MORB Construction Processes: Plutonic to Volcanic Connections in Plagioclase Ultraphyric Basalts (PUBs)

大洋中脊玄武岩(MORBs)和相关火山岩的成分是用于阐明最终导致洋壳形成的熔融过程以及全球地球化学循环和板块构造等过程的主要观测数据之一。然而，大多数MORB都被发生在上地幔和洋壳中的过程改变了。为了限制MORB在从地幔到洋壳的停留和运输过程中改变其组成的过程，这项研究将对来自超慢和中等扩张速率的大洋中脊的富含斜长石的MORB进行地球化学和结构研究。这项工作的重点将是斜长-超长玄武岩中的斜长石。这种矿物是一种潜在的丰富的、基本上未被开发的岩浆温度、成分、质量平衡和时间的记录器。分析工作将包括结合现场分析化学和同位素分析技术、分析熔岩的主要和微量元素成分、质地研究、确定微量元素扩散剖面、晶体大小分布和其他方法。这项工作的更广泛的影响是对学生和早期职业生涯的教职员工的支持。

The compositions of mid ocean ridge basalts (MORBs) and related volcanic rocks are one of the primary observational datasets used to illuminate melting processes that ultimately lead to formation of ocean crust and processes like global geochemical cycling and plate tectonics. Most MORB, however, is modified by processes that occur in the upper mantle and oceanic crust. To constrain the processes that modify the composition of MORB during its residence and transit from the mantle through the oceanic crust, this research will carry out a geochemical and textural study of plagioclase-rich MORB from ultra-slow and intermediate spreading-rate mid ocean ridges. The focus of the work will be on plagioclase from plagioclase-ultraphyric basalts. This mineral is a potentially rich and largely unexploited recorder of magma temperature, composition, mass balance and time. Analytical work will include a combination of in situ analytical chemical and isotopic analysis techniques, analyses of major and trace element compositions of the lavas, textural studies, determination of trace element diffusion profiles, crystal size distributions, and other approaches. Broader impacts of the work are support of a student and an early career faculty member.