An Investigation of Early Hominin Land Use in and Around the Sterkfontein Valley Using Strontium Isotopes

在国家科学基金会的支持下，马特·斯彭海默博士和一个国际同事团队将对南非斯特尔方丹山谷及其周围的早期原始人景观使用情况进行研究。景观利用掌握着有关人类起源的重要线索。例如，有人提出，我们的祖先出现两足动物，是为了适应森林环境萎缩所需的长途旅行。然而，几乎没有直接证据表明早期原始人会走这么远的距离。为了验证这些假说，考古学、人类古生物学和生物地球化学专家团队将研究古人类化石和相关动物的锶同位素组成，以提供早期古人古景观利用的第一个直接证据。这是可能的，因为哺乳动物组织中的锶同位素比率直接反映了当地地质中的锶同位素组成，因此从一个地质基质到另一个地质基质的运动反映在动物组织中，如牙釉质。这项研究将分为两个阶段。首先，该团队将对现代斯特尔方丹山谷及其周边地区的现代水、土壤、植物和动物中的锶同位素组成进行全面研究，作为研究该山谷化石的基线。这一阶段还将包括一系列实验，旨在确定哪些类型的仪器将被证明是从化石中获得大量锶同位素分析最有利的。在第二阶段，将分析早期人和非人动物的牙釉质，试图回答关于早期人的家园范围、迁徙模式和社会行为的问题。这项研究的学术价值在于，它将使该团队和其他人能够开始解决一些以前难以解决的问题，例如早期人类祖先是否迁徙，与现代黑猩猩相比，两足动物的出现是否与活动范围的扩大有关，以及雄性或雌性是否从出生群体中分散出来，以及分散发生在什么年龄。因此，这项研究提供了极大地丰富我们对早期原始人生态学和生活史的理解的可能性，并通过这样做，应该更好地理解人类的起源。此外，这项研究将建立一个关于土壤、水、植物和动物中锶同位素在地质多样性景观中的分布的大型数据集，这将被证明对考古学家、古生物学家、生态学家、地球化学家和法医科学家感兴趣，他们对跟踪人类和其他生物的运动感兴趣。该项目的更广泛影响将包括促进美国、南非和英国科学家之间的广泛国际合作。这将包括主办一次小型国际讲习班，以传播这项研究的结果，并确定今后研究的领域。该项目还将对教育做出重大贡献，因为它将为美国和南非传统上代表性较低的群体的学生提供博士后和研究生培训。

With National Science Foundation support, Dr. Matt Sponheimer and an international team of colleagues will conduct a study of early hominin landscape use in and around the Sterkfontein Valley, South Africa. Landscape use holds important clues regarding human origins. For instance, it has been suggested that bipedalism arose in our forebears as an adaptation for traversing long distances necessitated by shrinking forest environments. Yet, there is little direct evidence that early hominins traveled such long distances. In order to test such hypotheses, the team of specialists in archaeology, human paleontology, and biogeochemistry will study the strontium isotope compositions of fossil hominins and associated fauna to provide the first direct evidence of early hominin paleolandscape utilization. This is possible because the strontium isotope ratios in mammalian tissues directly reflect the strontium isotope compositions of the local geology, and thus movement from one geological substrate to another is reflected in an animal's tissues such as tooth enamel.This study will consist of two phases. In the first, the team will perform a comprehensive study of strontium isotope compositions in the modern water, soils, plants, and animals of the modern Sterkfontein Valley and surrounding areas to serve as a baseline for the study of the Valley's fossils. This phase will also include a series of experiments designed to determine which types of instrumentation will prove most profitable for obtaining large numbers of strontium isotope analyses from fossils. In the second phase, tooth enamel from early hominin and non-hominin fauna will be analyzed in an attempt to answer questions about early hominin home ranges, migratory patterns, and social behavior. The intellectual merit of this study is that it will allow the team and others to begin addressing a number of previously intractable questions such as whether early human ancestors were migratory, whether the emergence of bipedalism was associated with increased home ranges compared to modern chimpanzees, and whether or not males or females dispersed from their natal groups and at what age dispersal occurred. Hence, this study offers the possibility of greatly enriching our understanding of early hominin ecology and life history, and in so doing, should better our understanding of human origins. Moreover, the study will build a large dataset on the distribution of strontium isotopes in soils, water, plants, and animals over a geologically diverse landscape which should prove useful for archaeologists, paleontologists, ecologists, geochemists, and forensic scientists who are interested in tracking the movements of humans and other organisms. The project's broader impact will include fostering extensive international collaboration between scientists from the United States, South Africa, and the United Kingdom. This will include hosting a small international workshop to disseminate the results of this study and to determine areas for future research. The project will also make a significant educational contribution, as it will provide postdoctoral and graduate training for students in the U.S. and South Africa from traditionally underrepresented groups.