Department of Earth and Planetary Sciences, University of California, Davis, Davis, CA 95616, USA.
School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA.
Science. 2017 Jun 16;356(6343):1154-1156. doi: 10.1126/science.aam8720. Epub 2017 Jun 15.
Silicic volcanic eruptions pose considerable hazards, yet the processes leading to these eruptions remain poorly known. A missing link is knowledge of the thermal history of magma feeding such eruptions, which largely controls crystallinity and therefore eruptability. We have determined the thermal history of individual zircon crystals from an eruption of the Taupo Volcanic Zone, New Zealand. Results show that although zircons resided in the magmatic system for 10 to 10 years, they experienced temperatures >650° to 750°C for only years to centuries. This implies near-solidus long-term crystal storage, punctuated by rapid heating and cooling. Reconciling these data with existing models of magma storage requires considering multiple small intrusions and multiple spatial scales, and our approach can help to quantify heat input to and output from magma reservoirs.
硅质火山喷发带来了相当大的危害，但导致这些喷发的过程仍知之甚少。一个缺失的环节是了解为这些喷发提供岩浆的热历史，这在很大程度上控制着结晶度，从而控制着喷发性。我们已经确定了来自新西兰陶波火山区喷发的单个锆石晶体的热历史。结果表明，尽管锆石在岩浆系统中存在了 10 到 100 年，但它们仅经历了 >650°到 750°C 的温度数百年到数千年。这意味着在接近固相线的情况下进行长期的晶体储存，期间伴随着快速的加热和冷却。要使这些数据与现有的岩浆储存模型相协调，就需要考虑多个小侵入体和多个空间尺度，我们的方法可以帮助量化岩浆储层的热量输入和输出。
