Nb/Ta-U/Pb and Th/Pb fractionation in rutile-bearing veins from the Dabie Shan ultrahigh pressure metamorphic belt

我们打算研究著名的大别山-苏鲁变质带高压榴辉岩主岩中形成的矿脉。特别是，我们将尝试模拟和平衡榴辉岩寄主和脉体组合中的微量元素平衡，以得出(A)流体成分的变化，以及(B)脱水后残留榴辉岩的成分。我们将特别强调HFSE的质量平衡和元素分馏，例如Nb/Ta，Sm/Nd，Rb/Sr，U/Pb和Th/Pb。这些比值对于评估俯冲过程中Nb/Ta的变化以及高压流体对地球储集层中同位素系统的可能影响至关重要。

We intend to study veins that formed in eclogitic host rocks under high pressure in the famous Dabie Shan-Sulu metamorphic belt. In particular, we will attempt to model and balance trace element budgets in eclogite host and vein assemblage to derive (a) changing fluid compositions, and (b) the composition of the residual eclogite left after dehydration. We will place particular emphasis on the HFSE mass balance and elemental fractionation of, e.g. Nb/Ta, Sm/Nd, Rb/Sr, U/Pb, and Th/Pb. These ratios are critical in evaluating the Nb/Ta variation during subduction processes as well as possible effects of high-pressure fluids on isotopic systems in Earth's reservoirs.