近年来的实验和理论研究表明，组成矿物的同位素特征可以作为判断岩石Li同位素体系的成因的依据。申请人最近对花岗岩的主要组成矿物的初步研究结果显示，成岩矿物之间存在巨大的Li同位素平衡分馏；?△7Li石英-石榴石达到了+37‰。这些初步的结果对于解释涉及这些矿物的地质过程的Li同位素体系具有重要意义。本申请拟在此基础上进一步开展工作，通过对大别苏鲁地区的各种典型岩石的矿物Li同位素的详细调查，来探讨：（1）花岗岩的岩浆演化的过程中是否存在明显的Li同位素分馏（2）不同地质体系中矿物间Li同位素的分馏机制；（3）榴辉岩的极低d7Li值成因的矿物学证据；（4）不同深度的地幔楔受到俯冲流体改造时矿物的Li同位素变化；（5）HIMU型OIB 的Li同位素形成特征的矿物分馏效应。有关成果将为Li同位素地球化学的一系列基础问题提供限定。同时，我们将尝试在项目执行期间建立起自己的Li同位素的分析系统。

Recently experimental studies on inter-mineral lithium (Li) isotopic fractionation suggest that, Li isotopic compositions between co-existing minerals could be used to evaluate Li isotope equilibria of the bulk system. Most recently the applicant has investigated the Li isotopic compositions of the rock-forming minerals of granites from the Bengbu area. The data show that there is an extreme Li isotope equilibrium fractionation between quartz, feldspar, garnet and mica. The? ?7Li between quartz and garnet is up to +37 ‰. These preliminary results are important for understanding the Li isotope system of geological processes involved in these minerals. Taking various minerals from typical rocks of the Dabie-Sulu area that represent geological settings ranging from continental crust to subduction zones and mantle wedges as the study objects, we try to explore: (1) whether there are significant Li isotope fractionation during the magma evolution of granite,（2） the mechanism of inter-mineral Li isotope fractionation in verious geological systematics, (3) mineralogical evidence for evaluating the origin(s) of extremely depleted 7Li in eclogites, (4) information of slab/mantle interaction recorded by mineral Li isotopic compositions of mantle wedge from different depths, and (5) the role that mineral phase may play during the formation of characteristics Li isotopic compositions of HIMU-type OIB. The results may provide important constraints for a few basic issues in Li isotope geochemistry. Meanwhile, we will try to set up our own Li isotope analytical system during the running of the project.