Doctoral Dissertation Research Improvement Grant: Environmental Reconstruction of Mesoamerica's Northern Frontier through Stable Isotope Analysis of Leporid Bones

在玛格丽特·舍宁格博士的指导下，安德鲁·萨默维尔将重建美国和墨西哥四个北美考古遗址横断面过去的环境条件。这将通过对兔子和野兔（leporid）骨骼（n = 347）应用稳定同位素分析来实现。选定的考古遗址地理位置横跨墨西哥中部和美国西南部之间的干旱地区，时间范围涵盖公元 200 年至 1200 年。哺乳动物骨骼中碳氮和氧的同位素比率受到当地植物组成、平均降水量和相对湿度等环境因素的影响，因此对古代标本的分析可以重建过去的景观。除了考古样本外，萨默维尔先生还将分析从博物馆收藏中挑选的大量现代豹纹动物骨骼，以提供基线数据来帮助解释前西班牙豹纹动物的同位素值。来自每个考古地点的环境数据将允许调查长期环境与社会之间的动态关系。该项目重点关注中美洲核心北部的边缘干旱景观，因为该地区社会政治复杂性的兴衰文化历史模型经常将气候变化视为驱动因素。公元六世纪，复杂的中美洲社会扩展到墨西哥中部北部的沙漠地区，特别是现代的萨卡特卡斯州和杜兰戈州。尽管被占领了四个世纪，干旱北部最复杂的政体，如拉克马达和阿尔塔维斯塔，在公元 900 年左右就被废弃了。这些广泛的发展和衰落模式导致学者们认为，有利的环境条件允许中美洲文明的扩张，而严重和长期的干旱导致其最终萎缩。该项目产生的同位素数据要么将为中美洲扩张和收缩的环境因素的显着作用提供第一个实证支持，要么将提供与这一长期假设相反的证据。更一般地说，本论文研究将增进我们对全新世晚期复杂社会发展和衰落过程中环境作用的理解。重建选定地点最初几年的环境条件将解决有关生态因素与早期社会经济发展之间关系的模型，特别是农业生产区为新兴发展经济体提供强大优势的概念。了解导致每个地点政治崩溃或废弃的环境条件将为研究快速社会转型时期存在的社会环境模式提供机会，并确定导致系统脆弱性或弹性的社会策略。最终，本论文从过去的社会环境相互作用中寻求模式、趋势和教训，以更好地体现我们现代环境问题的背景。

Under the guidance of Dr. Margaret Schoeninger, Andrew Somerville will reconstruct past environmental conditions across a transect of four North American archaeological sites in the United States and Mexico. This will be accomplished through the application of stable isotope analysis to rabbit and hare (leporid) bones (n=347). The selected archaeological site locations geographically span the arid regions between Central Mexico and the Southwest United States, and temporally cover the period of AD 200-1200. Isotopic ratios of carbon nitrogen and oxygen in mammalian bone are influenced by environmental factors such as local botanical composition, average precipitation, and relative humidity, and thus analysis of ancient specimens enables the reconstruction of past landscapes. In addition to archaeological samples, Mr. Somerville will analyze a large collection of modern leporid bones selected from museum collections in order to provide baseline data to aid in the interpretation of isotopic values of pre-Hispanic leporids. Environmental data from each archaeological location will permit investigations of the dynamic relationship between environment and society over long stretches of time. This project focuses on marginal arid landscape of north of the Meosoamerican core as cultural historical models for the rise and decline of socio-political complexity in the region have frequently implicated climatic change as a driving factor. During the 6th century AD, complex Mesoamerican societies expanded into the desert regions north of Central Mexico, particularly the modern states of Zacatecas and Durango. Despite four centuries of occupation, most complex polities of the arid north, such as La Quemada and Alta Vista, were abandoned at about AD 900. These broad patterns of development and decline led scholars to argue that favorable environmental conditions permitted the expansion of Mesoamerican civilization and that severe and prolonged droughts brought about its eventual retraction. Isotopic data generated from this project will either provide the first empirical support for prominent role of environmental factors of the expansion and contraction of Mesoamerica, or will provide evidence contrary this long-standing assumption. More generally, this dissertation research will increase our understanding of the role of the environment during the development and decline of complex societies during the Late Holocene. Reconstructing the environmental conditions present during the initial years of selected sites will address models concerning the relationship between ecological factors and incipient socioeconomic development, particularly the notion that agriculturally productive zones provided powerful advantages to newly developing economies. Knowing the environmental conditions leading up to political collapse or abandonment at each site will provide opportunities to study social-environmental patterns present during periods of rapid social transformation and to identify social strategies which led to systemic vulnerability or resiliency. Ultimately, this dissertation seeks patterns, trends, and lessons from past social-environmental interactions that may better contextualize our modern environmental concerns.