"Silicic magma chambers, explosive volcanism, and a remarkable tectonic control on the ""Earth System"""

“硅质岩浆库、爆发性火山活动以及对“地球系统”的显着构造控制”

• 批准号: 262856-2012
• 负责人: Jellinek, Andrew
• 金额: $ 2.77万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=571291
• 关键词: Silicic; magma; chambers; explosive; volcanism

I propose a program in three distinct research areas. The first two share a common theme that is explosive volcanism and are motivated by two questions: 1) Why do volcanoes and magma chambers erupt explosively? and, 2) Are there rigorous and reliable ways to forecast volcanism that is dangerous to humans? From an observational perspective, a crucial step towards addressing the first question is to characterize the long-term behavior of magmatic systems that have a history of volcanic activity. A roadblock to building and understanding such a data set, however, is that these systems evolve over million year time scales. Thus, key time series data must be uniquely inferred from textural and chemical data preserved in fossil magma chambers and prehistoric pyroclastic deposits, which is challenging. To this end, we develop a rigorous field- and mineral chemistry-based methodology that enables us to identify key magmatic processes in geological data, as well as their evolution prior to eruption. To address the second question, we turn to real-time observations of pre-eruptive seismic tremors. We extend our preliminary model that predicts the character of this oscillation prior to dangerous eruptions to make testable predictions also for tremor amplitude and related effects such as magmatic gas flux and ground deformation. This work will provide a new reliable tool for forecasting explosive eruptions. The third research area explores provocative implications of a remarkable prediction that the mantle thermal regime during supercontinental cycles will cause basalt crustal production to virtually cease. Extensive hydration of mantle (rather than crustal) rocks will, in turn, produce massive fluxes of methane and hydrogen into the deep ocean. This work proposes a fundamental tectonic control on the long-term variability of the chemistry and biology of the oceans, as well as on surface climate.

我提出了三个不同研究领域的计划。前两个主题有一个共同的主题，即爆发性火山活动，并由两个问题引发：1）为什么火山和岩浆室会爆发性喷发？ 2）是否有严格可靠的方法来预测对人类有害的火山活动？从观测的角度来看，解决第一个问题的关键一步是描述具有火山活动历史的岩浆系统的长期行为特征。然而，构建和理解此类数据集的一个障碍是这些系统的演变超过百万年的时间尺度。因此，关键时间序列数据必须从化石岩浆房和史前火山碎屑沉积物中保存的结构和化学数据中独特地推断出来，这是具有挑战性的。为此，我们开发了一种严格的基于现场和矿物化学的方法，使我们能够识别地质数据中的关键岩浆过程及其在喷发前的演化。为了解决第二个问题，我们转向对爆发前地震的实时观测。我们扩展了预测危险喷发之前这种振荡特征的初步模型，以便对震颤幅度和相关影响（例如岩浆气体通量和地面变形）做出可测试的预测。这项工作将为预测爆炸性喷发提供一种新的可靠工具。第三个研究领域探索了一个引人注目的预测的挑衅性含义，即超大陆循环期间的地幔热状态将导致玄武岩地壳生产几乎停止。地幔（而不是地壳）岩石的广泛水合作用反过来会产生大量甲烷和氢气进入深海。这项工作提出了对海洋化学和生物学以及地表气候的长期变化的基本构造控制。