已知最古老的东非智人
Céline M Vidal1,2, Christine S Lane3, Asfawossen Asrat4,5
1Department of Geography, University of Cambridge, Cambridge, UK. cv325@cam.ac.uk.
Nature
|January 13, 2022
概括
据火山灰的新测年显示,东非最古老的智人化石,特别是Omo I,
科学领域:
- 古人类学和地质年代学
- 在东非的早期人类进化
背景情况:
- 埃塞俄比亚主要的智人化石 (Omo-Kibish和Herto) 之前的年龄估计依赖于岩年代测定,分别为197年和160-155年左右.
- 这些年龄估计及其底层层和地形相关性面临科学挑战.
- 早期的智人化石的确切年代对于了解现代人类起源的时间表至关重要.
研究的目的:
- 重新评估和建立一个更准确的最低年龄的奥莫-基比什智人化石.
- 调查以往东非人类化石的测定年龄的研究中使用的测定年龄的相关性.
- 提供新的地质年代数据来支持或修改早期智人进化的时间表.
主要方法:
- 卡莫亚人种遗址 (KHS) 岩层的地化学分析,该岩层在层级上覆盖了Omo I化石.
- 将KHS岩与埃塞俄比亚主要裂中的沙拉火山的特定火山爆发事件联系起来.
- 来自沙拉火山爆发的近距离沉积物的放射测年 (40Ar/39Ar),以确定KHS岩的最低年龄.
主要成果:
- 位于Omo I的KHS岩与沙拉火山喷发有着地化学联系.
- 沙拉火山爆发沉积物的新年代为奥莫I化石提供了233 ± 22 千年的最低年龄.
- KHS 丝与 Waidedo Vitric 丝没有相关性,使其用于测定 Herto 人类的年龄无效.
结论:
- 已知最古老的东非智人化石 (Omo I) 现在至少可以追溯到233年,比以前所接受的要古老得多.
- 这一修订的年龄与独立的证据一致,
- 这项研究驳斥了之前的特弗拉相关性,需要对其他早期人类化石遗址的约会进行重新评估.
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