早期的小行星融化从45.662 Gyr的年龄开始,用于差异化石
Joel Baker1, Martin Bizzarro, Nadine Wittig
1School of Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand. joel.baker@vuw.ac.nz
Nature
|August 27, 2005
概括
石中的放射性同位素有助于确定太阳系形成的日期. 岩石的年代为456.62亿年前,证实了短暂的同位素引发了行星的早期融化.
科学领域:
- 宇宙化学 宇宙化学
- 行星科学 行星科学
- 地质时间学 (Geochronology)
背景情况:
- 石中的放射性同位素作为太阳系形成模型的计时器.
- 分化石起源于化的母体,但它们的矿物质年龄往往比分化时间线更年轻.
- 较年轻的年龄表明热源如短寿命核化物 ((26) Al, (60) Fe) 在化之前衰变,挑战现有模型.
研究的目的:
- 研究小行星融化的时间及其热源.
- 通过使用石石测年法来精确太阳系的最小年龄.
- 测试短寿命放射性核酸在太阳系早期热事件中的作用.
主要方法:
- - (Pb-Pb) 基岩石的年代. 基岩石的年代.
- 在批量愤怒石样本中测量-26 ((26) Mg) 过剩.
主要成果:
- 玄武岩石的年代为4.5662 ± 0.0001亿年,仅比太阳系最小年龄年轻100万年.
- 证实 (26) Al 衰变通过观察到的 (26) Mg 过量导致酸盐母体的融化.
- 修订后的太阳系最小年龄为4.5695 ± 0.0002亿年.
结论:
- 差异化行星体的积累可能先于不差异化的行星体.
- 短暂的核化物,特别是 (26) Al 和 (60) Fe,在注射后不久就能够触发行星微小的融化.
- 这项研究完善了我们对早期太阳系的热历史和年龄的理解.
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