Wasser im ozeanischem Mantel am schnell spreizenden ostpazifischen Rücken; Infrarot-Spektroskopie an nominell wasserfreiem Orthopyroxen

快速扩张的东太平洋海脊上洋幔中的水；

基本信息

批准号：
202602759
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：
2011
资助国家：
德国
起止时间：
2010-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/202602759?language=en
关键词：
Wasser im ozeanischem Mantel am

项目摘要

Water that is present in the Earth's mantle in nominally anhydrous minerals (NAM's) has a significant influence on mantle dynamics. Orthopyroxene is a very important container for water. It may incorporate several hundred wt.-ppm H2O in the uppermost mantle and even higher amounts in deeper parts, because its storage capacity is pressure-enhanced. Any previous studies on water in mantle orthopyroxene were restricted to peridotite xenoliths from the sub-continental mantle. The first samples from the sub-oceanic mantle were recently studied in the course of an own, DFG-financed project. These first data reveal contrasting water contents in peridotite from the slow spreading Mid-Atlantic Ridge, from levels equal to water saturation in orthopyroxene at ODP-Leg 153 to contents that consistently are one order of magnitude lower at ODP-Leg 209. This contrast implies different mantle residence times after melt depletion and/or different uplift/exhumation rates. This preliminary investigation not only provides us with a better knowledge of the water contents in the mantle but also puts constraints concerning dynamic processes below spreading centers. To develop a more general model and to test the preliminary hypotheses, it is absolutely necessary to study peridotite from a fastspreading ridge. The project suggested is aimed at closing a fundamental gap of knowledge by investigating peridotitic orthopyroxene (water, major, minor and trace element contents, equilibrium conditions) from the Hess Deep, ODP-Leg 147.

名义上无水矿物（NAM）中地球地幔中存在的水对地幔动力学有重大影响。邻苯二烯是一个非常重要的水容器。它可能在最上层的地幔中包含数百wt.-PPM H2O，甚至更深的部分中的储存能力是压力增强的。任何先前关于地幔邻苯二甲烯中水的研究仅限于次大陆地幔的橄榄岩异种石。最近在DFG资助的项目过程中研究了次洋披风的第一批样品。这些第一个数据揭示了橄榄岩在橄榄岩中的水含量的对比，从大西洋中部山脊散布缓慢，从等于ODP-LEG 153的牙也等于水的饱和度到含有ODP-LEG 209的数量级的含量。这种对比意味着在融合式销售量消耗后的不同地面居住时间，这意味着在融合式降低和/或或/或/或/或/或或相差较差后，这项初步研究不仅为我们提供了对地幔中水内容的更好了解，而且还对动态过程的限制在扩展中心下方。为了开发一个更通用的模型并测试初步假设，绝对有必要从快速开发的山脊中研究橄榄岩。该项目旨在通过研究hess深，ODP-LEG 147的橄榄岩（水，主要，次要和痕量元素，水，次要和痕量元素的内容）来缩小知识的基本差距。