Abstract Silicic magmas play an important role in the formation of continental crust and are responsible for some of the most hazardous volcanic eruptions on the planet. Low-δ18O silicic magmas (δ18O 800 °C) and dry silicic magmas. The relative scarcity of low-δ18O silicic magmas on Earth compared to normal- and high-δ18O magmas implies that coincidence of these factors is rare, and is most likely encountered in hotspot and rift settings characterized by bimodal basaltic-rhyolitic volcanism. Low-δ18O silicic magmas are usually generated by bulk assimilation of rocks that were hydrothermally altered at high temperatures (>300 °C) by isotopically light meteoric water, prevalent at mid to high latitudes and altitudes and/or linked to global glaciation episodes in Earth’s history. We estimate that

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地球上低δ18O 硅质岩浆：综述

摘要 硅质岩浆在大陆地壳的形成中起着重要作用，并且是地球上一些最危险的火山爆发的原因。低δ18O 硅质岩浆（δ18O 800 °C）和干硅质岩浆。与正常和高 δ18O 岩浆相比，地球上低 δ18O 硅质岩浆的相对稀缺意味着这些因素的重合是罕见的，并且最有可能在以双峰玄武质-流纹质火山活动为特征的热点和裂谷环境中遇到。低 δ18O 硅质岩浆通常是由同位素轻的大气水在高温（>300°C）下热液改变的岩石大量同化产生的，在中高纬度和海拔地区普遍存在和/或与地球上的全球冰川作用有关。历史。我们估计