Evolution of magma storage conditions along the track of Yellowstone Hotspot: investigation of the volcanic rocks from Snake River Plain

计划在斯内克河平原火山区（美国西部）进行的ICDP钻探旨在追踪斯内克河平原-黄石（SRPY）热点及其与岩石圈的相互作用。这个省是大陆岩石圈内与热点火山活动有关的热异常的最好例子之一。在过去的15 Ma，SRPY热点迁移约。向东600公里，形成双峰（流纹玄武岩）岩浆活动。了解SRPY热点与岩石圈的相互作用，需要流纹质和玄武质岩浆的化学演化，来源，分异和存储条件的时间和空间的信息。该项目旨在了解过去12 Ma SRPY省岩浆储存条件的演变。这些信息将通过以下方式获得：（1）天然矿物和玻璃的化学分析，结合（2）高压实验研究以确定相平衡，以及（3）热力学建模。将特别注意追踪流纹质岩浆房的深度和温度的演变，使用Bruneau-Jarbidge和海瑟火山中心（分别为12.5-8.0 Ma和6.5-4.3 Ma）作为参考材料。与此同时，将探索不同年龄的玄武熔岩的储存条件。研究结果还有助于了解玄武岩和流纹质岩浆房之间的相互作用，以限制在地壳部分熔融过程中的条件，并讨论流纹质熔体（岩浆）从源到岩浆房的垂直迁移距离。这项工作将受益于与美国岩石学家和地球化学家的合作（例如，E. Christiansen，B. Nash，J. Shervais）。

The planed ICDP drilling in the Snake River Plain volcanic province (western United States) is aimed to trace the Snake River Plain – Yellowstone (SRPY) hotspot and its interaction with the lithosphere. This province represents one of the best examples of a thermal anomaly related to hotspot volcanism within the continental lithosphere. Over the last 15 Ma, the SRPY-hotspot migrated ca. 600 km eastwards resulting in a bimodal (rhyolitic-basaltic) magmatism. Understanding the interaction of the SRPY-hotspot with the lithosphere requires information on the evolution of chemistry, sources, differentiation and storage conditions of both the rhyolitic and basaltic magmas with time and space. The proposed project aims at understanding the evolution of the magma storage conditions in the SRPY-province in the last 12 Ma. This information will be gained (1) from the chemical analysis of natural minerals and glasses combined with (2) high pressure experimental studies to determine phase equilibria and (3) thermodynamic modeling. Particular attention will be given to trace the evolution of the depth and temperature of the rhyolitic magma chambers using the Bruneau-Jarbidge and Heise volcanic centers (12.5-8.0 Ma and 6.5-4.3 Ma, respectively) as reference materials. Concomitantly, the storage conditions of basaltic lavas of different ages will be explored. The results will also be useful to understand the interactions between basaltic and rhyolitic magma chambers at depth, to constrain the conditions prevailing during partial melting processes in the crust, and to discuss the vertical migration distance of rhyolitic melts (magmas) from the source to the magma chamber. This work will benefit from the cooperation with petrologists and geochemists from USA (e.g., E. Christiansen, B. Nash, J. Shervais).