Enhancing shared facilities for archaeological science at the University of Arizona

该合同将用于购买用于树枝化学和其他研究的扫描微型X射线荧光(Micro-XRF)光谱仪。这项研究意义重大，因为它允许科学家重建过去环境的多个方面以及随着时间的推移环境变化。许多树种每年都会增加一个明显不同的年轮。年轮的宽度每年可能会有很大的不同，这些变化模式可能足够独特，可以通过与该地区的主年表进行比较来确定给定地点的木材的年代。树的年代学最早是在30年代的S在亚利桑那大学发展起来的。一旦确定了年轮的年代，就可以用来重建控制年轮宽度的因素的变异。这些数据包括年降雨量、年气温(高海拔地区)、森林火灾的频率，以及树木生长的地区。一门相对较新的科学是树枝化学--研究树内不同年轮之间化学成分的变化。该奖项将允许亚利桑那大学的研究人员对亚利桑那大学树轮研究实验室(LTRR)从现代和古代木材中提取的大量岩芯进行新颖的树枝化学研究。该仪器也将是LTRR与访问高中科学课堂的外展工作的宝贵工具。仪器将安装在LTRR。当务之急是在过时的年轮中寻找以前火山喷发和重大森林火灾的证据，这两种火灾都会导致某些化学元素的峰值，然后被不断生长的树木吸收。由于火山喷发经常将火山灰(微火山灰)散布在非常大的区域内，它们提供了一种潜在的有价值的手段，可以在大范围内将考古和古环境序列联系起来。用微型XRF进行树枝化学分析可能提供一种快速而有效的手段来检测和测定这些过去的喷发的日期。LTRR估计有30-40,000个木材样本目前无法指定切割日期，因为外环模糊不清。然而，初步研究表明，在几个物种的心材/边材连接处以及倒数第二个年轮中，都发生了独特的化学变化。Micro-XRF将被用来扫描目前未确定日期的岩心，以寻找这些信号，从中可以得出切割日期。这项研究可能会为考古和古环境解释提供更多的年代样本。

This award will fund the purchase of a scanning micro X-Ray Fluorescence (Micro-XRF) spectrometer for dendrochemical and other research. The research it enables is significant because it permits scientists to reconstruct multiple aspects of past environments and environmental change over time. Many species of trees add a visibly distinct ring of wood each year. The width of the annual ring may vary substantially from year to year, and these patterns of variation may be sufficiently distinctive to allow wood from a given site to be dated by comparison to a master chronology for the region. Dendrochronology was first developed at the University of Arizona in the 1930's. Once dated, the rings may be used to reconstruct variation in the factors controlling ring width. These include annual rainfall, annual temperature (at high altitude), the frequency of forest fires, and in which region the tree grew. A relatively new science is dendrochemistry - the study of variation in chemical composition from ring to ring within a tree. This award will allow researchers at the University of Arizona to undertake novel dendrochemical research on the enormous archive of cores from modern and ancient wood in the University of Arizona's Laboratory of Tree Ring Research (LTRR). The instrument will also be a valuable tool for LTRR'S outreach work with visiting high school science classes.The instrument will be installed in LTRR. A priority will be the search for evidence in dated tree rings of former volcanic eruptions and major forest fires, both of which result in spikes of certain chemical elements that are then taken up by growing trees. Since volcanic eruptions often spread ash (microtephra) over a very large area, they offer a potentially valuable means of correlating archaeological and paleoenvironmental sequences across a large region. Dendrochemical analysis by micro-XRF potentially offers a quick and efficient means of detecting and dating these past eruptions. An estimated 30-40,000 wood samples in LTRR cannot currently be assigned a cutting date because the outer ring is indistinct. Pilot research has however shown distinctive chemical changes at the heartwood/sapwood junction in several species, and also in the penultimate ring. Micro-XRF will be used to scan currently undated cores to look for these signals, from which cutting dates can be derived. This research can potentially make available many more dated samples for archaeological and paleoenvironmental interpretation.