Plasma Oxidation Laboratory: Construction of a Multi-Sample Instrument

在国家科学基金会的支持下，舒拉考古研究与教育中心的凯伦·斯蒂尔曼博士将建造一台多样品等离子氧化仪，用于处理古代岩石艺术涂料样品，用于放射性碳测年。氧气辉光放电将岩画样品中的有机物质转化为二氧化碳，可以使用加速器质谱仪进行放射性碳测年。等离子体氧化已被用于矿物颜料绘画中的有机粘合剂的放射性碳测定，以及许多木炭颜料绘画中。近年来，岩石艺术研究人员越来越多地要求使用血浆提取技术进行测年研究。能够将岩石艺术放在按年代排列的背景下，可以将图像与从特定考古时期出土的文化遗迹一起研究。这种将岩石艺术研究与其他考古学专业(如石器、陶瓷和编织技术)结合在一起，对于开发一种研究过去文化的协同方法至关重要。在年代测定方法被开发出来之前，只有一些不同流派的岩石艺术的相对年龄和大致年龄范围是可能的。由于没有办法及时放置这些图像，考古学家大多忽视了这些对过去人类文化的洞察。通过该项目将化学和考古学结合起来，将直接满足国家对跨学科研究的需求。NSF对等离子体氧化实验室的支持促进了世界各地考古学家之间的合作。此外，我们还将把对考古科学感兴趣的大学生培养成实习生。需要更多对将化学知识应用于考古和文化应用感兴趣的科学家。考古科学的公众宣传将通过舒拉的博客、流行杂志/网站、舒拉学者STEM计划和公共宣传活动来完成。斯蒂尔曼博士设计了一套10室系统，能够同时氧化10个油漆样品，以便批量处理。这将增加样品吞吐量，减少分析时间，并降低岩石艺术测年的成本。通过建立一个多样品等离子氧化实验室，批量处理油漆样品将使舒拉能够扩大对其他考古项目的研究。USGS煤炭(不含C14)和ANU蔗糖(现代)放射性碳标准将用于测试结果的准确性和精密度。在存在草酸钙涂层的地点，草酸盐测年来自沉积的日期与来自绘画的等离子体氧化日期一致，这表明结果是有效的。这一裁决反映了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。

With support from the National Science Foundation, Dr. Karen Steelman of Shumla Archaeological Research & Education Center will construct a multi-sample plasma oxidation instrument used to process ancient rock art paint samples for radiocarbon dating. An oxygen glow discharge converts organic material in rock paintings samples to carbon dioxide, which can be radiocarbon dated using accelerator mass spectrometry. Plasma oxidation has been used to radiocarbon date organic binders in mineral-pigmented paintings, as well as many charcoal-pigmented paintings. In recent years, there has been an increased demand by rock art researchers to use the plasma extraction technique for dating studies. The ability to place rock art in a chronological context allows an inventory of images to be studied together with excavated cultural remains from a given archaeological time period. This incorporation of rock art studies alongside other archaeological specialties, such as lithics, ceramics, and weaving techniques, is crucial for developing a synergistic approach to studying past cultures. Before dating methods were developed, only relative ages and approximate age ranges for some distinct genres of rock art were possible. Without a way to place the images in time, archaeologists had mostly ignored these insights into past human cultures. The integration of chemistry and archaeology through this project will directly address a national need for interdisciplinary research. NSF support for the plasma oxidation laboratory fosters collaborations among archaeologists worldwide. In addition, we will train university students interested in archaeological science as interns. More scientists with interests in applying chemical knowledge to archaeological and cultural applications are needed. Public outreach for archaeological science will be accomplished via Shumla's blog, popular magazines/websites, the Shumla Scholars STEM program, and public outreach events. Dr. Steelman has designed a 10 chamber system that has the ability to oxidize 10 paint samples in tandem for batch processing. This will increase sample throughput, decrease analysis time, and reduce costs for rock art dating. By constructing a multi-sample plasma oxidation laboratory, batch processing of paint samples will allow Shumla to expand research for additional archaeological projects. USGS coal (C14-free) and ANU sucrose (modern) radiocarbon standards will be used to test the accuracy and precision of results. At sites where calcium oxalate coatings are present, both oxalate dates from accretions and plasma oxidation dates from paintings agree, suggesting valid results.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.