Center for American Paleolithic Research, 27930 Cascade Road, Hot Springs, South Dakota, USA.
Department of Paleontology, San Diego Natural History Museum, San Diego, California, USA.
Nature. 2017 Apr 26;544(7651):479-483. doi: 10.1038/nature22065.
The earliest dispersal of humans into North America is a contentious subject, and proposed early sites are required to meet the following criteria for acceptance: (1) archaeological evidence is found in a clearly defined and undisturbed geologic context; (2) age is determined by reliable radiometric dating; (3) multiple lines of evidence from interdisciplinary studies provide consistent results; and (4) unquestionable artefacts are found in primary context. Here we describe the Cerutti Mastodon (CM) site, an archaeological site from the early late Pleistocene epoch, where in situ hammerstones and stone anvils occur in spatio-temporal association with fragmentary remains of a single mastodon (Mammut americanum). The CM site contains spiral-fractured bone and molar fragments, indicating that breakage occured while fresh. Several of these fragments also preserve evidence of percussion. The occurrence and distribution of bone, molar and stone refits suggest that breakage occurred at the site of burial. Five large cobbles (hammerstones and anvils) in the CM bone bed display use-wear and impact marks, and are hydraulically anomalous relative to the low-energy context of the enclosing sandy silt stratum. Th/U radiometric analysis of multiple bone specimens using diffusion-adsorption-decay dating models indicates a burial date of 130.7 ± 9.4 thousand years ago. These findings confirm the presence of an unidentified species of Homo at the CM site during the last interglacial period (MIS 5e; early late Pleistocene), indicating that humans with manual dexterity and the experiential knowledge to use hammerstones and anvils processed mastodon limb bones for marrow extraction and/or raw material for tool production. Systematic proboscidean bone reduction, evident at the CM site, fits within a broader pattern of Palaeolithic bone percussion technology in Africa, Eurasia and North America. The CM site is, to our knowledge, the oldest in situ, well-documented archaeological site in North America and, as such, substantially revises the timing of arrival of Homo into the Americas.
人类最早向北美扩散是一个有争议的话题，建议早期的遗址必须满足以下标准才能被接受：（1）考古证据是在明确界定且未受干扰的地质背景下发现的；（2）年龄是由可靠的放射性测年确定的；（3）来自跨学科研究的多条证据提供一致的结果；（4）在原始环境中发现无可置疑的文物。在这里，我们描述了 Cerutti Mastodon（CM）遗址，这是一个来自更新世晚期的考古遗址，在那里原地锤和石砧与单个乳齿象（Mammut americanum）的零碎遗骸时空相关。CM 遗址包含螺旋破裂的骨头和臼齿碎片，表明在新鲜状态下发生了断裂。这些碎片中的几个还保留了打击的证据。骨骼、臼齿和石头的重新组装的发生和分布表明，断裂发生在埋葬地点。CM 骨床中的五块大石（锤和砧）显示出使用痕迹和撞击痕迹，并且相对于封闭的砂质淤泥层的低能量环境，它们具有水力异常。使用扩散-吸附-衰变测年模型对多个骨骼标本进行 Th/U 放射性分析表明，埋葬日期为 130.7±9.4 千年前。这些发现证实了在最后一个间冰期（MIS 5e；更新世晚期）期间，CM 遗址存在未被识别的人类物种，这表明具有手部灵巧性和使用锤和砧的经验知识的人类处理乳齿象四肢骨骼以提取骨髓和/或制作工具的原始材料。CM 遗址明显存在系统的象骨减少，这与非洲、欧亚大陆和北美的旧石器时代骨敲击技术的更广泛模式相符。CM 遗址是我们所知的北美最古老的原地、有充分记录的考古遗址，因此大大修改了人类到达美洲的时间。
