Doctoral Dissertation Improvement Grant: Detection and Identification of Maize in Absorbed Pottery Residues: Development and Application

在Dr. Nikolaas van der Merwe的指导下，MS Eleanora Reber将为她的博士论文收集数据。她的研究目标是开发一种技术来确定玉米是否在特定的史前遗址被食用。玉米在墨西哥高地被驯化，并传播到北美和南美的大部分地区。今天，它在旧世界和新世界都被广泛种植，是第二大收获作物（仅次于甘蔗）。由于玉米的产量与劳动力的关系及其相对的可靠性，玉米为整个新大陆的复杂社会提供了生存基础。考古学家认为，正是玉米农业的发展奠定了美国西南部、中西部和东南部早期文化爆发的基础。然而，由于在大多数考古遗址中，植物遗骸保存得很差，玉米存在的证据往往是间接的，科学家们不得不依赖于人类骨骼中细微的化学特征。雷伯女士正在开发一种有可能识别烹饪锅上玉米残留物的技术。人种学证据表明，印第安人在陶瓷容器中煮玉米很长一段时间，因为粘土是多孔的，它有可能吸收食物残渣。MS Reber将利用气相色谱仪/质谱联用和气相色谱仪-燃烧-质谱联用来分析从陶瓷中提取的化学残留物，以寻找玉米信号。将鉴定特定的化合物，并确定每种化合物的碳同位素比率。在世界许多地区，玉米与其他植物相比具有独特的同位素特征，这将提供独特的线索。雷伯博士将首先进行对照实验，将一种传统的美洲土著玉米放在陶瓷器皿中煮熟。然后这些将被埋在土壤中不同的时间长度，以近似考古情况。残留物将被提取并分析。在这些结果的基础上，这个过程将被微调，然后应用于考古标本。最后，雷伯将把这项技术应用到一个具体的考古问题上。大约在美国中西部出现复杂社会的时候，陶器类型发生了变化，薄壁容器取代了厚壁容器。考古学家推测，这一变化与玉米的引入同时发生，而且薄壁容器在准备玉米炖菜时效率更高。通过分析厚壁和薄壁血管，MS Reber将评估这一假设。这项研究之所以重要，有几个原因。它将有助于发展一种技术，如果成功，这种技术将适用于世界许多地区的许多考古遗址。这项工作将有助于深入了解美国的史前史，并有助于培养一位有前途的年轻科学家。

Under the direction of Dr. Nikolaas van der Merwe, MS Eleanora Reber will collect data for her doctoral dissertation. The goal of her research is to develop a technique to determine whether maize was consumed at specific prehistoric sites. Maize was domesticated in highland Mexico and spread through large portions of both North and South America. Today it is widely planted in both the Old and New Worlds and is the second largest harvested crop (after sugar cane). Because of the yield in relation to labor and its relative dependability maize provided the subsistence base from which complex society arose throughout much of the New World. Archaeologists believe that it was the development of maize-based agriculture which underlies the early cultural explosions in the US Southwest, Midwest and Southeast. However because floral remains are poorly preserved in most archaeological sites, often evidence for maize is indirect and scientists have been forced to rely, for example, on subtle chemical signatures in human bone. MS Reber is developing a technique with the potential to identify maize residue on cooking pots. Ethnographic evidence suggests that Native Americans boiled corn for extended periods in ceramic vessels and because clay is porous it has the potential to absorb food residue. MS Reber will utilize both a gas chromatograph/mass spectrometer and gas chromatograph-combustion-mass spectrometry to analyze chemical residue extracted from ceramics to search for a maize signal. Specific chemical compounds will be identified and the carbon isotope ratios of each determined. In many areas of the world maize has a distinctive isotopic signature in relation to other plants and it is this which shall provide the distinctive clue.MS Reber will first conduct controlled experiments in which a traditional variety of Native American maize is cooked in ceramic vessels. These will then be buried in soil for varying lengths of time to approximate archaeological situations. Residues will then be extracted and analyzed. On the basis of these results, the process will be fine-tuned and then applied to archaeological specimens. Finally MS Reber will apply the technique to a specific archaeological question. At approximately the time that complex society arose in the American Midwest, a shift in pottery types took place and thin walled vessels replaced their thick walled counterparts. Archaeologists have postulated that this change coincides with the introduction of maize and that thin walled vessels were more efficient for preparing corn stews. Through analysis of both thick and thin walled vessels, MS Reber will evaluate this hypothesis.This research is important for several reasons. It will help to develop a technique which, if successful, will be applicable in many archaeological sites in many regions of the world. The work will provide insight into the prehistory of the United States and will assist in training a promising young scientist.