other places of eastern China. The present results may also have significance in studying types of metasomatic melt/fluid and its evolution in the lithospheric mantle beneath eastern China.

关 键 词：地幔 捕虏体 磷酸盐 玻璃 玄武岩 

分 类 号：P588[天文地球—岩石学]