RUI: Polybaric Partial Melting of Peridotite

RUI：橄榄岩的多压部分熔融

• 批准号: 0510366
• 负责人: Brandon Schwab
• 金额: $ 19.45万
• 依托单位: Humboldt State University Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0510366&HistoricalAwards=false
• 关键词: RUI; Polybaric; Partial; Melting; Peridotite

The formation of basalt by partial melting of the Earth's mantle is one of the most significant geodynamic processes on the planet. Despite decades of high-pressure experiments, few peridotite partial melting data in the 2.0-3.0 GPa pressure range exist. In order to enhance our knowledge of near-solidus mantle melting, a three-year study investigating the 2.0-3.0 GPa partial melting systematics of multiple peridotite compositions will be completed. Handpicked olivine, orthopyroxene, clinopyroxene, and spinel grains from two mantle xenoliths, of differing compositional fertility, will be mixed in varying proportions to create starting materials of varying bulk composition. These same starting materials were studied previously at 1.0 GPa. Experiments will be performed using the piston-cylinder apparatus utilizing a combination of the diamond aggregate and "micro-sandwich" techniques to eliminate the problem of quench modification of the glass. This will enable determination of low melt fraction glass and residual crystalline phase compositions, estimation of solidus temperatures over a range of pressures, and quantification of melt productivity and the stoichiometry of mantle melting reactions. The resulting polybaric dataset will provide constraints on the processes resulting in the formation of basalts in the mid-ocean ridge environment, as well as other tectonic regimes where polybaric melting and peridotite-melt interaction occur. An integral component and broader impact of the project includes the direct involvement of undergraduate research students and completion of an experimental petrology laboratory at a primarily undergraduate institution. Teaching activities using the laboratory and project data will be developed and incorporated into the geology curriculum, thus benefiting a larger population of students long into the future.

地幔部分熔融形成玄武岩是地球上最重要的地球动力学过程之一。 尽管几十年的高压实验，在2.0-3.0 GPa压力范围内的橄榄岩部分熔融的数据很少存在。 为了提高我们对近固相线地幔熔融的认识，将完成一项为期三年的研究，调查2.0-3.0 GPa多种橄榄岩成分的部分熔融系统学。 手工挑选橄榄石，斜方辉石，单斜辉石，尖晶石颗粒从两个地幔捕虏体，不同的组成生育力，将混合在不同的比例，以创建不同的散装组成的起始材料。 先前在1.0 GPa下研究了这些相同的起始材料。 实验将使用活塞缸装置，利用金刚石骨料和“微夹层”技术的组合，以消除淬火改性的玻璃的问题。 这将使得能够确定低熔体分数玻璃和残余晶相组成，估计在一定压力范围内的固相线温度，以及量化熔体生产率和地幔熔融反应的化学计量。由此产生的多压数据集将提供限制的过程中形成的玄武岩在洋中脊环境，以及其他构造制度，多压熔融和橄榄岩熔体相互作用发生。 该项目的一个组成部分和更广泛的影响包括本科研究生的直接参与，并在一个主要的本科机构完成实验岩石学实验室。 将开发利用实验室和项目数据的教学活动，并将其纳入地质学课程，从而使更多的学生在未来长期受益。