矿物包裹体拉曼弹性温压计的验证及其地质应用

拉曼弹性温压计是一种独立于化学平衡之外的基于力学平衡的新型温压计。利用激光拉曼频移标定矿物包裹体在常压下储存的残余应力，结合矿物弹性特征，可恢复包裹体捕获时的温度和压力条件。目前被广泛应用于示踪俯冲带变质演化，特别是受后期退变质或热事件强烈改造的高压-超高压变质岩。本项目拟以桐柏-红安-大别-苏鲁造山带高压-超高压榴辉岩中广泛存在的石榴石-石英为研究对象，对不同变质压力条件下、不同变质阶段石榴石中石英包裹体，应用拉曼弹性矿物温压计，结合岩相学、矿物学及同位素地球化学等方法进行系统研究。利用传统的热力学温压计进一步验证拉曼弹性温压计地质应用的合理性和普适性，定量确定不同因素的影响程度。结果将用来示踪俯冲进变质信息，反演大陆俯冲带变质演化历史，进而探讨深俯冲构造演化过程。这是一个新的尝试，结果有望为拉曼弹性温压计的地质应用提供新的岩石学和地球化学制约。

The Raman elastic geothermobarometry is a new method, independent of the chemical equilibrium between coexisting minerals. The residual pressure measured by pressure-dependent Raman spectra of mineral inclusions is combined with elastic modeling to determine the entrapment P and T conditions for a single inclusion in a mineral host mineral. The elastic geobarometry for host-inclusion systems can provide new constraints on P-T conditions of polyphase metamorphism, especially later thermal overpringting due to the continuous re-equilibration of rock-forming and accessory minerals. This project focuses on the Raman elastic geothermobarometry, in combination with the systematic study of petrography, mineralogy and geochemistry, for host garnet and inclusion quartz in HP to UHP eclogites formed at different depths (the quartz, coesite and diamond stability fields) in the Tongbai–Hong'an–Dabie–Sulu orogenic belts. By comparing with the conventional geothermobarometries, the results will be used to verify the geological applicability of the Raman elastic geothermobarometry and the universality of different correction methods. As a consequence, we expect to provide new tight constraints on P-T-t conditions during the prograde metamorphism in continental subduction zones, reveal exact metamorphic history, and elucidate the formation and evolution of the collisional orogen.