相关实验视频
Updated: Jul 12, 2026

08:14
Atom Probe Tomography Analysis of Exsolved Mineral Phases
Published on: October 25, 2019
概括
海洋岛屿玄武岩显示出明显的同位素成分,可能来自下层地幔. 这一发现挑战了地幔羽毛在上升过程中主要引入上层地幔的想法.
科学领域:
- 地质化学 地质化学
- 同位素地球化学 同位素地球化学
- 地幔石化学地幔石化学
背景情况:
- 海洋岛基岩 (OIB) 在地化学研究中经常显示线性同位素阵列.
- 枯竭的上层地幔通常被认为是地幔羽毛的主要来源或混合端.
- 以前的模型表明,地幔羽毛在从670公里边界层上升时引入了大量上层地幔物质.
研究的目的:
- 调查OIB的同位素组成,并确定它们的源成分.
- 为了测试地幔羽毛起源于670公里边界层并入上层地幔的假设.
- 描述OIB中潜在的新同位素成分.
主要方法:
- 在海洋岛屿基岩中分析 (Sr), (Nd) 和 (Pb) 的同位素比例.
- 同位素混合阵列的地球化学建模.
- 观察到的同位素组成与地幔羽毛模型预测的比较.
主要成果:
- 观察到的OIB同位素数组是风扇形的,而不是简单的线性数组.
- 枯竭的上层地幔很少是这些OIB阵列中的终端成员.
- 阵列汇聚在具有低87Sr/86Sr和高143Nd/144Nd,206Pb/204Pb和3He/4He比率的同位素组成部分上.
结论:
- 风扇形的阵列表明,一个独特的,非放射性同位素成分参与了OIB石化.
- 这个组成部分与下层地幔源相一致,可能起源于核心-地幔边界层.
- 在上升过程中,地幔羽毛可能会从下层地幔,而不是仅仅是上层地幔,吸入物质.
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