Experimental Geochemical Studies of Solid-Melt Mass Transport Processes Beneath Mid-Ocean Ridges

9731506格罗夫这项工作将涉及旨在了解活跃的海洋扩张中心之下地幔融化过程的条件和时间尺度的实验研究。实验将测定稀土、高场强和大离子亲石元素在高压(1~3 Gpa)和温度(1250oC-1500oC)条件下在石榴石和高钙单斜辉石中的扩散速率。这些都是大洋中脊之下地幔融化的相关条件。实验结果将被用来估计熔体产生过程的时间尺度和类型。为了推断熔融过程的本质，我们将分析熔融产物(大洋中脊玄武岩)和熔体提取后留下的固体残留物(深海橄榄岩)中的元素丰度。实验结果和天然样品中的元素丰度将被用作熔体产生模型的输入。这些熔化模型中的主要未知数是元素的固态扩散速率，它将由实验提供。

9731506 Grove This work will involve experimental studies aimed at understanding the conditions and time scales of mantle melting processes beneath active ocean spreading centers. The experiments will determine diffusion rates of rare earth, high field strength and large-ion lithophile elements in garnet and high-Ca clinopyroxene at elevated pressure (1 to 3 GPa) and temperature (1250oC - 1500oC) conditions. These are the conditions relevant for mantle melting beneath mid-ocean ridges. The results of the experiments will be used to estimate the time scales and styles of melt generation processes. To infer the nature of the melting processes we will analyze the element abundances in the products of melting (mid-ocean ridge basalts) and the solid residues left behind after melt extraction (abyssal peridotites). The experimental results and the element abundances in the natural samples will then be used as input to models of melt production. The primary unknown in these melting models is the solid state diffusion rates for the elements, which will be provided by the experiments.