Doctoral Dissertation Research Award: use of Eggshell Isotopes for Mobility

This doctoral dissertation research will investigate human mobility by analyzing how a traditional group managed resource procurement in a marginal environment using isotopic analyses of ostrich eggshell. Understanding how groups of humans behaviorally adapted as they moved across the world is a core component to understanding how humans came to be the most populous large mammal on earth.

One way people adapted to a diversity of environments and changing climates was by adjusting their mobility patterns, resource catchment areas, and trade networks. This project will utilize the stable isotopes in ostrich eggshell to create paleoclimatic reconstructions while employing strontium isotope analysis to discern mobility patterns and identify possible trade networks, assessing how movement responded to climatic change.

Ostrich eggshell is an often-overlooked resource that is abundant in many archaeological deposits, signaling the importance of these eggs as a subsistence resource. Because ostrich eggshell is common in many archaeological sites, establishing standardized methods of collecting clean samples and of producing maps of bioavailable strontium on the landscapes of interest will allow researchers the benefit of generating data that can be easily compared and serve as a baseline for future projects.

Complex human behavior is linked to ostrich eggshell through use in bead making, symbolic engravings, and containers that carry or cache water in environments where water is sparse. The archaeological record significantly informs investigations into modern human origins and hunter-gatherer and pastoralist lifeways before and after European colonization and provides a wide range of ecosystems from which to study early human behavior and to explore how past human groups made their living.

To achieve the goals of this project adoctoral candidate at the University of California Davis will engineer the creation of a map illustrating regional biogenic strontium. This map will be a valuable tool as a baseline to this project as well as to other researchers in a variety of disciplines. McNeill will investigate mobility and resource catchment variables by comparing strontium values in archaeological ostrich eggshell to the map to assess the likely source of the eggshell, allowing one to discern how far groups were willing to travel or trade to obtain this valuable and versatile resource.

The researchers will develop and refine methods for extracting uncontaminated calcite from the eggshell to be processed for strontium isotope analysis to facilitate the spatial assessment. This uncontaminated shell material along with collagen from the organic component of the shell will then be sampled for stable isotope analysis to facilitate the paleoclimatic reconstruction of the study region.

Incorporating multiple lines of isotopic evidence enhances the interpretive power of these analyses for understanding human mobility and the food webs humans exploited, especially in the context of past environmental variability. The richness of data that can be gleaned from ostrich eggshells will provide researchers with another resource to employ in the mission to understand the human past.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.