Volcanic Time Scales, Eruption Rates, and Compositional Diversity at a Continental Arc

大陆弧的火山时间尺度、喷发率和成分多样性

• 批准号: 0409052
• 负责人: Rebecca Lange
• 金额: $ 28.8万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0409052&HistoricalAwards=false
• 关键词: Volcanic; Time; Scales; Eruption; Rates

This project, jointly supported by the Petrology and Geochemistry (EAR) and the Americas Programs (INT, is to perform an intensive 40Ar/39Ar dating study, coupled with quantitative estimates of erupted volumes, to fully characterize the volcanic history of three large central volcanoes in western Mexico and their surrounding peripheral vents. This proposed study would extend coverage of the total volcanic output (= 1 Ma) along a continuous 200 km arc segment, which is crucial in addressing global questions regarding the role of different subduction parameters on the eruptive output at arcs. In addition, new data on the eruptive history at individual volcanic fields significantly enhances geochemical and petrological data sets and allows more robust tests of the mechanisms and timescales for magma differentiation. The results of our proposed 40Ar/39Ar dating program will assist in the creation of volcanic hazards maps (independently, by Mexican scientists) in the proposed study area, which is the site of at least six, highly-explosive eruptions in the last 1 Myr, all from vents within = 40 km of Tepic, the capital of the state of Nayarit. Our collaboration with Dr. Hugo Delgado-Granados, from the Universidad Nacional Autonoma de Mexico (UNAM), has led to an extensive exchange of expertise and facilities between the University of Michigan and UNAM, as well as a series of student field trips that alternate between the U.S. and Mexico every other year. This project will provide training to two Ph.D. students (one female/one male), who will become skilled in Ar chronology, volcanic petrology, field mapping, and GIS (Geographic Information System) software tools.

该项目由岩石与地球化学（EAR）和美洲项目（INT）联合支持，将进行密集的40Ar/39Ar定年研究，并结合喷发量的定量估计，以全面表征墨西哥西部三座大型中央火山及其周围火山口的火山历史。这项拟议的研究将扩大沿连续200公里弧段的总火山输出（= 1 Ma）的覆盖范围，这对于解决有关不同俯冲参数对弧段喷发输出的作用的全球性问题至关重要。此外，关于单个火山场喷发历史的新数据显著增强了地球化学和岩石学数据集，并允许对岩浆分化的机制和时间尺度进行更可靠的测试。我们提议的40Ar/39Ar测年计划的结果将有助于在提议的研究区域创建火山危险地图（由墨西哥科学家独立完成），该研究区域是过去1世纪至少6次高爆炸性喷发的地点，所有喷发都来自纳亚里特州首府Tepic = 40公里内的喷口。我们与墨西哥国立自治大学（UNAM）的Hugo Delgado-Granados博士合作，促进了密歇根大学和墨西哥国立自治大学之间的专业知识和设备的广泛交流，以及每隔一年在美国和墨西哥之间交替进行的一系列学生实地考察。本项目将培养两名博士研究生（男女各一），熟练掌握Ar年代学、火山岩石学、野外测绘和GIS（地理信息系统）软件工具。