中国东南沿海白垩纪花岗质火山-侵入杂岩岩浆起源与演化

针对花岗质岩浆起源与演化过程中存在的重要前沿科学问题，利用中国东南沿海11个白垩纪花岗质火山-侵入杂岩及相关岩石地质出露良好、时空关系密切的独特优势，在以往研究基础上，对各岩石单元进行地质详查，重点地区进行小比例尺填图；系统地精确研究它们的形成年龄，深入揭示它们的时序、跨度和脉动性；结合详细的岩相学研究、矿物温压计和热力学模拟，定量估算各阶段岩浆结晶的P-T-XH2O-fO2条件，探究控制火山岩和侵入岩成分异同的岩浆过程，揭示它们可能的内在成因联系，特别是结晶分异-熔体抽离过程；通过Sr-Nd-Hf-O多元同位素和Fe、Si非传统同位素分析，鉴别和约束岩浆混合过程及壳-幔组分比例，深入揭示花岗质火山-侵入杂岩形成过程中幔源玄武质岩浆底侵的影响。通过浅成火山-侵入杂岩与同时代深部侵位花岗岩对比研究，探究地壳成分分层与岩浆作用的关系，提升对花岗质岩石成因精细过程与活动大陆边缘地壳演化的认知。

This project will focus on the fundamental questions of the origin and evolution of granitic magma, by detailed studies of eleven well exposed Cretaceous volcanic-plutonic complexes and related rocks along the coast of southeast China, taking advantage of the close spatial-temporal relationship between volcanic and plutonic members for these complexes. This project intends to perform detailed geological survey of these volcanic-plutonic complexes and small-scale mapping in key areas based on published literature, and determine their formation ages by high-precision dating methods to reveal the sequence, duration and pulsing of magmatism. Integrating detailed petrography, thermobarometer and thermodynamic modeling to estimate P-T-XH2O-fO2 crystallization conditions, this project will also explore the magma processes that control compositional similarity/difference, and reveal the intrinsic genetic connection between volcanic and plutonic rocks, especially the fractional crystallization-melt extraction process. Identification and quantification of crust-mantle components will be done using the Sr-Nd-Hf-O isotopes and non-traditional isotopes (Fe and Si), to reveal the influence of mantle-derived basaltic magma underplating during the formation of the granitic volcanic-plutonic complexes. Comparative studies of the volcanic-plutonic complexes with their contemporary, deep-seated granitoids will probe into the relationship between magmatism and compositional stratification of continental crust, which will ultimately improve our understanding of the detailed processes of granitic magma crystallization and crustal evolution in active continental margins.