Water contents in nominally anhydrous minerals in oceanic peridotite

大洋橄榄岩中名义无水矿物的含水量

• 批准号: 5442230
• 负责人: Professorin Dr. Esther Schmädicke
• 金额: --
• 依托单位: Lehrstuhl für Mineralogie
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2004
• 资助国家: 德国
• 起止时间: 2003-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5442230?language=en
• 关键词: Water; contents; nominally; anhydrous; minerals

Olivine, ortho- and clinopyroxene are the main constituents of the Earth`s upper mantle. Although these minerals are nominally anhydrous, they can host traces of water, predominantly as OH defects, with concentrations of hundreds to thousands ppm H2O. These amounts of hydrous components have a disproportionately large effect on the physical and chemical properties of minerals and rocks. They enhance deformation, increase ionic diffusion and electrical conductivity in the asthenosphere and also may influence the melting behaviour. So far, predominantly xenoliths were used in order to measure the water contents in mantle minerals. No data are available für the suboceanic mantle. However, the knowledge of water contents is very important für implications on mantle rheology, convection and plate tectonics. The focus of this project, therefore, is to determine the water concentrations in oceanic peridotite. The unique samples taken at the Mid-Atlantik ridge (ODP legs 153 and 209) shall be investigated in this context. These peridotites are well suited for this purpose: (¡) They preserve relics of olivine and pyroxenes of sufficient size for measurements. (¡¡) They reveal different fabrics, from undeformed to strongly sheared, which is very fortunate in order to assess to weakening effect of water on mineral deformation.

橄榄石，邻苯二氧化碳是地球上地幔的主要构成。尽管这些矿物质在名义上是无水的，但它们可以以OH缺陷为主要的水痕迹，浓度为数百至数千ppm H2O。这些量的含水成分对矿物质和岩石的物理和化学性质的影响不成比例。它们增强了变形，增加了微弱圈的离子扩散和电导率，也可能影响熔融行为。到目前为止，主要使用异种石，以测量地幔矿物质中的水含量。没有可用的数据für。但是，对水的知识是对地幔风湿病，建筑和板块构造的非常重要的含义。因此，该项目的重点是确定海洋橄榄岩的水浓度。在这种情况下，应研究在Atlantik Ridge中部（ODP腿153和209）中采集的独特样品。这些橄榄岩非常适合此目的：（;）它们保留了足够大小的橄榄石和辉石的遗物，以进行测量。 （;）它们揭示了不同的织物，从未呈现到强剪切的织物，这是非常幸运的，以评估水对矿物质变形的影响削弱。

项目成果

Deep solid-state equilibration and deep melting of plagioclase-free spinel peridotite from the slow-spreading Mid-Atlantic Ridge, ODP Leg 153

来自缓慢扩张的大西洋中脊的无斜长石尖晶石橄榄岩的深层固态平衡和深层熔融，ODP Leg 153

• DOI: 10.1007/s00710-010-0125-7
• 发表时间: 2010
• 期刊: Mineralogy and Petrology
• 影响因子: 1.8
• 作者: Will TM;Schmädicke E;Frimmel HE
• 通讯作者: Frimmel HE