基于磷灰石MgO含量的岩浆岩熔体成分计及其应用

磷灰石因其在各类岩石中广泛发育和能够容纳多种具有地质意义的元素而成为地质学研究中一个强有力的工具。本项目以岩浆岩磷灰石为研究对象，重点关注磷灰石MgO含量这一较少被以往研究所关注的成分。拟通过收集大量相平衡实验中磷灰石和平衡熔体成分数据、火山岩中磷灰石和共存玻璃成分数据、火山岩和侵入岩中磷灰石和全岩成分数据，揭示磷灰石MgO含量与平衡熔体MgO含量之间潜在的定量关系。在此基础上，拟通过分析云南腾冲全新世火山岩中磷灰石和共存玻璃成分进一步证实所发现的定量关系，从而建立基于磷灰石MgO含量恢复平衡熔体MgO含量的岩浆岩熔体成分计。最后对川西松潘-甘孜褶皱带和义敦岩浆弧晚三叠世侵入岩进行研究，将磷灰石MgO含量应用于探讨侵入岩是否大多数具有堆晶岩属性，为揭示火山岩与侵入岩的联系提供新的视角。

Apatite is a powerful research tool in geological studies because it is ubiquitous in various rocks and its ability to incorporate many useful elements. This project aims to study magmatic apatite and mainly focus on its MgO content which is less focused by previous studies. By compiling large compositional data of apatites and equilibrium melts in phase equilibrium experiments, apatites and coexisting glasses in volcanic rocks, volcanic apatites and bulk rocks, and plutonic apatites and bulk rocks, this project intends to decipher the potential quantitative relationship between apatite MgO and equilibrium melt MgO. The Holocene volcanic rocks in Tengchong area, Yunnan province are targeted for analyses for apatites and coexisting glasses, which is used to verify the proposed relationship. By doing these things, this project aims to calibrate a magmatic melt chemometry which can be used to quantitatively calculate melt MgO based on equilibrium apatite MgO. Finally, by using apatite MgO and the calibration, this project intends to decipher whether most plutonic rocks are cumulates in nature or not through a case study of the Late Triassic plutonic rocks in the Songpan-Ganzi Fold Belt and Yidun magmatic arc in the western Sichuan province. This will provide a new perspective on the relationship between volcanic and plutonic rocks.