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.

阿拉斯加是美国活火山最多的地区，也是世界上火山最活跃的地区之一。 阿拉斯加的大多数火山形成一个带，包括阿留申群岛，并向陆地延伸到阿拉斯加半岛，从安克雷奇跨越库克湾结束。 阿拉斯加半岛拥有20多座火山，其中5座在过去25年中发生过大规模喷发，包括20世纪世纪世界上最大的火山喷发。 本项目将调查阿拉斯加半岛火山系统的增长情况，并评估影响该地区火山组成和活动的因素。 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正在进行的工作，以了解该地区的火山活动，每天约有30，000人乘坐商用飞机飞越火山，火山爆发可能对安克雷奇（阿拉斯加最大的人口中心）沿着基奈半岛产生严重影响。 阿拉斯加半岛也是全国最重要的矿产资源区之一;该项目将提供一个改进的区域框架，有助于今后详细研究划定经济矿藏。 通过这一项目取得的科学进步也将有助于克拉克湖和卡特迈国家公园的公众宣传使命，本研究中的几座火山就位于这两个国家公园。 该项目还将为本科生提供高水平的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公开提供的样本收集，建立在过去对联邦资金的投资基础上。阿拉斯加南部是世界上研究会聚边缘沿着长期岩浆活动和地壳生长的最佳地点之一，这一点得到GeoPRISMS社区的认可，该社区选择阿拉斯加/阿留申俯冲带作为俯冲周期和变形倡议的最高优先地点。 这个为期两年的项目将使GeoPRISMS社区受益，进行前所未有的天气研究，以评估阿拉斯加半岛第四纪火成岩中始新世的时间和沿走向地球化学趋势。 数据将包括火山岩和深成岩的主元素和微量元素、全岩Nd-Sr-Hf和锆石Hf同位素、40 Ar/39 Ar和锆石U/Pb定年。 这项研究的结果将提供阿留申岛弧大陆部分的新的制约因素，包括：i）沿弧岩浆化学的趋势和与沉积物通量和区域构造的关系，ii）随着时间的推移，俯冲的地球化学产物，以及这些如何影响新的大陆地壳的组成，和iii）俯冲开始的时间和关系，以太平洋与局部构造过程。 这项工作与GeoPRISMS SCD倡议一致，以“侧重于长期边缘演变和物质转移”以及“火山弧和大陆的增长和演变”，并可与其他项目（即，地球物理研究的阿拉斯加南部边缘），以产生在了解收敛边缘岩浆活动的区域控制的进展。