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: 1459123
• 负责人: Erik Hauri
• 金额: $ 8.32万
• 依托单位: Carnegie Institution of Washington
• 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 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1459123&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为突破提供了机会；这种方法不仅适用于开发该方法的主题，而且很多时候也适用于其他系统和学科。这项研究采用了一种新的、新开发的方法，在高温/高压实验中定量控制非常少量的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）的融化形成岩浆，其中一些最终到达地球？年代的表面。因为氢会迅速扩散到地球上最常见的矿物质之一——橄榄石中？在地幔中，获得该奖项的研究人员现在能够将预定浓度的水注入直径约300微米的橄榄石球体中。然后，这些橄榄石被用作实验中的湿度计，以确定地幔岩石（即橄榄岩固体）开始熔化的确切时刻的压力依赖性。了解这种基本反应是很重要的，因为地幔（即橄榄岩）的融化推动了大洋中脊的扩散，并对地球的质量和热量的传递产生了重大影响。它的内部和表面以及地球的厚度？地壳。为了确定在H2O欠饱和条件下的橄榄石固溶体，将使用含有掺入特定H2O含量的San Carlos橄榄石球的合成橄榄岩，在1300℃左右和1至3 GPa范围内进行部分熔融实验。将球体作为湿度计，用二次离子质谱法分析橄榄石，以确定橄榄石的H2O含量何时发生变化，表明熔化的开始。研究目标是确定橄榄岩的固相以及Na2O和矿物模式对熔融的影响。结果将提供第一个定量测定水不饱和橄榄岩固体的实验。这项工作更广泛的影响包括方法开发和应用，从而为科学建立基础设施。它还提供研究生和本科生水平的学生培训。这种独特的矿物学湿度计也可以应用于材料科学和其他需要特定组成材料的固体的精确温度和压力的领域。