Doctoral Dissertation Improvement Grant: Stable Isotopic Evidence for Landscape Reconstructions, Kapthurin Formation, Kenya

在 Sally McBrearty 博士的指导下，David Leslie 将分析化石土壤有机碳、土壤碳酸盐和动物牙釉质，以获得可用于环境重建的稳定同位素值。 这些化石指标是在 2011 年和 2012 年野外季节在肯尼亚巴林戈湖盆地收集的，那里的地质构造卡普图林地层保存了可追溯到 545 - 235 千年前中更新世时期的沉积物。 卡普图林地层保存了从阿舍利时代到中石器时代过渡的考古证据，这一时期标志着重大的技术变革，并以我们自己的物种——智人的出现而达到顶峰。 莱斯利先生的研究重点是重建这一时期的环境，同时开发一种新技术，利用计算机遥感和地理信息系统，将现代环境的生物量生产力与现代土壤有机碳和碳酸盐的稳定同位素指标联系起来。 这项技术为重建过去的环境提供了一种新的环境代理，并且广泛适用于其他时期以及考古和古生物遗址。人们普遍认为，环境的变化会影响物种多样性和物种形成。 在东非中更新世期间，发生了重大的生物和技术变化，并且可能是由环境变化驱动的。 该项目将重建两个独立的景观，可追溯到 545 - 509 年前和 509 - 235 000 年前，可供阿舍利和中石器时代的人类祖先使用，以辨别景观、环境、资源和技术使用方面的差异或相似之处。 稳定同位素值将从 720 个现代和化石土壤有机碳、碳酸盐和动物牙釉质样本中得出，以重建这些环境。 最终，这项研究旨在测试东非中更新世期间环境变化对技术和生物变化的影响，以及与巴林戈湖盆地相关的大陆气候变化模型的准确性。 这项研究将强调在重建环境时使用多种证据以获得过去环境的最佳近似值的重要性。 初步研究是在 2011 年和 2012 年夏天在肯尼亚同事的帮助下进行的，部分得到了美国国家科学基金会 (BCS 0917965) 向 McBrearty 博士的资助以及康涅狄格大学向 McBrearty 博士和 Leslie 先生的资助的部分支持。 这项研究的结果将通过会议演讲、讲座和同行评审出版物与同事分享。 该项目创建的原始数据将通过在线数据存储库提供，从而向公众开放。 未来，莱斯利先生计划将开发的遥感、地理和信息系统方法以及稳定同位素提取和分析技术纳入本科生的实践实验室课程中。

Under the guidance of Dr. Sally McBrearty, David Leslie will analyze fossil soil organic carbon, soil carbonates, and animal tooth enamel for stable isotopic values useful for environmental reconstructions. These fossil indicators were collected during the field seasons of 2011 and 2012 in the Lake Baringo basin, Kenya, where a geologic formation, the Kapthurin Formation, preserves sediments that date to 545 - 235 thousand years ago, during the Middle Pleistocene. The Kapthurin Formation preserves archaeological evidence for the transition from the Acheulian to the Middle Stone Age, a time period that marks significant technological change and culminates with the emergence of our own species, Homo sapiens. Mr. Leslie's research will focus on reconstructing environments during this time period, while also developing a novel technique to link the biomass productivity of modern environments with stable isotopic indicators from modern soil organic carbon and carbonates using computerized remote sensing and geography information systems. This technique offers a new environmental proxy to use when reconstructing past environments, and is broadly applicable to other time periods and archaeological and paleontological sites.It is widely accepted that changes in environments can affect species diversity and speciation. During the Middle Pleistocene of East Africa, significant biological and technological change occurred and could be driven by changing environments. This project will reconstruct two separate landscapes, dating to 545 - 509 and 509 - 235 thousand years ago, available to Acheulian and Middle Stone Age human ancestors, to discern any differences or similarities in the use of landscapes, environments, resources, and technology. Stable isotope values will be derived from 720 samples of modern and fossil soil organic carbon, carbonates, and animal tooth enamel to reconstruct these environments. Ultimately this research seeks to test the effect of environmental change on technological and biological changes during the Middle Pleistocene of East Africa and the accuracy of continental models of climate change in relation to the Lake Baringo basin. This research will highlight the importance of using multiple lines of evidence when reconstructing environments to arrive at the best approximation of past environments. Preliminary research was conducted with the help of Kenyan colleagues during the summers of 2011 and 2012, and was supported in part by grants to Dr. McBrearty from the National Science Foundation (BCS 0917965) and grants to Dr. McBrearty and Mr. Leslie from the University of Connecticut. The results of this research will be shared with colleagues through conference presentations, lectures, and peer-reviewed publications. The raw data created from this project will be made available via an online data repository, thereby making it accessible to the public. In the future, Mr. Leslie plans to incorporate remote sensing and geography and information systems methods developed, as well as stable isotope extraction and analysis techniques, into hands-on laboratory classes for undergraduates.