图7. 地幔交代岩熔融形成安山岩的概念模型图解（据参考文献[119]修改）
展示了地幔交代岩熔融形成安山岩关键的4个步骤：\mathrm{①}俯冲洋壳在弧前深度脱水；\mathrm{②}俯冲洋壳与俯冲沉积物在弧下深度部分熔融；\mathrm{③}富水的长英质熔体与地幔楔橄榄岩反应形成镁铁质—超镁铁质的交代岩；\mathrm{④}玄武质交代岩部分熔融形成安山质熔体，可能的熔融机制包括:地幔交代岩的底辟上升(4a),板片的拖曳作用(4b)以及板片的回卷作用(4c)^[119]

Fig.7. Schematic diagram of conceptual model of andesite formed by melting of mantle metasomatites（modified after reference [119]）
Schematic diagram showing the four key steps for origin of andesites by melting of mantle metasomatites： \mathrm{①} Dehydration of the subducting oceanic crust at forearc depths； \mathrm{②} Partial melting of the subducting sediment and altered oceanic basalt at subarc depths; \mathrm{③} Reaction of the hydrous felsic melts with the mantle wedge peridotite to generate the mafic-ultramafic metasomatites； \mathrm{④} Partial melting of basaltic metasomatites to produce the andesitic melts, the possible melting mechanisms include: Diapir of basaltic metasomatites (4a), slab dragging (4b) and slab rollback (4c)^[119]