Island arc-trench system: mainly distributed in the western Pacific rim. According to the tectonic position of island arc or its correlation with the crust, island arc can be divided into continental margin arc and ocean inner arc. Continental marginal arc is an island arc separated from the mainland by shallow sea on the shelf, such as Taiwan Province Province, Sumatra Island and Java Island. The inner arc of the ocean is separated from the mainland by marginal sea or back arc basin and ocean crust.

The formation of ocean island basalt is generally considered to be related to mantle plume activity, and its composition range is wider than that of mid-ocean ridge basalt. It is generally believed that there are various heterogeneous mantle reservoirs in the lower mantle, such as high μ mantle (HIMU), enriched type I mantle (EM-I) and enriched type II mantle (EM-II).