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·萨默维尔将在美国和墨西哥的四个北美考古遗址的横断面上重建过去的环境条件。这将通过对兔骨和兔骨(n=347)进行稳定同位素分析来实现。选定的考古地点地理上横跨墨西哥中部和美国西南部之间的干旱地区，时间上覆盖公元200-1200年。哺乳动物骨骼中碳、氮和氧的同位素比率受到当地植物成分、平均降雨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，萨默维尔还将分析从博物馆收藏品中挑选出来的大量现代勒波利人骨骼，以便提供基准数据，帮助解释西班牙裔前勒波利特人的同位素价值。来自每个考古地点的环境数据将使人们能够在很长一段时间内调查环境和社会之间的动态关系。该项目的重点是中美洲核心区北部的边缘干旱地貌，因为该地区社会政治复杂性的兴衰的文化历史模型常常暗示气候变化是一个驱动因素。在公元6世纪，复杂的中美洲社会扩展到墨西哥中部以北的沙漠地区，特别是现代的萨卡特卡斯州和杜兰戈州。尽管占领了四个世纪，但干旱北部的大多数复杂政体，如拉奎马达和阿尔塔维斯塔，在公元900年左右被抛弃。这些广泛的发展和衰落模式导致学者们争辩说，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了最终的撤退。该项目产生的同位素数据将首次为环境因素在中美洲扩张和收缩中的重要作用提供经验支持，或者将提供与这一长期假设相反的证据。更广泛地说，本论文的研究将加深我们对环境在全新世晚期复杂社会发展和衰落中的作用的理解。重建选定地点最初几年的环境条件将涉及生态因素与初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经济体提供强大优势的概念。了解每个地点导致政治崩溃或被遗弃的环境条件，将提供机会研究快速社会转型期间出现的社会环境模式，并查明导致系统脆弱性或复原力的社会战略。最终，这篇论文从过去的社会-环境互动中寻找模式、趋势和教训，以更好地为我们的现代环境关切提供背景。

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.