中文摘要:金刚石及其紧密伴生的镁铝榴石、铬尖晶石、钛铁矿、单斜辉石及橄榄石,形成于高温,尤其是高压的上地幔条件下,被快速上升的金伯利岩浆携带至地表,这些矿物形成的特殊的地质条件和环境,必然反映到它们的矿物学特征上来。文章通过对我国金伯利岩中金刚石伴生矿物的研究,探讨了金伯利岩含金刚石性的矿物学标志。
Abstract:In kimberlites, diamond is associated with pyrope, picotite, ilmenite, clinopyroxene and olivine, whose physical and chemical properties reflect to some extent their high temperature and especially high pressure formation conditions. The higher the Ⅳ, ao, D, Cr2O3, Cr/(Cr+Al), (Mg3Cr2Si3O12) and Cr component in pyrope,, the richer the diamond that kimberlites contain. Picotite from diamond-rich kimberlites contains higher Cr2O3, Cr/(Cr+Al), Cr/(Cr+Al+Fe3+), MgCr2O4 and Cr component than that from kimberlites with little or no diamond. The lower the infrared absorption frequencies of pyrope and spinel in kimberlites, the richer the diamond in kimberlites. With the increase in QS[Fe3+(B)] and decrease in QS[Fe3+(B)] and QS[Fe3+(A)] in picotite, kimberlites become increasingly richer in diamond; with the increasing MgO, MgTiO3 and Cr2O3 content in megacrystalline and coarse-crystallized ilmenite, diamond content of kimberlites tends to increase. Compared with clinopyroxene in kimberlites with little or no diamond, clinopyroxene in diamond-rich kimberlites contains lower Ca/(Ca+Mg), Ca/(Ca+Mg+Fe) and tschermak molecules but higher Mg/(Ca+Mg+Fe), Cr2O3 and AlⅢ/AlⅣ. Olivine in diamond-bearing kimberlites is rich in MgO, forsterite molecules, Cr2O3 and NiO.
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董振信, 丛安东, 韩柱国.1993.金伯利岩含金刚石性的矿物学判别标志[J].矿床地质,12(1):48~54.1993.Mineralogical Criteria For Determination Of Diamond Content In Kimberlites[J].Mineral Deposits12(1):48~54
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