The Cycling Of Platinum-Group Elements And Rhenium In The Tonga Subduction Zone

这项研究的目的是为了更好地了解铂族元素在下行板脱水和其上方地幔楔熔剂熔融过程中的行为。发生的亲子分馏作用是什么？这些分馏作用如何促进地幔不均质性的形成。由于汤加-刘盆地系统是大洋内的，因此可以避免陆壳造成的复杂情况。将对汤加系和古太平洋地壳中现有的ODP体样品进行Re、Pges和Os同位素加上0和S同位素的分析，这些样品已被表征为其他微量元素和同位素体系。拥有一套具有良好特征的代表性样品应该能够评估俯冲沉积物、蚀变洋壳以及弧形和弧后火山岩中的地幔楔体的相对贡献。

AbstractThe goals of this proposed study are to better understand the behavior of platinum group elements (PGEs) during dehydration of the downgoing slab and flux melting of the mantle wedge above it. What are the parent-daughter fractionations that occur and how do these contribute to creation of mantle heterogeneities. Since the Tonga-Lau basin system is intraoceanic, the complications due to continental crust can be avoided. Analyses of Re, PGEs and Os isotopes plus 0 and S isotopes will be done for existing ODP samples from the Tonga system and old Pacific crust that have been characterized for other trace elements and isotope systems. Having a well-characterized suite of representative samples should allow an assessment of the relative contributions of subducted sediments, altered ocean crust, and the mantle wedge in arc and back arc volcanic rocks.