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

该项目由岩石学和地球化学（PGE）和美洲计划（INT）联合支持，将进行深入的40 Ar/39 Ar定年研究，并对喷发量进行定量估计，以充分描述墨西哥西部三座大型中央火山及其周边喷口的火山历史。 这项拟议的研究将扩大覆盖面的总火山产出（= 1百万年）沿沿着一个连续的200公里弧段，这是至关重要的，在解决全球性的问题，不同的俯冲参数的作用，在弧的喷发输出。 此外，关于个别火山区喷发历史的新数据大大增强了地球化学和岩石学数据集，并允许对岩浆分异的机制和时间尺度进行更有力的测试。 我们提出的40 Ar/39 Ar测年计划的结果将有助于创建火山危险地图（独立，由墨西哥科学家）在拟议的研究领域，这是至少六个网站，高度爆炸性的喷发在过去的100万年，所有的喷口= 40公里的特匹克，首都的纳亚里特。 Hugo Delgado-Granados，从墨西哥国立自治大学（UNAM），导致了密歇根大学和UNAM之间的专业知识和设施的广泛交流，以及一系列的学生实地考察，交替之间的美国和墨西哥每隔一年。 该项目将为两名博士提供培训。学生（一名女性/一名男性），他们将熟练掌握Ar年代学、火山岩石学、野外制图和GIS（地理信息系统）软件工具。

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.