Collaborative Research: What lies beneath: An investigation of subglacial silicic magma systems (Vatnajokull, Iceland)

合作研究：底层是什么：冰下硅质岩浆系统的调查（冰岛瓦特纳冰原）

• 批准号: 2219431
• 负责人: Tenley Banik
• 金额: $ 21.17万
• 依托单位: Board of Trustees of Illinois State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2219431&HistoricalAwards=false
• 关键词: Collaborative; Research; What; lies; beneath

Iceland is positioned where a mid-ocean ridge and a mantle plume intersect at high latitude, resulting in dynamic and dangerous volcano-ice interactions. Two of Iceland’s four most historically active volcanoes (Grímsvötn and Bárðarbunga) occur near the intersection of the ridge and plume, but they are largely obscured from view by Vatnajökull, an ice cap that covers ~10% of Iceland’s surface area. There are indications that glacial retreat can lead to increased eruption rates by destabilizing existing magma bodies and even prompting new magma generation. As climate continues to change and Iceland’s ice caps continue to thin, there is increasing concern about the impacts on subglacial volcanic systems and their associated hazards. It is important to better understand past and present behavior of subglacial volcanic systems to better prepare for future volcanic threats. The primary objective of this study is to explore the origin, evolution, age, and longevity of magmas under Vatnajökull in order to better understand Iceland’s glacio-volcanic hazard potential, while simultaneously learning about a geologically unique part of the world. This work will strengthen existing, and facilitate new, collaborations with domestic and international scientists in the field and in analytical labs. It will also create opportunity for community engagement and public education, and provide rigorous research experiences for 6+ undergraduate students, a majority of whom are from traditionally under-represented backgrounds.In Iceland, silicic material accounts for ~10% of the exposed crust; at central volcanoes, this amount increases to ~30%. Volcanic systems beneath Vatnajökull appear to have a paucity of silicic material relative to their subaerial counterparts. This may be a consequence of the proximity to the ridge-plume intersection, or (more likely) a consequence of poor exposure leading to sample bias. Since silicic magmas have the potential to erupt more explosively and with greater associated hazards than basaltic magmas, it is important to understand the role they may play at the productive, active, systems obscured from view by Vatnajökull. The research questions to be investigated are: To what extent are silicic materials associated with Bárðarbunga, Grímsvötn, and neighboring Kverkfjöll? Are collected silicic materials from active magmatic systems, older bedrock, or a combination? How do the geochemical characteristics of these systems’ silicic materials compare to those in the known rock record elsewhere in Iceland? What hazards do silicic magmas present in this dynamic rift-mantle plume-ice environment? Data generated in this study will facilitate mapping the regional distribution of subglacial silicic materials (both those associated with active volcanic systems and those from older bedrock). Evidence from nunatak and moraine rocks (major and trace elements; Hf, Nd, and Pb isotopes; petrography) and their accessory minerals (zircon: U-Th and U-Pb dates, O and Hf isotopes, trace elements; apatite: trace elements, volatiles) will make it possible to decipher the petrogenetic origins and evolution of silicic systems at Iceland’s most plume-affected, and most active, central volcanoes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

冰岛位于洋中脊和地幔柱在高纬度相交的地方，导致冰岛历史上最活跃的四座火山中的两座（格里姆斯火山和巴尔扎本加火山）发生在洋中脊和地幔柱交汇处附近。 ，但它们在很大程度上被瓦特纳冰川覆盖，覆盖了冰岛约 10% 的表面积。有迹象表明。冰川退缩会破坏现有岩浆体的稳定性，甚至促使新的岩浆生成，从而导致喷发率增加。随着气候持续变化和冰岛冰盖持续变薄，人们越来越担心其对冰下火山系统的影响及其相关危害。对于更好地了解冰下火山系统过去和现在的行为以更好地应对未来的火山威胁非常重要。这项研究的主要目的是探索冰下火山系统的起源、演化、年龄和寿命。瓦特纳冰川下的岩浆，以便更好地了解冰岛的冰川火山灾害潜力，同时了解世界上独特的地质部分。这项工作将加强与该领域和分析实验室的国内外科学家的现有合作，并促进新的合作。它还将为社区参与和公共教育创造机会，并为 6 岁以上本科生提供严格的研究经验，其中大多数来自传统上代表性不足的背景。在冰岛，硅材料占主导地位。约 10% 的裸露地壳；在中央火山，这一数量增加到约 30%，相对于其地下分支，瓦特纳冰川下方的火山系统似乎缺乏硅质物质，这可能是由于靠近山脊​​的结果。羽流交叉，或者（更有可能）是由于暴露不良导致样本偏差的结果，因为硅质岩浆比玄武岩岩浆有可能喷发得更猛烈，并且具有更大的相关危险。了解它们在被瓦特纳冰原所掩盖的生产性、活跃系统中可能发挥的作用非常重要。要调查的研究问题是：硅质材料在多大程度上与巴扎本加、格里姆斯沃特恩和邻近的克韦尔克山有关？来自活跃岩浆系统、较古老的基岩或其组合的硅质物质与已知的物质相比如何？冰岛其他地方的岩石记录？在这种动态裂谷地幔羽冰环境中硅质岩浆存在哪些危险？这项研究中生成的数据将有助于绘制冰下硅质物质的区域分布图（包括与活动火山系统有关的物质和来自较古老的物质）来自努纳塔克和冰碛岩的证据（主量元素和微量元素；Hf、Nd 和 Pb 同位素；岩相学）及其副矿物（锆石： U-Th 和 U-Pb 年代、O 和 Hf 同位素、微量元素；磷灰石：微量元素、挥发物）将有助于破译冰岛受羽流影响最严重、最活跃的中心硅质系统的岩石成因和演化。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。