橄榄石中轻-超轻元素（P-Li-H）的赋存状态和扩散对岩浆过程及其时限的制约

幔源岩浆体系演化的时空尺度是认识岩浆上涌、岩浆房动力学过程以及地表火山喷发机制的关键。橄榄石中轻-超轻元素（P-Li-H）的赋存状态和扩散可揭示岩浆房中复杂的岩浆过程及其时限。本项目将采用EBSD、TEM、LA-ICPMS、SIMS和FTIR等高精度原位分析技术，选取峨眉山大火成岩省攀西地区的阿布郎当、红格、攀枝花和白马岩体以及大理-丽江苦橄岩中的橄榄石开展轻-超轻元素的赋存状态和扩散研究。通过研究不同层位和不同类型岩石中橄榄石的P-Li-H的分布特征，揭示岩浆房中对应的岩浆过程；研究橄榄石中P-Li-H的赋存状态和替换机制，查明控制其分配的物理化学因素；模拟橄榄石P-Li-H扩散曲线记录的扩散时间，反演岩浆过程持续的时限，建立峨眉山地幔柱岩浆体系形成和演化的时间尺度模型。本研究为探究幔源岩浆体系时空演化提供了新思路，这是之前有关峨眉山地幔柱岩浆体系研究没有涉及的领域，有望取得新进展。

The time-scale of formation and evolution of a magmatic system is key to understanding the upwelling of magma, dynamic processes in the shallow magma chamber and magma eruption at surface. Occurrence and diffusion of P-Li-H in olivine can record complex magmatic processes and their lasting time. This project will use multiple in situ micro-analytical techniques such as EBSD, TEM, LA-ICPMS, SIMS and FTIR to study the occurrence and diffusion of P-Li-H in olivine from the mafic-ultramafic intrusions in the Panxi region and picrite in the Dali-Lijiang area in the Emeishan large igneous province. It is aimed to study the distribution patterns of P-Li-H in olivine from different types of rocks and related magmatic processes; to investigate the occurrences and substitute mechanisms of P-Li-H in olivine and find out the physical and chemical factors that influence the chemical behaviors of these elements; and last to calculate the diffusion time according to the P-Li-H diffusion profiles within olivine, which eventually providing us a chance to constrain the time-scale of the Emeishan mantle plume magmatic system. This project will provide new ideas for investigating the time-space evolution of mantle-derived magmatic system. This is an area that has not been covered for the Emeishan mantle plume magmatic system and is expected to make new progress.