山东蒙阴金刚石多晶的显微红外光谱研究及其成因意义  

Study on the Micro-Infrared Spectra and Origin of Polycrystalline Diamonds from Mengyin Kimberlite Pipes

作　　者：杨志军[1,2] 梁榕[1] 曾祥清[1] 葛铁燕[1] 艾群[1] 郑云龙[1] 彭明生[1] 

机构地区：[1]中山大学地球科学系,广东广州510275 [2]广东省地质过程与矿产资源探查重点实验室,广东广州510275

出　　处：《光谱学与光谱分析》2012年第6期1512-1518,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41073021);广东省自然科学基金项目(9151027501000088);中央高校基本科研业务费专项(11lgpy02);中山大学重点培育计划项目(32110-1132291)资助

摘　　要：山东蒙阴金刚石多晶可划分为多角刻面状和浑圆状金刚石多晶两大类,它们的显微红外光谱研究结果表明,金刚石多晶中的氮含量较低,介于16.69～72.81μg.g-1之间,且同一金刚石多晶的不同金刚石晶粒(或部位)中的氮含量不相同;刻面状金刚石多晶均为ⅠaAB型,且A心的浓度大于B心的浓度。浑圆状金刚石多晶也多为ⅠaAB型,但具有更高浓度的B心,且存在少数同时包含单替代氮、A心和B心的浑圆状金刚石多晶;金刚石多晶不是在金刚石颗粒的成核阶段所形成的,而是在金刚石长大期间或金刚石颗粒形成后的某个特殊条件下聚集而成;山东蒙阴金刚石多晶可能形成于氮浓度较低的较深部地幔。同时,多角刻面状金刚石多晶的形成时间稍晚于金刚石单晶体,浑圆状金刚石多晶的形成时间明显早于金刚石单晶体。The natural polycrystalline diamonds from the Mengyin kimberlite pipes can be classified as the euhedral faceted polycrystalline diamonds and anhedral rounded polycrystalline diamonds.The results of micro-FTIR spectra characterization of the polycrystalline diamonds show that the concentration of nitrogen is low,varying from 16.69 to 72.81 microgram per gram and is different among different diamond grains or position in polycrystalline diamonds.The euhedral faceted polycrystalline diamonds are ⅠaAB type and have higher concentration of A-center defects than B-center defects.Most of the anhedral rounded polycrystalline diamonds are ⅠaAB type and have higher content of B-center defects.A minority of the anhedral rounded polycrystalline diamonds have C-center,A-center and B-center defects simultaneously.The polycrystalline diamonds probably originated from the relatively deeper mantle and were not formed in diamond nucleation stage,but in the diamond growth period or some special conditions after the diamond grains were formed already.Furthermore,the euhedral faceted polycrystalline diamonds were formed slightly later and the anhedral rounded polycrystalline diamonds were formed obviously earlier than the diamond single crystals from the Mengyin kimberlite pipes.

关 键 词：金刚石多晶 显微红外光谱 氮 成因 

分 类 号：TG115.2[金属学及工艺—物理冶金]