盘石山幔源透辉石微量元素地球化学

用质子探针和电子探针分别测定盘石山幔源橄揽岩包体中透辉石、橄榄石的微量元素和主量元素丰度;用X-射线荧光光谱法测定包体全岩的主量和微量元素丰度。定量讨论微量元素的分布和分配。其中绝大部分Sr、Zr、Ti、Na赋存在透辉石中,绝大部分Mn、Zn、Ni赋存在橄揽石中,在T=1194-1435K范围,分配系数变化如下:InD_Ol/Cpx^Zn=1.44-2.19;InD_Ol/Cpx^Mn=0.21-0.40,InD_Ol/Cpx^Ti=4.76-5.61,InD_Ol/Cpx^Ni(平均值)=2.20.透辉石中Ti/Zr=42-103,低于原始地幔值,由地幔隐性交代作用造成。

TRACE ELEMENT GEOCHEMISTRY OF MANTLEORIGINATED DIOPSIDE FROM PANSHISHAN,JIANGSU PROVINCE

inor and trace element abundances of diopsides (Na, Mn, Ti, Al, Sr, Zr, Cr,Ni, Zn, Cu, Nb, Ba, etc.) and olivines (Ca, Mn, Ti, Zn, Ni, etc.) from spinel lherzolites from Panshishan Neogene alkalic basaltic volcanic rock, Luhe, Jiangsu Province, China analysed by proton microprobe (PMP) are reported here. Combining PMP data and mineral chemistry (by EMP) and major, minor and trace element data (by XRF) of whole rock of spinel lherzolites, the quantitative distribution of trace elements between mineral phases in mantle peridotites are discussed. Olivine and diopside are the main host mineral phase for trace element Ni, Mn and Zn and Ca.Sr.Ti and Na, respectively. The partitioning coefficients of Ti, Mn, Ni, Zn between olivine and diopside in different equilibrium temperatures (1200-1450K) are calculated. They are as function of temperature in form of van't Hoff's law- The behaviors of trace elements during cryptic metasomatism of continental lithospheric mantle under the area are deduced.