Collaborative Research: Combined Electron/Ion Microprobe Study of the Composition of the Deep Continental LithosphereBeneath the Colorado Plateau and Adjoining Regions

该项目将重点关注科罗拉多高原和邻近地区，在那里推断出元古宙时期的橄榄岩根延伸到大约80-100公里的深度，周围是裂陷的大陆岩石圈。在科罗拉多高原内外的火山岩中发现了丰富的上地幔样本，这些捕虏体中的一些矿物相记录了岩石圈最近的组成历史。矿物相的微量元素丰度（REE,Ti,Zr,Hf,Sr）将用于推断岩石圈整体组成的垂直和横向变化，最近岩浆或交代事件所涉及的阶段的性质，与这些事件相一致的任何微量元素分馏（例如REE/HFSE）的性质。而这些事件发生的时间是通过对分区剖面的建模得出的。主要的分析工具将是离子和电子探针，用于痕量和主要元素的原位分析。

This project will focus on the Colorado Plateau and adjoining regions where an inferred Proterozoic-aged, peridotite root extends to a depth of approximately 80-100 km and is surrounded by rifted continental lithosphere. Abundant samples of the upper mantle occur in volcanic rocks on and off the Colorado Plateau, and some mineral phases in these xenoliths record the recent compositional history of the lithosphere. Trace element abundances (REE,Ti,Zr,Hf,Sr) of mineral phases will be used to deduce the variation in the bulk composition of the lithosphere vertically and laterally, the nature of the phases involved in recent magmatic or metasomatic events, the nature of any trace element fractionations (e.g., REE/HFSE) coincident with these events, and the timing of these events from modelling of zoning profiles. Principal analytical tools will be the ion and electron microprobes for in situ analysis of trace and major elements.