摘要
山东蒙阴金伯利岩中的橄榄石样品的OH红外光谱研究结果表明,在橄榄石的红外光谱图中,3 800～3 000cm-1范围内共有60多个νOH吸收峰。其中3 800～3 710cm-1范围内的νOH吸收峰主要是由空气中的水蒸气所引起的,并非橄榄石的本质或非本质νOH;3 710～3 620cm-1范围内的νOH吸收峰主要归属于蛇纹石、滑石、含镁闪石三种含水蚀变矿物相,是橄榄石的非本质νOH。含水矿物相中的H主要是在金伯利岩浆后期侵位期间进入橄榄石的;3 620～3 425cm-1范围内的νOH吸收峰源于H占据橄榄石结构中的Si空位后形成的硅镁石型缺陷,及(或)H占据橄榄石结构中的(Mg,Fe)等阳离子空位后形成的缺陷,因而是橄榄石的本质νOH。H主要是在地幔环境中,当橄榄石存在于高温的、富流体的金伯利岩浆中时进入橄榄石的;3 425～3 000cm-1范围内的νOH吸收峰主要是由流体水分子所引起的,是橄榄石的非本质νOH。流体水可以在地幔环境中,也可以在金伯利岩浆后期侵位期间进入橄榄石。
The results of FTIR spectra study of OH in olivines from Mengyin kimberlite show that there are more than 60OH absorption peaks in the range of 3 800～3 000cm^-1.We identified four major spectral features in the OH absorption bands of kimberlitic olivines.One is withνOHin the range of 3 800～3 700cm^-1,which is caused by the vapour of the room circumstance,and can not be regarded as intrinsic or non-intrinsicνOHof the olivines.Another one is withνOHin the range of 3 710～3 620 cm^-1,which belongs to three＂water＂-bearing minerals including serpentine,talc and Mg-bearing amphiboles,which is the nonintrinsicνOHof the olivines.There is the possibility that H in hydrous minerals mainly entered into olivines during post-emplacement processes of the kimberlite magma.The third one is withνOHin the range of 3 620～3 425cm^-1,which originated from H occupying the Si-defect in the olivine structure,forming humite-like defects,and/or the defects that H occupies（Mg,Fe）-depletion,which is certainly attributed to the intrinsicνOHof the olivines.In this case,H possibly entered into olivines following its immersion in the high temperature and rich fluid kimberlite magma in the mantle circumstance.The last one is withνOHin the range of 3 425～3 000cm^-1.In this area,νOHis assigned to fluid inclusions of the olivines,and is the non-intrinsicνOHof olivines.Fluid inclusions can enter into the olivines either during post-emplacement processes of the kimberlite magma or during the periods that olivines were formed in the mantle.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2013年第9期2374-2378,共5页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(41073021)
中央高校基本科研业务费专项资金项目(11lgpy02)资助
