Luminescence dating of Late Pleistocene/Early Holocene archaeological sites in Brazil

关于人类何时第一次殖民新大陆的问题，自19世纪以来，考古学家一直在争论。 直到最近，这一争论一直集中在北美的证据上，因为假定的切入点是通过北美，而被广泛接受的最早的石器传统克洛维斯仅限于北美。 在智利南部的蒙特维德遗址，人们越来越多地接受克洛维斯时代之前的年代，这使人们把注意力集中在南美洲的证据上。 南美洲的记录总体上表明，早期的技术和适应与克洛维斯截然不同，不太可能是它的后代，这是一个令人信服的论据，至少与克洛维斯同时代，如果不是更早的话，南美洲的占领，但这方面的证据比北美的证据要少得多。 特别有问题的是这些早期证据的年代。在美国国家科学基金会的资助下，华盛顿大学的詹姆斯·费瑟斯博士将在未来两年里开展一项针对巴西中部更新世晚期/全新世早期遗址的发光测年计划。 这项工作的大部分是与圣保罗大学的考古学家和体质人类学家合作进行的，他们一直在对里约热内卢北部米纳斯吉拉斯的拉戈阿圣地区的早期遗址进行系统研究。 这是一个喀斯特地区，以石灰石岩石掩体而闻名，其中包含100多具人类骨骼，据信可以追溯到这个早期时期。 就像著名的来自华盛顿州的肯尼威克人一样，这些骨骼在解剖学上与现代美洲土著人不同，可能表明早期从南亚迁移到新大陆。发光测年法建立在固态物理学基础上，能够测定沉积物最后一次暴露于光的时间，通常是沉积时。 通过发光测定单个颗粒年代的能力使该方法能够识别和潜在地测定混合或扰动沉积物的年代。 地层完整性在早期遗址常常是一个问题。 这项工作将为来自华盛顿大学和圣保罗大学的学生提供培训。关于人类如何以及何时到达新大陆，有许多相互竞争的论点。 这项研究的长期目标是提供一些来自南美洲的确凿证据，以评估这些不同的论点。 这项工作的结果将在国际期刊上发表，并向大众媒体传播。

The question about when humans first colonized the New World has been debated by archaeologists since the 19th century. Until very recently, the argument has centered on North American evidence, since the presumed entry point is through North America and the earliest lithic tradition that is widely accepted, Clovis, is confined to North America. The growing acceptance of pre-Clovis dates for the Monte Verde site in southern Chile has focused attention on the South American evidence. The South American record as a whole suggests an early technology and adaptation quite distinct from Clovis and not likely descendent from it. This is a compelling argument for occupation in South America at least contemporary with if not earlier than Clovis, but documentation of this evidence is much poorer than that for North America. Particularly problematic is the dating of this early evidence. With funding support from the National Science Foundation, Dr. James Feathers of the University of Washington will over the next two years be conducting a luminescence dating program targeting late Pleistocene/early Holocene sites in central Brazil. Much of this work is in collaboration with archaeologists and physical anthropologists from the University of Sao Paulo, who have been conducting a systematic study of early sites in the Lagoa Santa region of Minas Gerais, north of Rio de Janeiro. This is a karstic region renowned for limestone rockshelters containing more than 100 human skeletons believed to date to this early period. Like the famous Kenewick Man from Washington state, these skeletons differ anatomically from modern native Americans and may indicate an early migration to the New World from south Asia. Luminescence dating is founded in solid state physics and is able to date sediments to their last exposure to light, usually when they were deposited. The ability to date single grains by luminescence allows the method to identify and potentially date mixed or disturbed sediments. Stratigraphic integrity is often a problem at early sites. The work will provide training for students from both the University of Washington and the University of Sao Paulo. There are many competing arguments for how and when people first arrived in the New World. The long term goal of this research is to provide some solid evidence from South America to allow evaluations of these various arguments. Results from this work will be published in international journals and disseminated to the popular press as well.