Abstract
Sapphires from alluvial deposits associated with Cenozoic basalts in Southern Vietnam were collected for investigation of mineral inclusions. In this report, primary iron oxide inclusions were focused on, with detailed mineral chemistry using a Raman spectroscope and electron probe micro-analyzer. Consequently, a variety of iron oxide inclusions were recognized as wüstite, hercynite, and ilmenite. Ilmenite falling within an ilmenite–hematite series ranged in composition between Il24-30He36-38Mt35-40 and Il49-54He34-40Mt7-10, classified as titanomagnetite and titanohematite, respectively. Wüstite with non-stoichiometry, (Fe2+0.3-0.9)(Ti3+<0.179Al3+≤0.6Cr3+<0.1Fe3+≤0.46)☐≤0.23O, was associated with hercynite inclusions, clearly indicating cogenetic sapphire formation. Wüstite and sapphire appear to have been formed from the breakdown reaction of hercynite (hercynite = sapphire+wüstite) within a reduction magma chamber. Titanohematite and titanomagnetite series might have crystallized during iron–titanium reequilibration via subsolidus exsolution under a slightly oxidized cooling process.
Subject
Geology,Geotechnical Engineering and Engineering Geology
Cited by
4 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献