Collaborative Research: 10Be and 9Be in Volcanic Arc Lavas: Investigation of Sediment Recycling

最近对来自不同地质环境的约250个火山岩中Be-10的测量表明，在千岛群岛、阿留申群岛、中美洲、秘鲁-智利和新不列颠弧中，年轻的近地表海洋沉积物被俯冲并合并到弧岩浆中。be -10数据与地球物理和会聚边缘的构造研究相结合表明，沉积物可能在俯冲板块的地堑中俯冲，因为在上层沉积物厚度与下沉盆地的垂直位移近似相等的地方，弧熔岩的be -10浓度最高。宾夕法尼亚大学的加速器最近得到了改进，可以对更小的样品进行更精确的分析，卡内基大学最近购置了一台icp光谱仪，可以对be -9进行测量。该项目旨在测量矿物分离物、新火山弧熔岩和现有样品子集的Be-10/Be-9比率以及Sr、Nd和Pb同位素组成。在可能的情况下，将把结果与其他地球化学研究结合起来，并在地球物理研究的背景下进行评价，以便得出火山弧沉积物俯冲和再循环的综合模型。

Recent measurements of Be-10 in ~250 volcanic rocks from various geologic settings indicate that that young, near-surface oceanic sediments are subducted and incorporated in arc magmas in the Kurile, Aleutian, Central America, Peru-Chile and New Britain arcs. Integration of Be-10 data with geophysical and structural studies of convergent margins suggests that sedfiments may be subducted in grabens in the subducting plate, as Be-10 concentrations an arc lavas are highest where the pelagic sediment thickness approximately equals vertical displacement of the down- dropped basins. Recent improvements in the University of Pennsylvania accelerator permit smaller samples to be analyzed more precisely, and the recent acqusition of an I.C.P. spectrometer at Carnegie permits measurement of Be-9. This project is to measure Be-10/Be-9 ratios and Sr, Nd and Pb isotopic compositions for mineral seperates, new volcanic arc lavas, and a subset of the existing sample collection. Wherever possible results will be combined with other geochemical studies and evaluated in the context of geophysical studies in order to arrive at an integrated model of sediment subduction and recycling at volcanic arcs.