Doctoral Dissertation Research: Reconstructing the Paleoenvironmental History of the Cuenca Oriental in Mexico's Trans-Mexican Volcanic Belt

这个博士论文研究项目将研究气候变化与昆卡东部史前社会之间的可能联系，昆卡东部是跨墨西哥火山带东部的一个内陆流域。干旱被用来解释中美洲许多地区被遗弃的原因，但直接证据只适用于少数几个地点，而且经常提出非气候的解释。本博士论文研究项目将重点研究位于昆卡东部坎通纳（Cantona）考古遗址附近的两个马尔湖Aljojuca和Alchichica的人类活动和全新世气候变化的多代理记录。在古典时期晚期，坎通纳是美洲最大的城市之一，但几百年后，可能是由于干旱，这个地方被遗弃了。该博士生将通过分析aljojua和Alchichica沉积物岩心的化石花粉含量、稳定同位素组成和沉积物化学，建立全新世气候变化记录。将扫描花粉载玻片中的玉米花粉，作为该地区农业活动的指标。这些数据将有助于重建过去气候变化的时间以及该地区人类定居的历史。来自墨西哥国立自治大学和GFZ德国地球科学研究中心的一个国际科学小组已经恢复了Aljojuca核心。放射性碳测年法显示，地核跨度约为6200年。本论文项目将从东跨墨西哥火山带获得两个新的高分辨率、年代确定的古环境记录。这些记录将提高对该地区全新世气候变化时间的基本理解，特别是墨西哥夏季降雨制度的历史。因此，该项目将有助于考古学和地理学关于气候变化作为影响人类社会因素的作用的跨学科辩论。该项目将加强墨西哥、德国和美国科学家之间的国际合作。研究结果将通过各种媒体向学术界和公众传播，并将用于本科生和K-12学生的教育活动和课程计划。作为博士论文研究进步奖，该项目将提供支持，使有前途的学生建立一个独立的研究生涯。

This doctoral dissertation research project will examine possible linkages between climate change and prehistoric societies in the Cuenca Oriental, an area of interior drainage in the eastern Trans-Mexican Volcanic Belt. Drought has been invoked to explain the abandonment of many areas of Mesoamerica, but direct evidence is only available for a handful of sites, and non-climatic explanations often have been proposed. This doctoral dissertation research project will focus on development of a multi-proxy record of human occupation and Holocene climate change from Aljojuca and Alchichica, two maar lakes located near Cantona, an archaeological site in the northeastern part of the Cuenca Oriental. During the late Classic period, Cantona was one of the largest cities in the Americas, but the site was abandoned several hundred years later, possibly as a result of drought. The doctoral student will develop a record of Holocene climate change by analyzing the fossil pollen content, stable isotope composition, and sediment chemistry of sediment cores from Aljojuca and Alchichica. Pollen slides will be scanned for corn pollen as an index of agricultural activity in the area. These data will help reconstruct the timing of past changes in climate as well as the history of human settlement in the region. The Aljojuca core has already been recovered by an international scientific team from the National Autonomous University of Mexico and the GFZ German Research Center for Geosciences. Radiocarbon dating reveals that the core spans approximately 6,200 years.This dissertation project will produce two new high-resolution, well-dated paleoenvironmental records from the eastern Trans-Mexican Volcanic Belt. These records will improve basic understanding of the timing of Holocene climate change in the region, especially the history of Mexico's summer rainfall regime. The project therefore will contribute to interdisciplinary debates in archaeology and geography about the role of climate change as a factor influencing human societies. The project will strengthen international collaborations among scientists in Mexico, Germany, and the U.S. Results will be disseminated through a variety of media for scholarly and public audiences, and they will be used in educational activities and lesson plans for undergraduate and K-12 students. As a Doctoral Dissertation Research Improvement award, this project will provide support to enable a promising student to establish an independent research career.