Dating the 'Taung Child' Australopithecus africanus type specimen through U-Pb measurements of associated calcite crystals

通过相关方解石晶体的 U-Pb 测量测定“Taung Child”南方古猿非洲型标本的年代

• 批准号: NE/H011102/1
• 负责人: Randall Parrish
• 金额: $ 3万
• 依托单位: British Geological Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH011102%2F1
• 关键词: Dating; Taung; Child; Australopithecus; africanus

The 'Taung Child' was found in 1924 at the Buxton limestone quarry, Northwestern Province, South Africa. The 'Taung Child' was the first early hominid found in Africa and became the type specimen of Australopithecus africanus. Mining activities continued at the quarry and the geological context of the specimen was lost, hampering attempts to date the hominid and understand its ecological context. Because of this, current estimates for the age of the 'Taung Child' range from 3 million to 1 million years old. Such chronological uncertainty greatly hampers our understanding of early hominid evolution in Africa. We propose to take samples of calcite crystals attached to the endocast of the 'Taung Child' and other associated fossils for uranium-lead dating using state-of-the-art facilities at the NERC Isotope Geosciences Laboratory. Pilot evidence demonstrates the suitability of such calcite crystals for high-precision age determination, and permission to sample the calcites has been granted by the Hominid Access Committee. The proposed radiometric dates for the 'Taung Child' are likely to alter the current age-range for Australopithicus africanus, perhaps changing our understanding of ancestor-decendant relationships among early hominin species. The methods undertaken in this study can be applied to other early hominin specimens from the 'Cradle of Humankind' World Heritage Site, South Africa, thereby improving the chronology of human evolution in Africa, and the methods will be refined to maximize the scientific information obtained from the minimum use of valuable fossil material, thereby improving generic methods of analysis of rare and invaluable museum collections.

“陶孩子”于1924年在南非西北省的巴克斯顿石灰石采石场被发现。“Taung Child”是在非洲发现的第一个早期人科动物，并成为非洲南方古猿的模式标本。采石场的采矿活动仍在继续，标本的地质背景已经丢失，这阻碍了对原始人的年代测定和对其生态环境的了解。正因为如此，目前对“陶孩子”年龄的估计在300万到100万年之间。这种时间上的不确定性极大地阻碍了我们对非洲早期人类进化的理解。我们建议使用NERC同位素地球科学实验室最先进的设备，对“陶子”和其他相关化石的骨架上的方解石晶体进行取样，以进行铀铅定年。试点证据表明，这种方解石晶体适合于高精度的年龄测定，并且允许方解石取样已获得原始人准入委员会的批准。提出的“Taung Child”的辐射测定日期可能会改变目前非洲南方古猿的年龄范围，也许会改变我们对早期人类物种之间祖先-后代关系的理解。本研究中采用的方法可以应用于南非“人类摇篮”世界遗产地的其他早期古人类标本，从而改善非洲人类进化的年代学，并将对方法进行改进，以最大限度地利用有价值的化石材料获得科学信息，从而改进分析稀有和无价博物馆藏品的一般方法。