Collaborative Research: Experimental Determination of the Damp Peridolite Solidus

合作研究：潮湿橄榄岩固相线的实验测定

• 批准号: 1459649
• 负责人: Glenn Gaetani
• 金额: $ 42.35万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459649&HistoricalAwards=false
• 关键词: Collaborative; Research; Experimental; Determination; Damp

The development and application of new experimental approaches that can control key components of a system provide opportunities for breakthroughs; not only for the topic for which the method was developed, but many times also for other systems and disciplines. This research takes a novel, newly developed approach for quantitatively controlling very small amounts of H2O in high temperature/pressure experiments and applies it to one of the most fundamental rock forming processes on the planet: the melting of mantle rocks (peridotite) to form magmas, some of which eventually reach Earth?s surface. Because hydrogen diffuses rapidly into olivine, one of the most common minerals in the Earth?s mantle, the researchers receiving this award are now able to infuse predetermined concentrations of H2O into spheres of olivine about 300 microns in diameter. These olivines are then used as hygrometers in experiments that allow the pressure dependence to be determined of the exact instant when melting of mantle rock begins (i.e., the peridotite solidus). Understanding this fundamental reaction is important because the melting of Earth's mantle (i.e., peridotite) drives the spreading apart of the mid-ocean ridges and has a significant impact on the transfer of mass and heat from Earth?s interior to its surface as well as on the thickness of Earth?s crust.To determine the lherzolite solidus at H2O-undersaturated conditions, partial melting experiments around 1300 C and from 1 to 3 GPa will be conducted using synthetic peridotite containing spheres of San Carlos olivine doped with specified H2O contents. Using the spheres as hygrometers, the olivines will be analyzed by secondary ion mass spectrometry to determine when the H2O content of the olivine changes, indicating the initiating of melting. Research goals are to determine the peridotite solidus and the impact of Na2O and mineral mode on melting. Results will provide the first quantitative experimental determination of the H2O-undersaturated peridotite solidus. Broader impacts of the work include method development and application, thus, building infrastructure for science. It also provides student training at the graduate and undergraduate level. The unique mineralogical hygrometer may also have applications for materials science and other areas where the exact temperature and pressure of a solidus for a material of a specific composition is needed.

能够控制系统关键组件的新实验方法的开发和应用提供了突破的机会；不仅适用于开发该方法的主题，而且多次适用于其他系统和学科。 这项研究采用了一种新开发的新颖方法，在高温/高压实验中定量控制极少量的 H2O，并将其应用于地球上最基本的岩石形成过程之一：地幔岩石（橄榄岩）熔化形成岩浆，其中一些最终到达地球表面。由于氢会迅速扩散到橄榄石（地幔中最常见的矿物之一）中，因此获得该奖项的研究人员现在能够将预定浓度的 H2O 注入直径约 300 微米的橄榄石球体中。然后，这些橄榄石在实验中用作湿度计，可以确定地幔岩石开始熔化的确切瞬间（即橄榄岩固相线）的压力依赖性。了解这一基本反应非常重要，因为地幔（即橄榄岩）的融化推动了大洋中脊的扩张，并对从地球内部到其表面的质量和热量的传递以及为了确定 H2O 不饱和条件下的二辉橄榄石固相线，将使用合成橄榄岩进行 1300 C 左右和 1 至 3 GPa 的部分熔融实验含有掺杂指定 H2O 含量的圣卡洛斯橄榄石球体。 使用球体作为湿度计，通过二次离子质谱法对橄榄石进行分析，以确定橄榄石中的 H2O 含量何时发生变化，表明开始熔化。研究目标是确定橄榄岩固相线以及 Na2O 和矿物模式对熔融的影响。结果将首次对 H2O 不饱和橄榄岩固相线进行定量实验测定。这项工作的更广泛影响包括方法开发和应用，从而建设科学基础设施。它还提供研究生和本科生水平的学生培训。独特的矿物湿度计还可以应用于材料科学和其他需要特定成分材料的精确固相线温度和压力的领域。