辽宁金刚石中矿物包裹体标型特征及其意义

TYPOMORPHIC PECULIARITIES AND SIGNIFICANCE OF MINERAL INCLUSIONS IN DIAMOND IN LIAONING PROVINCE, CHINA

辽宁金刚石中矿物包裹体的化学成分和组合特征属于典型的橄榄岩壁，具有重要标型意义的矿物包裹体主要有镁橄榄石、铬镁铝榴石、铬铁矿等．由单晶金刚石与微晶金刚石相互交替生长而构成的结构环带以及由成分复杂的壳源物质构成的成分环带，分别具有重要的成因意义．以EPMA、LRM及宝石显微镜为研究手段，从金刚石中矿物包裹体标型特征这一角度，揭示了辽宁部分金刚石的不平密结晶作用过程具不连续性和多阶段性；金伯利岩岩浆在侵位过程中，其侵入速率曾发生过周期性变化，并发生再结晶而形成金刚石。进一步验证了辽宁大多数金刚石不属岩浆结晶产物而是地幔捕虏晶这一推论。

The chemical compositions and combination features of the mineral inclusions in the diamond from Liaoning Province, China, belong to the typical peridotite type. The important typomorphic mineral inclusions are mainly composed of forsterite chrom-pyrope and chromite. The structural zoning composed ot alternate growth of monocrystalline diamond and microcrystalline diamond and the compositional zoning composed of crustal-source materials with complex chemical compositions are important respectively in origin. In this paper, the discontinuous and multi-stase feature of the unequilibrium crystallization of the dtamond from Liaoning Province are presented in terms of the typomorphic peculiarities of the mineral inclusions in the diamond and by means of the EPMA, LRM and gem microscope. In the process of the emplacement of the kimberlite magma, the corresponding emplacement rate chansed periodically.It has been fUrther proved that the ma jority of the diamond from the Liaoning Province results from the mantle xenocryst, instead of the magmatic crystallization.