Middle Pleistocene Human Behavioral Adaptations in the Kapthurin Formation, Kenya

在国家科学基金会的支持下，Sally McBrearty博士和一个合作者团队将在肯尼亚进行三个季节的实地考察，以研究石材技术和古代环境的变化。 该项目的重点是Kapthurin组，这是一个年代久远的中更新世序列，富含石器、骨骼化石、植物化石和其他古生境指标。 我们的物种智人的起源发生在卡普图林组所跨越的时间间隔期间的非洲，早期智人的出现与被称为阿舍利到中石器时代过渡的考古学变化相吻合。以手斧为特征的阿舍利技术消失了，取而代之的是中石器时代的手工艺品，如尖和其他小薄片工具。这种转变反映了一种深刻的行为重组，这可能是智人认知能力增强的产物。 或者，技术本身可能在构建独特的人类适应性生态位方面发挥了作用，导致了人类化石记录中的解剖学变化。因此，事件发生的时间和环境条件，对于理解导致我们物种起源的过程至关重要。该项目的目的是确定技术和景观使用方面的变化，检测随着时间的推移发生的任何变化，并为这些发展建立时间框架。这项研究将对比卡普图林地层中的两个时间间隔，第一个可以追溯到55万至509,000年前，第二个可以追溯到509,000至235,000年前。在较早的时间间隔中的先前工作提供了一个基线，可以将在较早的时间间隔中的当前工作的结果与该基线进行比较。在两个地点在较年轻的时间间隔内进行的测量将提供关于人工制品和化石骨骼的密度和特征的信息。地质测绘将提供关于古代地形和环境的重要资料，这些资料将通过地理信息系统加以综合。通过研究植物化石、花粉、草壳、植硅体和哺乳动物牙齿化石的稳定同位素含量，将记录古代植被。在其中一个挖掘地点的各种动物的化石足迹将被保存和铸造，足迹鉴定将提供对该地点被占领时存在的动物群落的独特见解。将寻求特定工具类型和生境特征之间的相关性，以评估技术变异性的环境解释。 将发现的模式与较旧的时间间隔进行比较，以评估随时间变化的性质和程度。这项研究将提供有关导致智人起源的过程的本质的重要新信息，这是当今人类进化研究中争论的一个关键问题。 该项目是与肯尼亚国家博物馆合作开展的。 它将有助于培训美国和肯尼亚的学生，并加强博物馆的收藏和基础设施。 美国、欧洲和肯尼亚学者将参与数据收集、分析和结果传播。

With support from the National Science Foundation, Dr. Sally McBrearty and a team of collaborators will conduct three seasons of field work in Kenya to examine changes in stone technology and ancient environment. The project focuses upon the Kapthurin Formation, a well dated Middle Pleistocene sequence that is rich in stone artifacts, fossil bone, fossil plants, and other paleohabitat indicators. The origin of our species, Homo sapiens, occurred in Africa during the time interval spanned by the Kapthurin Formation, and the appearance of early Homo sapiens coincides with the archaeological change known as the Acheulian to Middle Stone Age transition. Acheulian technology, characterized by handaxes, disappeared, and was replaced by Middle Stone Age artifacts such as points and other small flake tools. This shift reflects a profound behavioral reorganization that may be the product of the increased cognitive ability of Homo sapiens. Alternatively, the technology itself may have played a role in the construction of the unique human adaptive niche, leading to the anatomical changes seen in the human fossil record. Thus the timing of events, and the environmental circumstances under which they occurred, are critical to understanding the processes leading to the origin of our species. The aims of the project are to identify variations in technology and use of the landscape, to detect any changes through time, and to establish the temporal framework for these developments. The research will contrast two time intervals in the Kapthurin Formation, the first dating to 550,000 - 509,000 years ago, the second to 509,000 - 235,000 years ago. Previous work in the older time interval provides a baseline to which results from the current work in the younger interval can be compared. Excavations at two sites in the younger time interval will provide information on the density and characteristics of artifacts and fossil bones. Geologic mapping will furnish important information on the ancient topography and environment which will be integrated using a Geographic Information System (GIS). The ancient vegetation will be documented by the study plant fossils, pollen, grass cuticles, phytoliths, and the stable isotope content of mammalian fossil teeth. Fossil footprints of a variety of animals at one of the excavated sites will be conserved and cast, and footprint identification will provide unique insight into the faunal community present at the time the site was occupied. Correlation of specific tool types and habitat features will be sought to assess environmental explanations technological variability. Patterns discovered will be compared to those of the older time interval to assess the nature and degree of change through time. This research will provide critical new information about the nature of the processes leading to the origin of Homo sapiens, a key issue of debate in human evolutionary study today. The project is conducted in collaboration with the National Museums of Kenya. It will contribute to the training of both American and Kenyan students and the enhancement of museum collections and infrastructure. American, European, and Kenyan scholars will participate in data collection, analysis, and dissemination of results.