Archaeological Chronology Development and the Old Wood Problem on the Northern Colorado Plateau

在美国国家科学基金会（National Science Foundation）的支持下，罗纳德·h·托纳博士（Ronald H. Towner）及其同事和学生将对科罗拉多州西部和犹他州东部考古遗址的放射性碳定年法中存在的“老木头”问题进行研究。古老的木材问题是，从木材木炭中测定的放射性碳（14C）往往比发现木炭的环境要古老得多。五个因素可以使柴火的年代明显早于其考古或现代背景：1)人们倾向于使用枯木作为燃料；2)枯树或枯枝可能早在其木材被用作燃料之前就死了；3)树木死后的风化、腐烂或昆虫活动会使许多外年轮脱落，并增加残腐木的使用日期与使用时间之间的差距；4)通过燃烧去除额外的外环可以进一步扩大间隙；而从木材环系列的内部进行年轮测定，则进一步扩大了这一差距。单独或一起操作，这些过程可能产生日期和木材使用之间的差距，超出放射性碳测年的不确定范围，从而严重高估所涉及遗址的年龄。这个拟议的项目使用放射性碳和树木年轮测年来检查“老木材”采购对史前和历史时期科罗拉多州西部和犹他州东部的影响。先前的研究表明，旧木材问题的严重程度在空间、环境和文化上各不相同。通过沿着环境梯度在三个地区收集大量样本，该项目将评估不同环境对薪材资源的年龄和可用性的影响。当地多物种多世纪树木年轮年表的构建对于确定科罗拉多州西部和犹他州东部的弗里蒙特、盖特韦传统和尤特遗址的年代尤为重要，对于理解弗里蒙特/尤特关系和尤特人种发生也至关重要。这个提议的项目将帮助我们开发三个群体的木材使用模型，并为遗址的年代确定提供解释性指导。因此，该项目的智力价值在于测试放射性碳测年的环境变异性，为该地区创建新的树木年轮年表，开发文化木材使用实践的新模型，并评估技术变化作为这些地区遗址放射性碳测年的一个因素。该项目将产生更广泛的影响，超出弗里蒙特，盖特传统和尤特考古学在科罗拉多州西部和犹他州东部。它将为了解全球干旱和半干旱环境下的放射性碳定年和木材利用实践做出重要贡献。该项目也将有助于研究生和本科生的培训和发展。它也可能有助于校准其他计时器技术，如考古磁和热释光测年，并完善史前弗里蒙特和原始历史和早期历史尤特陶器类型的陶瓷系列化研究。它将改进可能对了解技术变革对木材资源开发的影响产生影响的木材使用模式。

With the support of the National Science Foundation, Dr. Ronald H. Towner, colleagues and students will examine the 'old wood' problem in radiocarbon dating of archaeological sites in western Colorado and eastern Utah. The old wood problem is the tendency for radiocarbon (14C) determinations from wood charcoal to be significantly older than the contexts in which the charcoal is found. Five factors can make firewood dates significantly earlier than their archaeological or modern contexts: 1) the tendency of people to use dead wood for fuel; 2) a dead tree or dead branch may have died long before its wood was used for fuel; 3) weathering, decay, or insect activity after tree death can remove many exterior rings and increase the gap between the date of the deadwood remnant and the time of its use; 4) removal of additional exterior rings by burning can further expand the gap; and 5) dating rings from the inner part of the wood's ring series widens the gap still further. Operating singly or together, these processes can produce a gap between date and wood use that exceeds the uncertainty range of radiocarbon dates and thereby seriously overestimate the age of the site involved. This proposed project uses both radiocarbon and tree-ring dating to examine the impacts of 'old wood' procurement on interpretations of the prehistoric and historical period occupations of western Colorado and eastern Utah. Previous research indicates that the magnitude of the old wood problem varies spatially, environmentally, and perhaps culturally. By collecting abundant samples in three areas along an environmental gradient, the project will assess the impacts of different environments on the age and availability of fuelwood resources. The construction of local multi-species multi-century tree-ring chronologies will be particularly important for dating of Fremont, Gateway Tradition, and Ute sites in western Colorado and eastern Utah, and may be critical in understanding Fremont/Ute relationships and Ute ethnogenesis. This proposed project will help us develop wood use models for the three groups and provide interpretive guidelines for dating the sites. Thus, the intellectual merit of the project is to test environmental variability of radiocarbon dates, create new tree-ring chronologies for the area, develop new models of cultural wood use practices, and evaluate technological change as a factor in radiocarbon dating of sites in these areas.This project will have broader impacts beyond the Fremont, Gateway Tradition, and Ute archaeology in western Colorado and Eastern Utah. It will make important contributions toward the understanding of radiocarbon dating and wood use practices in arid and semi-arid environments worldwide. The project will also contribute toward graduate and undergraduate student training and development. It may also contribute to calibration other chronometric techniques, such as archaeomagnetism and thermoluminescence dating, and to refining ceramic seriation studies of prehistoric Fremont and protohistoric and early historic Ute pottery types. It will refine models of wood use that may have implications for understanding the impacts of technological change on the exploitation of timber resources.