摘要
中国东部新生代碱性玄武岩及其幔源三辉橄榄岩捕虏体中的流体组分存在差异,幔源二辉橄榄岩形成于以H_2、CO等还原性气体为主的流体环境中,其流体组分以含H_2高、挥发性气体总量低为特征;碱性玄武岩中流体组分以CO_2、SO_2和挥发性气体总量高为特征,在其形成演化过程中有SO_2等氧化性气体的流体加入。碱性玄武岩及二辉橄榄岩捕虏体中的流体组成表明中国东部上地幔源区存在不均一性,碱性玄武岩浆在形成演化上存在地区差异性。中国东部大陆的上地幔中可能存在P_(H_2)较高的区域。
The components of the fluids released from alkali basalts and mantle-derived Iherzolite xeno-liths in eastern China have been determined by the vaccum pyrolysis-mass spectrometric (MS) method in the present study. The results show that mantle-derived Iherzolites formed in fluids composed mainly of reducing gases such as H2 and CO, and their fluid composition is characterized by a higher H2 content and a lower total content of volatiles. The fluids in alkali basalts are composed mainly of oxidizing gases such as CO2 and SO2 and characterized by higher contents of SO2 and volatiles, implying that the extraneous oxidized fluids which are composed mainly of SO2 mixed with primary alkali basaltic magmas during their formation and evolution. The fluid compositions of alkali basalts and Iherzolite xenoliths show high nonhomogeneity in the upper mantle source region and difference in alkali basaltic magma evolution in different districts. It can be deduced that the regions with higher PH2 could exist in the upper mantle beneath eastern China.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1999年第2期162-166,共5页
Acta Geologica Sinica
基金
国家自然科学基金(编号49233060
49133090)
