Spatial and temporal variations in mantle redox state beneath the Massif Central, France

法国中部地块的第三纪和第四纪火山作用在大范围的地理区域内以橄榄岩包体的形式采集了大陆下岩石圈地幔(SCLM)的样品。Lenoir等人的地球化学研究。(2000)和Downes et al.(2003)提出存在两个不同的地幔区域，分别位于北纬45°30‘和南纬45°30’。这里的目标是追踪地幔氧化还原状态的变化，这将提供关于欧洲这一地区SCLM演化的进一步线索，例如，如果这两个区域记录了不同的氧化还原状态。除了空间变化外，还可以通过分析不同喷发年龄(~20 Ma至最近)的火山中心的捕虏体来研究时间变化。交代作用的影响也将被监测，因为这种相互作用经常被观察到以改变氧化还原状态。这项研究将提供有关西欧下SCLM化学演化的重要新信息。

The Tertiary and Quaternary volcanism of the Massif Central, France, has sampled the subcontinental lithospheric mantle (SCLM) in the form of peridotite xenoliths over a large geographical area. Geochemical studies by Lenoir et al. (2000) and Downes et al. (2003) suggest the existence of two distinct mantle domains, lying north and south of 45° 30’ latitude, respectively. The goal here is to trace the variations in mantle redox state that will provide further clues about the evolution of the SCLM in this part of Europe, for example if these two domains record distinctive redox states. In addition to spatial variations, temporal changes can be studied by analysing xenoliths from volcanic centers with different eruption ages (~20 Ma to recent). The effects of metasomatism will also be monitored since such interactions are often observed to modify redox state. This study will provide important new information on the chemical evolution of the SCLM beneath Western Europe.