Construction of a low-level 14C facility at the University of Arizona

在国家科学基金会的支持下，亚利桑那大学的J.Quade博士、A.Jull博士和N.Lifton博士将建造一个新的、最先进的实验室设施，可以对非常古老的样品进行碳14测年，超过大约45,000年。对于考古学家和地质学家来说，碳14测年是一项基本的测年技术，它在40,000年前的样品中的使用相对简单。在更老的样品中，留下来用于测年的原始碳-14如此之少，以至于样品很容易被空气和自然水中较年轻的碳-14污染，从而使样品看起来比实际年龄年轻得多。亚利桑那州拟建的设施将专门用于处理这些旧样本，方法是去除微量的污染，并在提取过程中将样本与大气彻底隔离。如果一切按计划进行，将有可能可靠地测定出以前无法测定年代的40-6万年的考古资料。考古学家将从这些新的分析能力中受益最大。仅举一个例子，考古学家之间存在着激烈的争论，关于欧洲尼安德特人和解剖学上的现代人在公元30至50年间共存的时间和地理范围。近几十年来，旧石器时代中期和晚期人口之间出现了一幅复杂的时间和地理重叠的图景。这一观点的基础主要是大量新遗址和重新挖掘遗址的放射性碳测年，主要是使用标准的木炭14C测年方法。这些遗址的年代测定表明，在西欧的部分地区，尼安德特人和解剖学上的现代人可能已经毗邻生活了数千年。我们的设施一旦建成，将处于独特的位置，可以检查这些和其他欧洲人的重建是按时间顺序合理的，还是仅仅是污染的人工制品。亚利桑那大学人类学系最近收到了NSF的IGERT(综合研究生教育和研究培训计划)拨款，旨在培训地质考古学和考古学学生在三个研究领域之一：计时学、古生态学和技术。至少有一名或两名IGERT奖学金学生将加入这个项目，并将新提取线的开发和应用作为其研究生研究的全部或部分内容。本文所述的拟议研究正是IGERT计划设想的在创新新方向上的研究生培训机会。当新的提取线建造时，将获得相关的考古样本并进行分析。

With National Science Foundation support, Drs. J. Quade, A. Jull and N. Lifton at the University of Arizona will build a new, state-of-the-art laboratory facility that will permit carbon-14 dating of very old samples, beyond about 45,000 years. Carbon-14 dating is an essential dating technique for archeologists and geologists alike, and its use in samples younger than 40,000 years old is relatively straightforward. In samples older than that, so little of the original carbon-14 is left for dating that samples are easily contaminated by younger carbon-14 in the air and from natural waters, thus making samples appear much younger than they are. The proposed facility at Arizona will be specifically constructed to deal with these old samples by removing minute quantities of contamination, and by thoroughly isolating samples from the atmosphere during the extraction process. If all goes as planned, it will be possible to reliably date previously undatable archeological material in the 40-60,000 years range.Archeologists stand to benefit the most from these new analytical capabilities. As just one example, there is a highly contentious debate among archaeologists over the timing and geographic extent of the coexistence between Neanderthals and anatomically modern human populations in Europe during the period ~30 to 50 14C kyr B.P. In recent decades a complex picture has emerged of the temporal and geographic overlap between Middle and Upper Paleolithic populations. The basis for this view is largely radiocarbon dating of a large number of new and re-excavated sites, mostly using the standard 14C dating method on charcoal. What is suggested from the dating of these sites is that Neanderthal and anatomically modern human populations may have lived adjacent to each other for thousands of years in parts of western Europe. Our facility, once constructed, will be uniquely positioned to examine whether these and other reconstructions of the peopling of Europe are chronologically sound or merely artifacts of contamination.The Department of Anthropology at the University of Arizona recently received an IGERT (Integrative Graduate Education and Research Traineeship Program) grant from NSF intended to train geoarchaeology and archaeology students in one of three research areas: chronometry, paleoecology, and technology. At least one and perhaps two IGERT fellowship students will join this project and make the development and applications of the new extraction lines either all or part of their graduate research. The proposed research described herein is exactly the kind of graduate student training opportunity in innovative new directions envisioned by the IGERT program.When the new extraction lines are constructed relevant archaeological samples will be obtained and analyzed..