IPG: Collaborative Research: A high-resolution analysis of unique paleoenvironmental data from key hominin sites in East Africa

IPG：合作研究：对东非主要古人类遗址的独特古环境数据进行高分辨率分析

• 批准号: 1241025
• 负责人: James Russell
• 金额: $ 7.14万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-10-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1241025&HistoricalAwards=false
• 关键词: IPG; Collaborative; Research; resolution; analysis

The possibility that human evolution in Africa has been strongly influenced by Earth's climatic and environmental history over the last several million years has been an important question at the forefront of paleoanthropological research. One fundamental question is: can any of the potential envionmental drivers of evolutionary change be reconstructed with enough precision to allow us to relate them with confidence to the episodes of speciation, extinction and cultural evolution known to anthropologists, and thereby test their relationships in time and space?This team of paleoanthropologists and earth scientists plans to analyze climate and other environmental histories to provide direct tests of key hypotheses linking environmental history and mammal (including early human) evolution by collecting and analyzing detailed paleoenvironmental data at three key anthropological sites in Africa. They will collect continuous paleoenvironmental records by drilling long sediment cores from ancient lake beds in the northern Afar, Ethiopia (~3.8-2.9 million years ago-Ma), the Baringo Basin, Kenya (~3.2-2.35 Ma), and the Turkana Basin, Kenya (~2.3-1.42 Ma), and relate these records to the outcrops in the same basins that contain early human and other mammal fossils, as well as stone tools in the younger time periods. As a group these basins contain some of the most critical evidence for human evolutionary history in Africa. Although past investigators have reconstructed climate and other environmental histories from the outcrops in which the fossil humans and artifacts have been found, such environmental records are highly discontinuous due to the nature of the sediments where the fossils occur, and are unsuitable for many of the most informative geochemical records available today because of the weathering that has affected outcropping sediments. Drilling lakebeds near the fossil sites gets around these problems, because lake sediments accumulate much more continuously, and because drilling into the subsurface allows unweathered samples to be collected Funding for the drilling costs for this project has been secured from other sources: with the IPG funds the team will analyze the cores to generate quantitative and high resolution records of changes in temperature, precipitation, vegetation, fire and volcanic activity and other factors which may have influenced human evolution.The primary research goal is to obtain long cores from these basins, each of which span critical intervals in human evolution and are close to hominin fossil and archaeological sites. The researchers will apply state-of-the-art paleoenvironmental and paleoclimate methods to these cores to assemble high resolution records covering much of the past four million years of East African environmental history. The team will then evaluate existing hypotheses and generate new hypotheses linking climate history to early human physical and cultural evolutionary adaptations. The paleoenvironmental and paleoecological data collected from the drill cores will be linked directly in time and space to the nearby fossil human, mammal and stone tool records by way of the numerous volcanic ashes present in both the cores and outcrops, along with other dating techniques. By comparing the new records to similar records from nearby ocean sediment cores the researchers plan be able to distinguish local from global drivers of environmental change and in the process test a series of hypotheses linking key events in human evolution with climate and other aspects of environmental history. Finally, the team will use these new, combined paleoenvironmental and paleoanthropological data sets, combined with novel modeling techniques to better understand how landscape and climate change across various scales of time and space may have affected the availability and predictability of critical ecosystem resources upon which early humans would have depended. This project will greatly expand our understanding of African climate history and will be an opportunity to invigorate interest in human evolution and its relationship to climate with the US and African public. The project will train many American and African students during its field, analytical and internship/synthesis phases, and will generate numerous informal science learning opportunities through our collaborations with the National Museums of Kenya and Ethiopia and the Smithsonian Institution.

在过去的几百万年里，非洲的人类进化受到地球气候和环境历史的强烈影响，这一可能性一直是古人类学研究的一个前沿重要问题。一个基本的问题是：任何潜在的环境驱动因素的进化变化是否可以足够精确地重建，使我们能够自信地将它们与人类学家已知的物种形成、灭绝和文化进化的事件联系起来，从而测试它们在时间和空间上的关系？这个由古人类学家和地球科学家组成的团队计划通过收集和分析非洲三个关键人类学遗址的详细古环境数据，分析气候和其他环境历史，为将环境历史和哺乳动物（包括早期人类）进化联系起来的关键假设提供直接检验。他们将在埃塞俄比亚阿法尔北部（~ 380 - 290万年前）、肯尼亚巴林戈盆地（~3.2-2.35 Ma）和肯尼亚图尔卡纳盆地（~2.3-1.42 Ma）的古湖床上钻取长沉积物岩心，收集连续的古环境记录，并将这些记录与同一盆地中含有早期人类和其他哺乳动物化石以及更年轻时期石器的裸露物进行比较。作为一个整体，这些盆地包含了非洲人类进化史的一些最重要的证据。尽管过去的研究人员已经从发现人类化石和人工制品的露头岩层中重建了气候和其他环境历史，但由于化石所在的沉积物的性质，这些环境记录是高度不连续的，并且由于风化作用影响了露头岩层的沉积物，因此这些环境记录不适合今天可用的许多最有信息的地球化学记录。在化石遗址附近的湖床上钻探可以解决这些问题，因为湖泊沉积物的积累更加持续，而且钻探到地下可以收集到未风化的样本，这个项目的钻探成本已经从其他来源获得了资金：在IPG的资助下，研究小组将分析这些岩芯，生成温度、降水、植被、火灾和火山活动以及其他可能影响人类进化的因素的定量和高分辨率的变化记录。主要的研究目标是从这些盆地中获得长岩心，每个盆地都跨越了人类进化的关键时期，并且接近古人类化石和考古遗址。研究人员将对这些岩心采用最先进的古环境和古气候方法，以收集覆盖东非过去400万年环境历史的高分辨率记录。然后，该团队将评估现有的假设，并提出将气候历史与早期人类身体和文化进化适应联系起来的新假设。从岩心中收集的古环境和古生态数据将通过岩心和露头中存在的大量火山灰，以及其他测年技术，在时间和空间上直接与附近的人类化石、哺乳动物化石和石器记录联系起来。通过将新记录与附近海洋沉积物岩心的类似记录进行比较，研究人员计划能够区分环境变化的局部和全球驱动因素，并在此过程中测试一系列将人类进化中的关键事件与气候和环境历史的其他方面联系起来的假设。最后，研究小组将利用这些新的、结合了古环境和古人类学的数据集，结合新的建模技术，更好地理解景观和气候变化是如何在不同的时间和空间尺度上影响早期人类赖以生存的关键生态系统资源的可用性和可预测性的。这个项目将极大地扩展我们对非洲气候历史的理解，并将是一个机会，激发美国和非洲公众对人类进化及其与气候关系的兴趣。该项目将在实地、分析和实习/综合阶段培训许多美国和非洲学生，并将通过我们与肯尼亚和埃塞俄比亚国家博物馆以及史密森学会的合作，提供许多非正式的科学学习机会。