Collaborative Research: Geochemistry of Ultramafic Xenoliths From the Mantle Wedge of the Kamchatka Arc

这是对位于俄罗斯远东堪察加半岛的三座与俯冲有关的火山中发现的地幔岩石的包体进行的研究。这项研究中感兴趣的岩石类型是方辉橄榄岩和英安岩，它们被下行俯冲板块产生的水化流体或熔体化学改变(交代)，在地幔中产生毫米和厘米级的矿脉和辉石、角闪石或金云石的矿化带。这项研究的目的是了解堪察加和其他俯冲系统中交代过程的性质及其与岩浆成因的关系。该项目涉及收集不同的地球化学数据，包括几个气相和轻元素同位素系统(3He/4He，3He/CO2，13C，18O，D)以及重元素同位素比值(Sr，ND，Pb和Hf)，这些数据在我们理解俯冲-交代过程中发挥了关键作用。ICPMS将对全岩和矿物溶液进行微量元素分析。这些数据将通过对一些高场强元素(Ta、Nb、Zr和Hf)浓度的高精度同位素稀释测量而得到加强。来自罗切斯特大学和南卡罗来纳大学的研究生和本科生将参与数据收集和解释的所有方面。这是罗切斯特大学和南卡罗来纳大学在国内和国际上与俄罗斯堪察加彼得罗巴甫洛夫斯克的俄罗斯火山地质和地球化学研究所合作的项目。

This is a study of mantle-derived rocks found as xenoliths in three subduction-related volcanoes located on the Kamchatka Peninsula in the Russian Far East. The rock types of interest in this study are harzburgites and dunites that have been chemically altered (metasomatized) by hydrous fluids or melts derived from the down-going subducted plate, which produced millimeter and centimeter-scale veins and mineralized zones of pyroxene and amphibole or phlogopite in the mantle. The objective of the study is to understand the nature of the metasomatic process and its relationship to magma genesis in Kamchatka and other subduction systems. The project involves the collection of diverse geochemical data, including several of the gas-phase and light-element isotope systems (3He/4He, 3He/CO2, 13C, 18O, D) as well as heavy-element isotope ratios (Sr, Nd, Pb and Hf) that play a key role in our understanding of subduction-metasomatic processes. Trace element analyses will be done by ICPMS on whole-rock and mineral solutions. These data will be augmented by high-precision, isotope-dilution measurements of some high field strength element (Ta, Nb, Zr and Hf) concentrations. Graduate and undergraduate students from the University of Rochester and the University of South Carolina will be involved in all aspects of the data collection and interpretation. This is a collaborative project, domestically, between the University of Rochester and the University of South Carolina and, internationally, with the Russian Institute of Volcanic Geology and Geochemistry, in Petropavlovsk, Kamchatka, Russia..