大别山及苏鲁地区微粒金刚石分类及其大地构造意义  

Classification of microdiamonds from eclogites of the Dabie Mountains and Sulu area, east-central China, and their tectonic implications

作　　者：徐树桐[1] 刘贻灿[1] 陈冠宝[1] 季寿元[2] 倪培[2] 萧万生[3] 

机构地区：[1]安徽省地质研究所 [2]南京大学地球科学系,江苏南京210008 [3]中国科学院广州地球化学研究所,广东广州510640

出　　处：《地质通报》2005年第12期1081-1088,共8页Geological Bulletin of China

基　　金：国家"973"专项<大陆板块会聚边界的地幔动力学与现代地壳作用>;国家自然科学基金项目(40399140;40172079)资助。

摘　　要：1992年发现大别山首例微粒金刚石之后,又于2003年和2004年在大别山和苏鲁地区的榴辉岩薄片中和榴辉岩的人工重砂中发现了微粒金刚石。本文报道其中尚未发表的7颗,并对2颗较大的薄片中的微粒金刚石和2颗自由晶体金刚石进行拉曼光谱和红外光谱测试。研究结果表明,本区所有微粒金刚石都为IaA和IaB型金刚石的混合体。缺少Ib型金刚石,表明没有人造金刚石的混入。薄片中的金刚石大部分为石榴子石的包裹体,少数产出于颗粒之间,直径为30～180μm。自由颗粒微粒金刚石直径为400～700μm。在大别山北部,不但又一次找到了微粒金刚石,还在石榴子石中发现有单斜辉石、磷灰石和金红石的出溶。这表明北大别不但是超高压地质体,而且可能是本区俯冲最深的地质体。After the first occurrence of microdiamond from the Dabie Mountains was reported in 1992, microdiamonds were found in thin sections of eclogite and heavy mineral concentrates of eclogite in the Dabie Mountains and Sulu area in 2003 and 2004. This paper reports seven of the microdiamonds that have not been pubhshed. Of these, two larger in situ microdiamonds in thin sections and two free crystal diamonds were identified by the Raman and infrared （IR） spectroscopy. All the microdiamonds in the region belong to a mixed type of type IaA and Type IaB diamonds while type Ib diamonds are absent, indicating that no synthetic diamonds are involved. Most diamonds in thin sections are inclusions in garnets, while a few occur in the interstices of the grains. They are 30-180μm across. The two flee microdiamonds are 400-700 μm in size. In the northern Dabie Mountains, not only microdiamonds have been found once again, but also clinopyroxene, apatite and rutile exsolution has been found in garnets. This suggests that the northern Dabie Mountains are not only an ultrahigh-pressure （UHP） terrane but also possible the deepest subducted terrane among the UHP terranes in the study region.

关 键 词：微粒金刚石 拉曼光谱 红外光谱 大别山 苏鲁地区 

分 类 号：P619.241[天文地球—矿床学]