ROW: Composition and Evolution of the Lower Crust and Crust-Mantle Boundary of the Basin and Range-to-Colorado Plateau Transition Zone

大陆地壳演化模拟需要改进 了解下地壳岩石类型、成分和 结构 盆地和山脉的近期地球物理断面 以及盆地和山脉向科罗拉多高原的过渡 区提出了关于性质和发展的问题， 下地壳和壳幔边界。 盆地和山脉下方的莫霍面地形平坦， 盆地和山脉下方的近水平莫霍面反射体， BR-CP过渡带暗示玄武岩 底托作用在发展中发挥了重要作用， 盆山期下地壳与壳幔边界 新生代伸展 来自亚利桑那州维基厄普的捕虏体提供了 BR-CP过渡带下方的壳幔边界。 该捕虏体套包括丰富的上部复合结核， 地幔橄榄岩与下地壳辉长岩接触， 麻粒岩 完整的岩相和成分分析 （矿物、全岩主要元素、微量元素和稀有元素、同位素） 将用于确定下地壳岩石的成因 类型 捕虏体温压测定法将提供 该地区下地壳的热状态。 将完整的岩石学数据与现有的地球物理数据相结合 数据将允许评估过程的作用，例如 盆山演化中的玄武岩底侵作用 下地壳和壳幔边界的发育。

Modeling of continental crustal evolution requires improved understanding of lower crustal rock types, compositions, and structure. Recent geophysical transects in the Basin and Range and the Basin and Range-to-Colorado Plateau (BR-CP) transition zone have raised questions about the nature and development of the lower crust and the crust-mantle boundary in this region. Flat Moho topography beneath the Basin and Range, and multiple, sub-horizontal Moho reflectors beneath the Basin and Range and the BR-CP transition zone have lead to suggestions that basaltic underplating played an important role in the development of the Basin and Range lower crust and crust-mantle boundary during Cenozoic extension. Xenoliths from Wikieup, Arizona provide actual rock samples from the crust-mantle boundary beneath the BR-CP transition zone. This xenolith suite includes abundant composite nodules of upper mantle peridotite in contact with lower crustal gabbro and granulite. Complete petrographic and compositional analysis (minerals, whole rock major, trace, and rare elements, isotopes) will be used to determine the petrogenesis of lower crustal rock types. Xenolith thermobarometry will provide estimates of the thermal state of the lower crust in this region. Integration of complete petrologic data with existing geophysical data will allow evaluation of the role of processes such as basaltic underplating in the evolution of the Basin and Range lower crust and the development of the crust-mantle boundary.