豫西新生代玄武岩中橄榄石粒度分布研究

OLIVINE CRYSTAL SIZE DISTRIBUTION OF CENOZOIC BASALT OF WESTERN HENAN PROVINCE

运用晶体大小分布理论并结合岩石学和矿物学的资料,讨论了豫西伊川—汝阳新生代碱性橄榄玄武岩中的橄榄石晶体大小分布的成因,初步认为研究区碱性橄榄玄武岩中的橄榄石晶体大小分布形式很可能不是岩浆混合形成的,而是岩浆演化造成的。它对应着岩浆演化的三个阶段:岩浆房演化阶段、岩浆上升阶段和岩浆淬火阶段。分析了岩浆房演化阶段和岩浆上升阶段橄榄石晶体生长的动力学条件。

Based on petrographic analysis and olivine crystal size measurement, crystal size distributions of olivine of Cenozoic basalt in Yichuan-Ruyang region (western Henan Province, China) is analyzed. Three distinct episodes are detectable from olivine crystal size distributions, an early crystallization of olivine in magma chamber, an ascent phase which may be with a varied growth rate of olivine and a quenching phase. In addition to geochemical and mineralogic evidence, the similarity of the olivine crystal size distribution of individual samples makes it possible to exclude the possibility that the olivine crystal size distribution of basalt in this region is due to mixing of different populations.