Characterization of diverse origins for orthopyroxene in ultramafic rocks

超镁铁质岩石中斜方辉石不同来源的表征

• 批准号: 86894522
• 负责人: Dr. Tatjana Rehfeldt
• 金额: --
• 依托单位: GeoZentrum Nordbayern
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/86894522?language=en
• 关键词: Characterization; diverse; origins; orthopyroxene; ultramafic

Some upper mantle peridotites have recently been found to be strongly enriched in orthopyroxene due to interaction of silica-rich melt with surrounding mantle. Additionally, some eclogite xenoliths from Archaean Cratons have lost a silica-rich melt fraction. Recent findings on Kaapvaal Craton peridotite xenoliths point towards different orthopyroxene trace element compositions in peridotite which previously experienced high degree partial melting and orthopyroxene crystallization due to reaction with silica-rich metasomatic melts. This project will examine naturally occurring peridotitic orthopyroxene from different petrogenetic settings. Differences in the trace element composition of orthopyroxene with different petrogenetic histories (e.g. residues after melt depletion, reaction of peridotite with subduction-related melt or cumulate crystallization) will help understanding the process of silica enrichment of the upper mantle. Additionally, preliminary high pressure and high temperature experiments will be conducted analysing the behaviour of trace elements in orthopyroxene during partial melting and melt/rock interactions.

近年来，一些上地幔橄榄岩被发现强烈富集斜方辉石，这是由于富硅熔体与周围地幔相互作用的结果。此外，一些榴辉岩捕虏体从Escherichia purons已经失去了富硅熔体部分。最近的研究结果Kaapvaal的岩石橄榄岩捕虏体指向不同的斜方辉石微量元素组成的橄榄岩，以前经历了高度的部分熔融和斜方辉石结晶，由于与富硅交代熔体反应。本项目将研究不同成岩背景下天然存在的橄榄岩斜方辉石。具有不同成岩历史（熔体亏损后的残留物、橄榄岩与俯冲相关熔体反应或堆积结晶）的斜方辉石微量元素组成的差异有助于理解上地幔硅富集的过程。此外，将进行初步的高压和高温实验，分析部分熔融和熔体/岩石相互作用过程中斜方辉石中微量元素的行为。