Piston-cylinder apparatus

要求研究工具和仪器赠款购买一个活塞-气缸装置，用于高压（P）-高温（T）实验，以模拟深地幔岩浆从上地幔（深度> 100公里）的源头上升过程中的条件。金伯利岩岩浆将钻石和其他地幔矿物如石榴石、钛铁矿、铬铁矿带到地表。所有这些矿物表现出各种各样的表面特征归因于与金伯利岩岩浆的反应。笔者的实验结果表明，金伯利岩岩浆的温度、磷、氧化态等条件决定了金刚石的保存程度，而金刚石表面溶解的性质则取决于岩浆流体的H_2O/CO_2比值。因此，金刚石的表面特征可以用来推导出寄主金伯利岩的流体成分。该研究将为研究含金刚石岩浆的流体系统及其侵位条件提供新的方法。进一步的校准需要在更大的T-P范围内进行实验，并考虑其他挥发物（例如氯）。当应用于天然钻石包裹体时，该方法将对金伯利岩的起源和演化提出新的约束。金伯利岩中石榴石、铬铁矿和钛铁矿的溶解形式可以提供另一种约束金伯利岩流体成分的方法，该方法可以用于预测金伯利岩管中金刚石的质量。实验将研究这些矿物和金伯利岩岩浆之间的反应，以确定是什么产生了不同的溶解特征：流体成分，岩浆条件或金伯利岩熔体的成分。与钻石相比，这些矿物的复杂化学成分及其相对丰度允许研究金伯利岩流体随深度和时间的演化。该项目将开发研究幔源岩浆流体系统和预测金伯利岩管中金刚石质量的工具。

The Research Tools and Instruments Grant is requested to purchase a piston - cylinder apparatus for high pressure (P) - temperature (T) experiments that simulate conditions during the ascent of deep mantle magma from its source in the upper mantle (> 100 km depth). Kimberlite magmas bring to the surface diamonds and other mantle minerals such as garnets, ilmenites, chromites. All these minerals exhibit variety of surface features attributed to a reaction with the kimberlite magma. My previous experimental results showed that the conditions of kimberlite magma (T, P, oxidation state) determine the degree of diamond preservation, whereas the character of surface dissolution on diamonds depend on H2O/CO2 ratio of the magmatic fluid. Therefore, surface features of diamonds can be used to derive the fluid composition of the host kimberlite. The proposed research will develop a new method for investigating fluid system of diamond-bearing magmas and conditions during their emplacement. Further calibration requires experiments over larger T - P range and taking into consideration other volatiles (e.g. chlorine). When applied to natural diamond parcels this method will put new constraints on origin and evolution of kimberlites. Dissolution forms on kimberlite-hosted garnets, chromites and ilmenites can provide another way to constrain composition of kimberlitic fluid, that can be used for predicting the quality of diamonds in a kimberlite pipe. The experiments will study reaction between these minerals and kimberlite magma to determine what produces the different dissolution features: fluid composition, magma conditions, or composition of kimberlite melt. Complex chemical composition of these minerals and their relative abundance, compared to diamonds, allows investigating evolution of kimberlitic fluid with depth and time. The project will develop tools for studying fluid system of mantle-derived magmas and for predicting diamond quality in kimberlite pipes.