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齿釉质，以寻找对环境重建有用的稳定同位素值。这些化石指示物是在2011年和2012年在肯尼亚巴林戈湖盆地的野外季节收集的，那里的地质构造Kapthurin组保存了可以追溯到545-23.5万年前的沉积物，也就是中更新世。卡普图林组保存了从阿舍利时代向石器时代中期过渡的考古证据，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。Leslie先生的研究将侧重于在这段时间内重建环境，同时开发一种新技术，利用计算机化的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替代物，并广泛适用于其他时期和考古古生物遗址。人们普遍认为，环境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，并可能受到环境变化的推动。这个项目将重建两个独立的景观，可以追溯到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，以辨别在景观、环境、资源和技术使用方面的任何不同或相似之处。将从720个现代和化石土壤有机碳、碳酸盐和动物牙釉的样本中提取稳定的同位素值，以重建这些环境。最终，这项研究试图测试环境变化对东非中更新世期间技术和生物变化的影响，以及与巴林戈湖盆地有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条证据线以得出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，部分资金来自国家科学基金会(BCS 0917965)对麦克布雷蒂博士的资助，以及康涅狄格大学对麦克布雷蒂博士和莱斯利先生的资助。这项研究的结果将通过会议报告、讲座和同行评议的出版物与同事分享。从该项目创建的原始数据将通过一个在线数据储存库提供，从而向公众开放。未来，莱斯利计划将开发的遥感、地理和信息系统方法，以及稳定的同位素提取和分析技术，纳入本科生的动手实验室课程。

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.