下地壳及壳幔过渡带化学不均一性──河北汉诺坝地区深源捕虏体元素地球化学证据  

HIGHLY CHEMICAL HETEROGENEITY IN THE LOWER CRUST AND CRUST-MANTLE TRANSITIONAL ZONE:GEOCHEMICAL EVIDENCES FROM XENOLITHS IN HANNUOBA BASALT, HEBEI PROVINCE

作　　者：张国辉[1] 周新华[1] 孙敏[2] 陈绍海[1] 冯家麟 

机构地区：[1]中国科学院地质研究所,北京100029 [2]香港大学地球科学系 [3]河北地质学院

出　　处：《地球化学》1998年第2期153-159,共7页Geochimica

基　　金：国家自然科学基金!49272097

摘　　要：河北汉诺坝玄武岩中长英质麻粒岩、镁铁质麻粒岩和辉石岩捕虏体的主量元素和微量元素特征，反映了下地壳及壳幔过渡带组成具有高度化学不均一性。不相容元素原始地幔标准化曲线特征的差异表明捕虏体成因复杂。MgO与不相容元素无或仅有很弱的相关性，与相容元素的相关性则相对较明显。这些特征反映了下地壳及壳幔过渡带存在较强和多元的混合作用。捕虏体的加权平均值比基于麻粒岩地体资料估算的下地壳平均组成偏基性，揭示了二者可能的成因差异。The major and trace element data of granulite and pyroxenite xenoliths, which are entrained in Hannuoba basalt Hebei Province, North China, suggest the highly chemical heterogeneity in the lower crust and crust-mantle transitional zone. There is no or only POor linear correlation between MgO and incompatible elements. Whereas a bit remarked correlations are observed between MgO and most compatible elements.The geochemical characteristics suggest that the strong and multiple mixing processes may have Occurred universally both in the lower crust and crust-mantle transitional zone. The weighed average composition of xenoliths shows a more mafic composition of the lower crust than that estimated from granulite data, which may imply the difference in the genesis.

关 键 词：地壳 下地壳 壳幔过渡带 元素地球化学 麻粒岩 

分 类 号：P595[天文地球—地球化学] P588.346[天文地球—地质学]