Collaborative Research: Redox Processes in Rio Grande Rift and Colorado Plateau Xenoliths

[404819 . McGuire]本研究旨在研究在严格限制的地质背景下共存的地幔矿物的Fe3+， H+和总体组成之间的相互关系。样本将从大裂谷和科罗拉多高原地区选择，这些地区将是美国地质勘探局计划于1995年进行的多学科样带的地点。我们计划表征从选定地点收集的地幔捕虏体中所有共存矿物的Fe3+/ Fe比率和H+，以确定沿样带的地幔氧化还原条件的区域变化。我们还将研究复合地幔包体中的交代氧化还原过程，重点观察隐蔽交代和明显交代的氧化还原差异和相似之处。测定未交代和复合交代捕虏体中所有共存矿物的H+含量；在可能的情况下，还将确定D/H比值，以便更好地了解H+在地幔氧化还原过程中的作用。

9404819 McGuire This research seeks to examine the interrelationships among Fe3+, H+, and bulk composition of coexisting mantle minerals from within a carefully-constrained geologic context. Samples will be selected from Rio Grande rift and Colorado Plateau localities which will be the sites of A U.S.G.S. multidisciplinary transect planned for 1995. We plan to characterize Fe3+/ Fe ratios and H+ of all coexisting minerals in mantle xenoliths collected from the chosen localities, in order to determine regional variations in mantle redox conditions along the transect. We will also study metasomatic redox processes in composite mantle xenoliths with emphasis on observing redox differences and similarities between cryptic and patent metasomatism. H+ contents of all coexisting minerals in both unmetasomatized and composite metasomatized xenoliths will be measured; when possible, D/H ratios will also be determined in order to better understand the role of H+ in mantle redox processes.