High-Mg andesites and their geodynamic implications
高镁安山岩及其地球动力学意义

High-Mg andesites (HMAs) have recently been one of focuses on the international geological research. In this paper, we mainly introduce the classification, petrogenesis, metallogeny and geodynamic implications of the HMAs. The HMAs can be classified as adakitic, bajaitic, sanukitic and boninitic sub-types. The HMAs may contain mantle-derived component, and subducted oceanic slab (basaltic oceanic crust or sediments) or subducted sediment-dominated continental crust-derived melts (or fluid), or sometimes delaminated lower crust-derived melts. The HMAs may be directly generated by partial melting of mantle peridotite or the interaction between melts and mantle peridotites. The geological setting for the HMAs is very special. Except the Cenozoic HMAs in the central Tibet plateau, nearly all other Cenozoic HMAs occur along the boundaries between convergent plates, and their petrogenesis is mainly related to the subdution of young and hot oceanic crust or oceanic ridges. The HMAs provides key insights into the continental crustal growth and metal mineralization. Some problems regarding the present research on the HMAs are discussed at last.