(142) 有证据表明,在岩根中存在丰富的岩水库
Dewashish Upadhyay1, Erik E Scherer, Klaus Mezger
1Zentrallabor für Geochronologie, Institut für Mineralogie, Universität Münster, Corrensstrasse 24, 48149 Münster, Germany. upadhyay@uni-muenster.de
Nature
|June 26, 2009
概括
早期的地球地球.
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
- 早期地球的差异化分化.
背景情况:
- 萨马-146 (Sm-146) 到-142 (Nd-142) 同位素系统追踪了早期的地球分化事件.
- 岩石中Nd-142/Nd-144比率的变化表明太阳系形成后4亿年内发生的过程.
- 之前的发现表明,基于高的Nd-142/Nd-144值,早期的不兼容元素枯竭的地幔.
研究的目的:
- 为了研究地球岩层地幔中古代水库的同位素特征.
- 为了确定早期形成的丰富地幔水库的证据.
- 了解早期地球差异化特征的长期保存.
主要方法:
- 对Nd-142/Nd-144同位素组成的分析.
- 性岩石的放射测年.
- 地幔水库的地化学建模.
主要成果:
- 低的Nd-142/Nd-144值被测量在来自印度的148亿年前的性岩石中.
- 这些低值表明,至少在42亿年前形成的,富含不兼容元素的古老水库存在.
- 这种丰富的特征在石质层地幔根中持续到至少148亿年前.
结论:
- 地球的地幔包含长寿的丰富储备,除了耗尽的储备外.
- 这些丰富的水库,年龄可能是哈迪时代,可能逃脱了与对流地幔的混合.
- 古代克拉顿的石层根可以保存早期地球差异化的同位素特征.
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