桂北和桂东北不同时代煌斑岩研究及其对华南中生代构造体制的约束

华南在中生代经历了由特提斯构造域向太平洋构造域的构造体制转换，然而对其转换时限、深部壳-幔作用及动力学背景的认识存在分岐。广西地处滨太平洋与特提斯两大构造域的复合部位，区内分布的中生代煌斑岩是研究这些分歧的最佳对象。本项目拟选择桂北柳州三江（印支期？）和桂东北平乐沙子（燕山期？）两处典型煌斑岩为研究对象，以野外地质为基础，利用矿物学、岩石学、地球化学和同位素年代学等研究方法，精确限定这些煌斑岩的侵位时代、地球化学特征和地幔源区性质，探明其岩浆起源及形成时的构造背景，从而对华南中生代构造体制进行有效约束。本项目将为理解华南中生代岩石圈地幔特征和大陆动力学背景提供重要资料。

The tectonic regime in South China underwent a tremendous transition during the Mesozoic, although the timing of transition, deep crust-mantle interaction and dynamic background are still controversial. Guangxi is located in the transform bounder between the Pacific and Tethyan tectonic domain, with the Mesozoic lamprophyres in it are ideal objects to solve these problems. We plan to present detailed field geology, mineralogy, petrology, geochemistry and geochronology for the lamprophyres (Indosinian?) in Sanjiang, Liuzhou in northern Guangxi and lamprophyres (Yanshanian?) in Shazi, Pingle in northeastern Guangxi to constrain the emplacement age, geochemistry features and mantle characteristics of the lamprophyres. This project intends to uncover the source of magma, tectonic setting of the lamprophyres and further to constrain the tectonic regime in South China during the Mesozoic. Furthermore, this study will lead a better understanding of the features of lithosphere mantle and continental dynamic background in South China.