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.

拟议研究的目标是通过建立晚第四纪（即， 500，000年）的火山活动。火山灾害评估的一个基本组成部分是确定以前喷发的时间和地点。美国西南部的年轻喷发中心的位置是确定的。然而，这些火山的现有地质年代学不够精确或完整，无法进行准确的危险评估。将使用最先进的质谱仪对第四纪火山岩进行超高精度Ar/Ar年龄测定。年龄将被用来计算喷发复发和休息时间，和岩浆供应率。将对该区域的火山危害进行全面的年龄评估。有关美国西南部火山灾害的信息将通过各种外展活动提供给政府机构和公众。拟议研究的中心主题是利用地质年代学来全面了解美国西南部的火山灾害。最近在新墨西哥州地质年代学研究实验室购置和开发了两台低容量、高灵敏度、多接收器的ARGUS VI质谱仪，它们通常产生的年龄比以前的惰性气体质谱仪精确一个数量级。通过这些分析改进，可以在以前无法获得的水平上表征晚第四纪火山系统的时空模式。最初的工作将集中在格兰德河裂谷和新墨西哥州内的杰梅斯线上的众多玄武岩中心和稀疏的圆顶。其中一些中心，特别是那些50 ka，已经通过其他方法提供了一种手段来评估我们的年龄的准确性。除了评估火山灾害外，超高精度年龄可能有助于了解格兰德河裂谷的演化、壳幔动力学和美国西南部的景观演化。