西秦岭南部印支期郞木寺富斑晶安山岩的成因机制和岩浆通道系统

Andesites are major constituent of continent crust. They are commonly crystal-rich and display some mineral disequilibrium texture, which reflect they have experienced open-system magmatic processes and complex evolution histories. Combing detailed petrographic observations and quantitative textural measurements with geochemical in-site analyses allows us to get a better reconstruction of the complex evolution and dynamics of the magma system, and gain valuable insights into the origin and evolution of igneous rocks. This project will carry out an integrated study of field investigation, petrography, quantitative textural measurements, pressure and temperature calculation, thermodynamic modeling, whole-rock geochemical and Sr-Nd-Pb isotopic compositions for the Langmusi volcanic rocks, in the southern part of the West Qinling orogenic belt. Our aims are as follows: (1) elucidating the genesis of different crystal groups in volcanic rocks and their relationships with their host rocks; (2) reconstructing the whole magma evolution system and depicting the magma chamber processes; (3) constraining the tectonic evolution and geodynamic processes of the West Qinling orogen during the Indosinian; (4) getting a deep understand of the basic theory of igneous rocks, such as the nature of magma reservoir (magma chamber).

安山岩是地壳岩石的重要组成部分，通常表现出富含斑晶和一些不平衡的结构，反映其经历了开放的岩浆过程和复杂的演化历史。将详细的岩相学及定量结构分析和地球化学微区分析相结合，可以很好的重建整个岩浆系统复杂的演化和动力学过程，这将进一步提升对安山岩起源和演化的认识。本研究重点对西秦岭造山带南部郞木寺安山岩进了行详细的野外调查、岩相学、定量结构分析、矿物成分、地质温压计计算、岩浆热力学模拟，全岩主、微量元素及全岩Sr-Nd-Pb同位素的综合研究，阐明火山岩中不同晶体群的成因及与寄主之间的关系，重建火山岩演化的岩浆房通道系统和精细刻画岩浆房过程，并约束西秦岭印支晚期的构造环境和深部动力学过程，进一步深化对岩浆储库（岩浆房）性质等火成岩有关基础理论的认识。