石榴子石的高温塑性：地幔转换带的流变特性

HIGH TEMPERATURE PLASTICITY OF GARNETS:RHEOLOGY OF THE MANTLE TRANSITION ZONE

介绍了近年来国际地球物理学界在石榴子石相矿物高温塑性实验研究领域取得的进展和它的意义。这些实验研究进展表明地幔转换带内的富石榴子石岩层的流变强度要大大高于相邻深度的其它矿物相，从而导致地幔转换带流变非均匀性。这种由于矿物组分差异产生的地幔流变性非均匀性对地幔转换带地球动力学特征有着十分重大的影响。首先，石榴子石相矿物在很大程度上决定了那里的强度结构，并控制了地幔转换带的流变性。第二，中、深源地震的成因在很大程度上与石榴子石相矿物流变特性有关，第三，地幔转换带流变的非均匀性将影响到俯冲板块的下插深度和消减过程，最后，对这一课题的未来研究方向和问题作了简单的介绍。

This paper empasized the plasticity of the garnets. All the works showed a higher creep strength of the garnet-rich layer and the creep inhomogeneity in the trnasition zone. This mineralogical-induced creep stratification has an important effect on the geodynamics of the mantle tranaition zone. First, the higher creep strcngth of garnets determines the flow strength of the mantle transition zone; Second,it has much to do with the origin of the medium-deep strong earthquake;Third, the creep inhomogeneuty of the mantle transition zone will affect the depth at which the descending slab could penetrate.This paper diseussed also the problems which we should work on in the future.