Enhancing shared facilities for archaeological science at the University of Arizona

该合同将为购买扫描微x射线荧光光谱仪（micro - xrf）提供资金，用于树木化学和其他研究。这项研究意义重大，因为它使科学家能够重建过去环境的多个方面以及随着时间的推移环境的变化。许多种类的树木每年都会长出明显的年轮。年轮的宽度可能每年都有很大的变化，这些变化的模式可能足够独特，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。树木年代学最早于20世纪30年代在亚利桑那大学发展起来。一旦定年，这些环可以用来重建控制环宽度的因素的变化。这些因素包括年降雨量、年气温（高海拔地区）、森林火灾的频率以及树木生长的地区。树木化学是一门相对较新的科学——研究树木各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木年轮研究实验室（LTRR）的大量现代和古代木材核心进行新颖的树木化学研究。该仪器还将成为LTRR与来访的高中科学班进行外联工作的宝贵工具。该仪器将安装在LTRR。一项重点工作将是寻找以前火山爆发和主要森林火灾的年轮的证据，这两种情况都会导致某些化学元素的峰值，然后被生长的树木吸收。由于火山爆发通常会将火山灰（微火山灰）扩散到一个非常大的区域，因此它们提供了一种潜在的有价值的方法，可以将一个大区域内的考古和古环境序列联系起来。通过显微xrf进行的树木化学分析可能提供了一种快速有效的方法来检测和确定这些过去的火山喷发的年代。LTRR中估计有30-40,000个木材样本目前无法确定切割日期，因为外圈模糊不清。然而，初步研究表明，在一些物种的心材/边材连接处，以及倒数第二环，有明显的化学变化。Micro-XRF将用于扫描当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.