菲律宾吕宋岛新生代埃达克岩被广泛认为与南海板片的俯冲密切相关，因此对新生代埃达克岩的岩石地球化学的研究，对于揭示南海板片的俯冲过程具有重要意义。由于前人多注重于对俯冲板片的间接产物研究，如玄武岩、辉长岩和安山岩；而对直接源于板片熔融的埃达克岩成因机制认识不足，导致对南海的俯冲机制争议较大。本项目拟选择菲律宾碧瑶地区三个经典剖面的埃达克岩作为研究对象，对埃达克岩进行系统的岩石地球化学研究，重点利用全岩Sr-Nd-Pb同位素示踪技术确定埃达克岩的源区，并将其与南海和菲律宾海板片进行对比，探讨不同地质端元在埃达克岩形成过程中的贡献；结合元素地球化学和年代学数据，分析新生代埃达克岩地球化学特征演化规律，探讨南海板片的俯冲过程。本课题不仅可以丰富和拓展对南海俯冲和消亡过程的广度和深度，而且可以为探讨板片俯冲过程中的岩浆活动这一国际地学前沿问题提供新的思路。

Cenozoic adakites in Luzon (Philippines) have been widely considered to be related with the subduction of the South China Sea, it is necessary to study the geochemistry of those adakites to explore the subduction process of the South China Sea. However, previous studies were focused on indirect products of slab subduction, i.e. basaltic magmas and andesites, while insufficient work have carried out on the Cenozoic adakites which are direct products of slab melting. This leads to controversies on mechanism of the subduction process of the South China Sea beneath the Luzon arc island. This program will carry out geochemical investigation of Cenozoic adakitic magmas in 3 locations in Baguio District. By utilization of whole-rock Sr-Nd-Pb isotopic tracing technique, we will define the source of these adakitic magmas. With aims of identifying contribution of different end-members on production of Cenozoic adakitic magmas, we will compare geochemical characteristics of Cenozoic adakitic magmas with that of the South China Sea plate and the Philippine Sea plate. Combined with geochronology and element geochemistry, the evolution of geochemical characteristics of Cenozoic adakitic magmas will be established to discuss the subduction process of the South China Sea. This program will deepen and widen the understanding of the subduction and extinction process of the South China Sea beneath the Luzon Island; besides, it will provide new evidence for understanding of subduction zone magmatism.