Abstract:

Comparison of petrologic and geochemical characteristics of plumerelated (Panxi area) and non plumerelated (South China, Central Asian Orogenic Belt) A-type granites have been carried out in this study. It is shown that the plume-related A-type granites are characterized by (1) the close temporal and spatial association with maficultramafic rocks; (2) high zircon saturation temperature (860-960℃); (3) high Nb/Th and Ga/Al ratios, and (4) positive ε_Nd（t） (but usually <5) and no significant difference between Nd model age and the formation age of the rocks. All these characteristics, largely relevant to the nature of the plume-generated magma source and/or parental magmas, and magmatic evolution, can be used to identify similar rock types in natural occurrence.

Key words: A-type granite, mantle plume, Emeishan large igneous province, juvenile crust