RUI: Magmatic Evolution Leading Up to the Modern Aleutian Arc on the Alaska Peninsula

RUI：导致阿拉斯加半岛现代阿留申岛弧的岩浆演化

• 批准号: 1456630
• 负责人: Ronald Cole
• 金额: $ 10.73万
• 依托单位: Allegheny College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1456630&HistoricalAwards=false
• 关键词: RUI; Magmatic; Evolution; Leading; Up

Alaska contains the largest number of active volcanoes in the United States and is one of the most volcanically active regions in the world. Most of the volcanoes in Alaska form a belt that includes the Aleutian Islands and extends landward onto the Alaska Peninsula, ending across the Cook Inlet from Anchorage. The Alaska Peninsula hosts more than 20 volcanoes with historic activity, five with major eruptions in the past 25 years, and includes the world's largest eruption of the 20th century. This project will investigate the growth of the volcanic system on the Alaska Peninsula and evaluate the factors that influence the composition and behavior of volcanoes in this region. The results of this project will contribute to ongoing work of the U.S. Geological Survey and Alaska Volcano Observatory for understanding volcanic behavior in a region where there are roughly 30,000 people per day transported in commercial aircraft over the volcanoes and where eruptions can have severe impact on Anchorage (Alaska's largest population center) and along the Kenai Peninsula. The Alaska Peninsula is also one of the nation's most important mineral resource regions; this project will provide an improved regional framework that will be useful for future detailed studies to delineate economic mineral deposits. Scientific advances made through this project will also contribute to the public-outreach mission of Lake Clark and Katmai National Parks, where several of the volcanoes of this study are located. This project will additionally provide high-level STEM training for undergraduate students. The project is highly cost-effective because it uses publically-available sample collections of the U.S. Geological Survey, building on past investments in federal funding. Southern Alaska is one of the best places in the world to investigate long-term magmatism and crustal growth along a convergent margin, as recognized by the GeoPRISMS community who selected the Alaska/Aleutian subduction zone as the highest priority site for the Subduction Cycles and Deformation (SCD) initiative. This two-year project will benefit the GeoPRISMS community with an unprecedented synoptic study to evaluate temporal and along-strike geochemical trends for Eocene through Quaternary igneous rocks on the Alaska Peninsula. Data will include major and trace element, whole rock Nd-Sr-Hf and zircon Hf-isotopes, and 40Ar/39Ar and zircon U/Pb dating on volcanic and plutonic rocks. The results of this research will provide new constraints on the continental portion of Aleutian arc including: i) along-arc trends in magma chemistry and relationships with sediment flux and regional tectonics, ii) geochemical products of subduction over time and how these influence the composition of new continental crust, and iii) the timing of subduction initiation and relationship to Pacific-wide versus local tectonic processes. This work is in concert with the GeoPRISMS SCD initiatives to "focus on long-term margin evolution and material transfer" and "the growth and evolution of volcanic arcs and continents" and can be integrated with other projects (i.e., geophysical studies of the southern Alaska margin) to yield advances in understanding the regional controls on convergent margin magmatism.

阿拉斯加拥有美国数量最多的活火山，是世界上最具火山活动的地区之一。 阿拉斯加的大多数火山都形成了一条腰带，其中包括阿留申群岛，并将陆地延伸到阿拉斯加半岛，从安克雷奇（Anchorage）穿过厨师入口。 阿拉斯加半岛拥有20多个具有历史性活动的火山，在过去25年中进行了5次大规模爆发，其中包括20世纪世界上最大的喷发。 该项目将研究火山系统在阿拉斯加半岛上的生长，并评估影响该地区火山组成和行为的因素。 该项目的结果将有助于美国地质调查局和阿拉斯加火山观测站的持续工作，以了解一个在一个在火山上每天大约有30,000人运输的地区，在该地区，大约有30,000人在火山上运输，而爆发可能会对锚定（阿拉斯加最大的人口中心）以及凯纳奈半岛施加严重影响。 阿拉斯加半岛也是美国最重要的矿产资源地区之一。该项目将提供一个改进的区域框架，这将对于未来的详细研究来描述经济矿藏。 通过该项目取得的科学进步还将为克拉克湖和卡特梅国家公园的公共构造任务做出贡献，该任务是该研究的几个火山所在的地方。 该项目还将为本科生提供高级STEM培训。 该项目具有很高的成本效益，因为它使用了美国地质调查局的公开样品收集，这是基于过去对联邦资金投资的投资。阿拉斯加南部是世界上最好的地方之一，沿着融合边缘进行长期岩浆和地壳生长，这是被地理化主义社区所认可的，他们选择了阿拉斯加/阿留申俯冲带作为俯冲循环和变形（SCD）主动性的最高优先位点。 这个为期两年的项目将通过一项前所未有的概要研究使地理流行主义社区受益，以评估始世于阿拉斯加半岛上的四级火成岩的时间和局势地球化学趋势。 数据将包括主要和痕量元素，整个岩石ND-SR-HF和锆石HF - 同位素，以及在火山和丘脑岩石上约会的40AR/39AR和锆石U/PB。 The results of this research will provide new constraints on the continental portion of Aleutian arc including: i) along-arc trends in magma chemistry and relationships with sediment flux and regional tectonics, ii) geochemical products of subduction over time and how these influence the composition of new continental crust, and iii) the timing of subduction initiation and relationship to Pacific-wide versus local tectonic processes. 这项工作与Geoprisms SCD倡议一致，以“关注长期的边距演化和材料转移”和“火山弧和大陆的生长和进化”，并可以与其他项目（即南部阿拉斯加地区的地球物理学研究）集成，以了解对收敛型磁岩的区域控制的收益率。