Volcanic Hazard Assessment in the Southwestern US Based on High-precision Ar/Ar Geochronology of Late Quaternary Eruptive Centers

基于晚第四纪喷发中心高精度 Ar/Ar 地质年代学的美国西南部火山危害评估

• 批准号: 1322089
• 负责人: Matthew Zimmerer
• 金额: $ 19.78万
• 依托单位: New Mexico Institute of Mining and Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1322089&HistoricalAwards=false
• 关键词: Volcanic; Hazard; Assessment; Southwestern; US

The goal of the proposed research is to assess the volcanic hazards in the southwestern US by establishing the periodicity and temporal-spatial patterns of late Quaternary (i.e., 500,000 yrs) volcanism in the region. One of the fundamental components of volcanic hazard assessment is determining the timing and location of previous eruptions. The location of young eruptive centers in the southwestern US is well established. However, the existing geochronology for these volcanoes is not sufficiently precise or complete for an accurate hazard assessment. Ultra-high precision Ar/Ar ages will be generated for Quaternary volcanic rocks using state of the art mass spectrometers. Ages will be used to calculate eruption recurrence and repose intervals, and magma supply rates. A comprehensive age-based assessment of volcanic hazards will be generated for the region. Information regarding volcanic hazards for the southwestern US will be made available to government agencies and the general public through a variety of outreach activities.The central theme to the proposed research is using geochronology to develop a comprehensive understanding of volcanic hazards in the southwestern US. Recent acquisition and development of two low-volume, high-sensitivity, multicollector ARGUS VI mass spectrometers at the New Mexico Geochronology Research Laboratory routinely yield ages that are about an order of magnitude more precise than previous noble gas mass spectrometers. With these analytical improvements, the temporal-spatial patterns of late Quaternary volcanic systems can be characterized at a level that was previously unobtainable. Initial efforts will focus on the numerous basaltic centers and sparse silicic domes in the Rio Grande Rift and Jemez Lineament within New Mexico. Some of these centers, especially those 50 ka, have been dated by other methods providing a means to assess the accuracy of our ages. In addition to assessing volcanic hazards, the ultra-high precision ages will likely be useful for understanding the evolution of the Rio Grande Rift, crust-mantle dynamics, and landscape evolution of the southwestern US.

拟议的研究的目的是通过确定该地区晚期（即500,000年）火山的周期性和时间空间模式来评估我们西南部的火山危害。火山危害评估的基本组成部分之一是确定先前喷发的时间和位置。美国西南部的年轻喷发中心的位置已良好。但是，这些火山的现有地年代学不足以精确或完全完整，以进行准确的危害评估。使用最先进的质谱仪为第四纪火山岩生成超高精度的AR/AR年龄。年龄将用于计算喷发复发和安息间隔以及岩浆供应率。该地区将对该地区进行基于年龄的综合评估。有关西南美国火山危害的信息将通过各种外展活动向政府机构和公众提供。拟议的研究的中心主题是利用地年代学来对我们西南部的火山危害进行全面的了解。在新墨西哥州地球人工学研究实验室通常会产生比以前的贵族气体质谱器更精确的阶数，在新墨西哥州地球人工学研究实验室的最新获取和开发是在新墨西哥州地球人工学研究实验室中的两个小批量，高敏化的多积分质量光谱仪。通过这些分析改进，可以在以前无法获得的水平上表征晚期火山系统后期的时间空间模式。最初的努力将集中在新墨西哥州里奥格兰德裂谷和杰梅斯线的众多玄武岩中心和稀疏的硅胶圆顶上。这些中心中的一些，尤其是50 ka，已经通过其他方法来定位，这些方法提供了一种评估我们年龄准确性的方法。除了评估火山危害外，超高的精度年龄可能有助于理解里奥格兰德裂谷，西南我们西南部的里奥格兰德裂谷，地壳甲壳虫动力学和景观演变。