Home

My research interests include archaeology in the American Southwest and the ecological context of human evolution. I have analyzed isotopes (carbon, oxygen, strontium) in teeth and bone, and conducted archaeological excavations and surveys, to investigate the diets and landscape movements of modern and ancient animals, humans, and early hominins. My research includes isotope analysis of turkeys from Ancestral Puebloan sites in northern New Mexico, strontium and other isotope analyses around the Cape Floral Region of South Africa as part of a project focused on the Pinnacle Point archaeological sites, connected to some of the earliest populations of modern Homo sapiens who lived in that vicinity around 165 to 40 thousand years ago (Copeland et al., 2016, Hodgkins et al., 2020, see Publications).

My 2011 paper in Nature documents the first direct evidence for landscape use among early hominins - the approximately 2-million-year-old species known as Paranthropus robustus and Australopithecus africanus - who lived in what is now the northeastern part of South Africa and were found in Sterkfontein and Swartkrans caves. My colleagues and I studied strontium isotopes in their teeth and concluded that it may have been females, and not males, that dispersed from the birth communities among these species (see Press for popular news coverage).

Strontium isotope ratios differ between bedrock types, and the unique strontium isotope ratio of a particular bedrock passes into the soils, plants, and animals that feed in that area. By measuring strontium isotope ratios in teeth that form at different ages within an animal, we can track movements of the animal as it migrates across different bedrocks. This is proving to be extremely useful in archaeology, paleontology, and modern ecology.

I helped to develop new methods for strontium isotope research, such as the use of laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) on teeth. I have experimented with methods for documenting biologically available strontium isotopes across modern and ancient landscapes. I analyzed strontium isotope ratios in the 36,000-year-old Hofmeyr skull from South Africa (Copeland et al. 2022), and I collected data on biologically available strontium isotope ratios across northern Tanzania (Janzen et al., 2020). (Publications)

From 2002-2006, and since 2014 I have worked at Los Alamos National Laboratory in New Mexico. In this fabulous natural setting, I have participated in excavations of many Ancestral Pueblo structures that date to ~1150-1550 AD, conducted surveys, documented cavate structures carved out of the soft volcanic tuff in canyon walls, and served as the archaeological lab director. On many of these projects I have worked with members of San Ildefonso and Santa Clara Pueblos, whose ancestral lands include the Pajarito Plateau, and whose current lands are adjacent to Los Alamos National Laboratory.

During my time as a graduate student at Rutgers University, I spent four field seasons excavating 1.8 million-year-old sites at Olduvai Gorge, Tanzania. In an effort to understand the potential diets of early hominins, I also spent a year studying the distribution of wild plant foods in Serengeti National Park, Ngorongoro Conservation Area, and Lake Manyara National Park, Tanzania (Copeland 2007, J. of Human Evolution). I have also compared the wild plant foods of these semi-arid East African savannas to the plant foods eaten by modern chimpanzees in other, generally moister habitats around Africa (Copeland 2009, J. of Human Evolution). I found that the fleshy fruits eaten by chimpanzees are sparse in modern semi-arid savannas of East Africa, especially compared to the greater number of fleshy fruits available in the moister savannas inhabited by "savanna chimpanzees". The abundant potential plant foods in modern East African semi-arid savannas are grasses, sedges, and Acacia pods that modern humans generally consider inedible unless cooked, but that baboons are known to depend upon in these habitats.