Doctoral Dissertation Improvement Award: Phytolith Analysis in Determination of Environmental Change

该项目研究了中旧石器时代晚期(LMP~60-40 ka)和旧石器晚期早期(EUP~46-30 ka)人类石器技术和行为的转变与环境的关系。这种转变与智人的领土扩张和尼安德特人的逐渐消失有关。这一过渡的时机和性质因地理区域而异。它为什么以及如何发生仍然是旧石器时代晚期考古学的主要问题之一。在这项研究中，调查了横跨LMP-EUP的三个地理和环境截然不同的地点的微观植物遗骸。将环境与尼安德特人和现代人的技术和地理运动进行比较，可以看出当地景观的变化对行为变化的影响程度。这里使用的方法适用于旧石器时代晚期的考古学，为研究人员提供了一个研究同样问题的直接工具。在上一个冰河时代，该地区充当了植物的气候避难所，可能也是尼安德特人和现代人的避难所。今天，该地区是一个生物多样性的热点地区，有6000多种植物。因此，了解气候变化导致的过去当地环境变化不仅对于了解早期原始人的行为，而且对于了解环境对未来气候变化的反应都是重要的。考古学特别适合研究气候对当地环境的影响，因为研究的时间较长。该项目使用植硅体分析来重建过去的环境。植硅体是植物细胞的二氧化硅印记，因此是当时植物存在的直接证据。将植硅石用于环境娱乐已是家喻户晓，几乎可以在任何有或曾经有植物的地方使用。以前，区域现代土壤样本从不同的环境中提取，并进行分析以创建植被指纹，将植硅体组合与特定的植被类型联系起来。这项工作的结果提供了一个代理，显示了在特定环境中可以预期的植物硅体类型。通过对考古植硅体组合的统计分析，结合现代数据，对过去的环境进行了详细的再现。这些结果与该地区不同研究小组在过去20年中获得的人类行为考古数据一起进行了分析。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project investigates the relationship between environment and the shift in hominin stone tool technology and behavior occurring during the Late Middle Paleolithic LMP ~60–40 ka) and Early Upper Paleolithic (EUP ~46—30 ka). This shift is associated with the territorial expansion of Homo sapiens and the gradual disappearance of Homo neanderthalensis. The timing and nature of this transition differs across geographic regions. Why and how it occurred remains one of the major questions in late Paleolithic archaeology. In this study, microscopic plant remains from three geographically and environmentally distinct sites spanning the LMP—EUP are investigated. Comparing the environment to the technology and geographical movement of Neanderthals and modern humans sheds light on the degree to which changes in the local landscape influenced changes in behavior. The methods utilized here are applicable to late Paleolithic archaeology providing researchers a straightforward tool to investigate the same questions. During the last ice age, the region acted as a climatic refuge for plants, and possibly also Neanderthals and modern humans. Today, the region is a biodiversity hotspot with over 6000 species of plants. Understanding past local environment change as a result of climate change can therefore be important to understand not only behavior of earlier hominins, but also how the environment responds to future climate change. Archaeology is particularly well placed to study the influence of climate on local environments owing to the extended periods of time studied. This project uses phytolith analysis to recreate past environments. Phytoliths are silica imprints of plant cells, and therefore direct evidence of the plants present at the time. The use of phytoliths for environmental recreation is well established and can be applied in virtually any place where there are or have been plants. Previously, regional modern soil samples were taken from different environments, and analyzed to create vegetation fingerprints, associating phytolith assemblages with particular vegetation types. The result of this work provides a proxy, showing what type of phytoliths can be expected in a particular environment. Through statistical analysis of the archaeological phytolith assemblages in conjunction with the modern data, a detailed recreation of past environments are produced. These results are analyzed alongside archaeological data of hominin behavior acquired over the last two decades by different research groups in the region.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.