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40Ar/39Ar 来自海地的白-第三纪边界特克提石的年龄
概括
来自海地和蒙大拿州的德基石和桑尼丁的阿贡-阿贡测年证实白-第三纪 (K-T) 边界撞击事件发生在64.5亿年前,使地质和撞击时间线保持一致.
科学领域:
- 地质时间学 (Geochronology)
- 古生物学的古生物学
- 冲击石坑的形成
背景情况:
- 甲-第三纪 (K-T) 边界标志着一个重要的大规模灭绝事件.
- 确定K-T边界和相关冲击事件的精确时间对于理解灭绝动态至关重要.
研究的目的:
- 通过放射测年技术精确地确定K-T边界和奇克苏鲁布撞击事件的日期.
- 为了确定K-T边界,沉积岩层和撞击事件之间的时间相关性.
主要方法:
- 阿贡-阿贡 ((40) Ar/ ((39) Ar) 地质年代学被用来测定海地海洋沉积岩中发现的德基石的日期.
- 来自蒙大拿州大陆沉积岩中K-T边界以上的顿岩层的桑尼丁也使用 (40) Ar / (39) Ar分析进行了日期测定.
主要成果:
- 来自海地的特克石给出了精确的 (40) Ar/(39) Ar 年龄,即64.5 +/- 0.1百万年前.
- 来自蒙大拿州本托尼特层的桑尼丁提供了64.6 +/- 0.2百万年前的不可区分的年龄.
- 这些结果确定了K-T边界和撞击事件的同期性质.
结论:
- K-T边界撞击事件的确切日期为大约6450万年前.
- 这项研究证实了撞击事件与K-T大灭绝事件的同步性.
- 精确的地质年代数据解决了关于这个关键地质和生物转变的时间的长期问题.
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