豫西石宝沟花岗岩体及其中暗色微粒包体的成因研究

The Shibaogou granite pluton, which is located in the Western Henan Province, the southern margin of the North China Plate, consists of two stages including about 158Ma and about 145Ma of age with different rock types, and the midium-course-grained porphyritic monzogranite contains abundant mafic microgranular enclaves(MMEs). This program is planned to investigate the petrogenesis of the Shibaogou granite pluton and its tectonic setting from the following procedures including: 1) to distinguish the relationships between the MMEs and their host granite on the basis of the detailed field and microscopic observations, the conventional geochemistry analysis, and their zircon U-Pb ages, 2) to trace the mantle material in the Shibaogou granite pluton via in-situ zircon Hf-O isotopic composition research after excluding the supersolidus high temperature hydrothermal alteration, 3) to constrain the temperature and the pressure of the primary magma of the pluton though mineral thermobarameters including Ti-zircon thermometer and hornblende barometer and by comparison with experimental results.

石宝沟花岗岩岩体位于豫西华北板块南缘，由约158Ma和约145Ma两个阶段多种岩性的花岗岩组成，其中的中粗粒似斑状二长花岗岩中含有大量暗色微粒包体（MMEs）。本项目拟1）在详细地野外地质和显微镜下观察、常规地球化学研究和锆石U-Pb测年的基础上，鉴别MMEs与寄主花岗岩的关系，2）采用锆石原位微区稀土元素分析方法检查锆石是否遭受了超固相线温度条件下的热液蚀变作用，在此基础上采用锆石微区原位Hf-O同位素分析识别石宝沟岩体的形成是否有地幔岩浆的贡献，3）采用锆石Ti温度计和角闪石矿物压力计限定和反演其原始岩浆源区的温压条件，同时对比实验岩石学资料为温压条件提供约束。在此基础上，为石宝沟岩体的成因及其构造环境提供约束。