Our team
Judith Sealy holds the South African Research Chair in Stable Isotopes, Archaeology and Palaeoenvironmental Studies, based in the Department of Archaeology at UCT. She also holds overall academic responsibility for the Stable Light Isotope Laboratory, used by researchers from a range of disciplines at UCT and other universities nationally and internationally. Sealy’s research uses isotopes to answer questions about the diet and economic base of human societies, from the emergence of modern humans to the development of hunter-gatherer, herder and farmer societies in southern Africa, and the start of of European colonization. Sealy holds or has held editorial positions with a number of journals. She is a Fellow of the Royal Society of South Africa and of UCT.
Professor Judith Sealy
Vincent Hare is an Earth scientist whose research interests span Cenozoic palaeoclimatology, palaeoenvironments, novel dating methods, past climate change, and the carbon cycle. His special research interest is the application of stable isotope geochemistry to understanding changes in ancient atmospheres, to better understand fossil and archaeological plants, and to refine predictions of future climate change. He holds degrees in both Physics and Archaeological Sciences from the University of Cape Town and Oxford (MSc, DPhil), where he was Clarendon Scholar. Hare is currently a member of the American Geophysical Union and the European Geophysical Union, Secretary of the Southern African Society for Quaternary Research, and Past Global Changes (PAGES) Early Career Representative for Africa.
Dr Vincent Hare
Julie Luyt obtained her PhD from the University of Cape Town. Her interests lie in the effects of environmental and climatic variables on stable carbon, nitrogen and oxygen isotopic ratios of fauna. Studies of contemporary fauna provide a baseline for the interpretation of analyses of archaeological and fossil animals. Her focus is on the winter rainfall zone in the southwestern part of Africa, where reconstruction of palaeoclimates and palaeoenvironments help to contextualize important archaeological sites that record evidence of early modern humans.
Dr Julie Luyt
Chris Harris is a geologist and geochemist and is Professor of Mineralogy and Geology. His research interest lies in stable isotopes in igneous rocks and hydrological systems, economic geology. He runs the high temperature geochemistry facility in Geology that has a number of extraction lines for the measurement of stable isotope ratios of O, C, and H in rock (silicates and carbonates), mineral and water samples.
Patricia Groenewald
Patricia Groenewald is the Senior Scientific Officer in the Stable Light Isotope Laboratory in the Department of Archaeology at UCT. She has a background in archaeology and is working towards her PhD. Her research focuses on a better understanding of bone collagen turnover in adult humans and the incorporation of dietary stable light isotopes throughout life.
Prof Chris Harris (affiliated, from Department of Geological Sciences)
Students at our lab
Learn more about the students currently working within our lab, and see list of our past students here.
Postdoc
Maximilian Spies
Maximilian Spies explores stable Iisotopes for archaeological and forensic purposes. His work examines the potential of stable isotopes (primarily C, N, S, O, Sr, and Pb) for archaeology and forensic science in Africa, with a focus on southern Africa, to develop isoscapes where possible. Results will be applicable to a range of questions including the identification of illicitly collected wild plants and animals, human migration and forensics, and archaeological studies of land use patterns and mobility.
Sangbaran Ghoshmaulik
Sangbaran completed his PhD at the Indian Institute of Technology Kharagpur, India. His research focuses on establishing protocols for triple oxygen isotope analysis of various geological samples using TILDAS, a cutting-edge technique in stable isotope studies, particularly for triple oxygen isotope analysis. Since TILDAS can analyse CO₂ as a sample gas, its application has been primarily limited to carbonate and CO₂ samples. However, his work aims to expand its scope to other natural samples, such as water and rock. Additionally, the research explores the characterisation of pollution sources in and around Cape Town using the triple oxygen isotopic composition of atmospheric CO2.
Anna Kudriavtseva
Anna Kudriavtseva is involved in research focused on triple oxygen isotope records from carbonates of ostrich eggshells collected from an archaeological sequence in the Boomplaas Cave. The work uses these data to reconstruct Quaternary paleoenvironmental conditions associated with human evolution and occupation of southern Africa.
PhD
Malefeu Lethuba
Malefeu Lethuba is a PhD candidate with research focusing on dental wear patterns (mesowear and microwear) and isotopic signatures in the teeth of modern and Middle Pleistocene elephants. The work explores diet flexibility and dietary shifts, while also helping to detangle the complex elephant phylogeny.
MSc
Siobhán Forbes-Wilkinson
Siobhán Forbes-Wilkinson holds an honours degree in archaeology from UCT. Her research involved the isotopic analysis of faunal and human bone samples from the Riet River in central South Africa. She analysed the δ13C, δ15N, and δ34S values of individuals from Type R populations in this study, to examine the usefulness of stable sulphur isotope ratios to determine the extent of reliance on riverine resources. She continues with this topic in her master’s research.
Gemma Poretti
Gemma Poretti examines high-resolution carbon isotopes in archaeological charcoal as a proxy for rainfall seasonality, aiming to capture seasonal variability during the Last Glacial Maximum and Last Glacial-Interglacial Transition. The work combines approaches from dendroclimatology, anthracology, and palaeoclimatology, and uses modern wood and charcoal from different seasonal rainfall zones as analogues to refine interpretations.
Amber Wilson
Amber Wilson’s Master’s research focuses on the use of stable light isotopes to investigate past Hunter Gatherer diets in the Polihali Dam Area, eastern Lesotho Highlands. The study analyses archaeological bone collagen from terrestrial mammals and freshwater fish, using sulphur (δ34S), carbon (δ13C), and nitrogen (δ15N) isotopes to explore the use of sulphur as a potential proxy for freshwater fish consumption. This research aims to contribute to the growing application of sulphur isotope analysis in archaeological studies.
Retired staff
Ian Newton
Dr Ian Newton has been an integral part of the lab for over 30 years, until his retirement in 2020. He started work as a technician, before obtaining his PhD in Botany from the University of the Western Cape. Newton has decades of knowledge about the inner workings of IRMS instrumentation, elemental analysis, as well as a brilliant memory of past samples and scholars.
John Lanham
John Lanham was for many years the Principal Scientific Officer in charge of the mass spectrometers and other equipment in the Stable Light Isotope Laboratory. From his appointment in 1981 until his retirement in 2018, he was the mainstay of the lab, building and repairing gas separation lines and other equipment and guiding users as to the best approaches for their needs. He continues to advise us when necessary.
Nik van der Merwe
Nikolaas van der Merwe is Emeritus Professor of Natural History in the Science Faculty at UCT. Nik is a forensic scientist who applies techniques from the natural sciences to the solution of archaeological problems. As a PhD student at Yale, he was a pioneer in the radiocarbon dating of iron alloys. At UCT, he founded the Stable Light Isotope Laboratory, where he pioneered stable isotope techniques to study the diets of prehistoric people by analysing their skeletons. With UCT students and colleagues, he applied these techniques in dietary studies of mammal-like reptiles of 200 million years ago in the Karoo, early hominins of 2 million years ago in South Africa and Tanzania, and contemporary wildlife in our National Parks.