Collaborative Research: Late Tertiary Silicic Volcanism in Eastern Oregon: Mirror Image to the Yellowstone Hot Trend

P.I.研究沿高熔岩平原10-5 Ma的硅质火山活动段。第一阶段是全面的填图和高精度的40Ar-39Ar定年研究，辅以主要是硅质火山岩的勘察地球化学分析。如有必要，稍后阶段将致力于硅质火山岩的岩石学演化。其基本目的是：(1)详细研究硅质火山活动向西北方向的区域年龄演化，并研究硅质中心内的年龄演化趋势是否与区域趋势相似；(2)通过对年代和(或)地层控制的样品进行地球化学分析，评估硅质火山岩的组成随时间和空间的变化。这将提供一系列独特的时间组成切片，贯穿硅质火山省的演化，并将成为与蛇河-黄石趋势沿线的硅质火山作用进行比较的基础。

The P.I.s to study the 10- to 5-Ma segment of silicic volcanism along the High Lava Plains. The first stage, the subject of this project, is a comprehensive mapping and high- precision 40Ar-39Ar dating study, supplemented by reconnaissance geochemical analyses of mainly the silicic volcanic rocks. A later stage will be aimed at the petrologic evolution of the silicic volcanic rocks, as warranted. The principle aims are: (1) to examine in detail the regional northwestward age progression of silicic volcanism, and to investigate whether age-progressive trends within silicic centers mimic the regional trend; and (2) to evaluate the composition of the silicic volcanic rocks as a function of space and time by geochemical analyses of date and (or) stratigraphically controlled samples. This will provide an unique series of time-composition slices through the evolution of a silicic volcanic province and will be a foundation for comparison to silicic volcanism along the Snake River-Yellowstone trend.