Search

Your search keyword '"Julia Lee-Thorp"' showing total 4 results
Start Over Author "Julia Lee-Thorp" Publication Year Range Last 3 years
4 results on '"Julia Lee-Thorp"'

2. Micromilling vs hand drilling in stable isotope analyses of incremental carbonates: The potential for δ13c contamination by embedding resin

Author

Tansy Branscombe, Julia Lee‐Thorp, Rick Schulting, and Melanie Leng

Subjects
Organic Chemistry, Spectroscopy, Analytical Chemistry
Abstract

Rationale Embedding resins are commonly used to facilitate high-resolution sampling for stable isotope analysis but anomalous δ13C values have been observed in some cases. Here we compare the results of microsampling strategies for hand-drilled versus resin-embedded micromilled samples from the same marine shells to assess whether resin contamination is implicated in δ13C spikes. The comparison allows assessment of the relative benefits for spatial resolution, seasonal range for both δ18O and δ13C, and sample failure rates. Methods Hand-drilled samples were obtained from two bivalve shells (Spisula sachalinensis), corresponding to micromilled samples on the same shells where high δ13C spikes were observed. All carbonate powders were analysed using a dual-inlet Isoprime mass spectrometer and Multiprep device. Results from both sample sets were compared statistically. Results No anomalous high δ13C values and no failures due to insufficient gas were observed in the hand-drilled samples in contrast to the embedded micromilled sequences. Spatial resolution was reduced (~2.5×) in the former compared with the latter, resulting in a small reduction in the total range observed in the micromilled δ13C and δ18O values. Reduced sampling resolution between the two datasets was only significant for δ18O. Conclusions For S. sachalinensis (as with other similar bivalves), rapid growth mitigates the reduced sampling resolution of hand drilling and does not significantly impact observed isotopic range and seasonal patterning. Occurrence of anomalous δ13C values were eliminated and failure rates due to insufficient sample size greatly reduced in the hand-drilled dataset. We can find no other explanation for the occurrence of δ13C spikes than contamination by the embedding agent. We conclude that the logistical and interpretational benefits of careful hand drilling may be preferable to resin embedding for micromilling in marine shells, corals or speleothems where growth rate is rapid and the highest resolution is not required.

Published
2022

3. The Oxford Handbook of the Archaeology of Diet

Author

Julia Lee-Thorp, M. Anne Katzenberg, Julia Lee-Thorp, and M. Anne Katzenberg

Subjects
Diet--History, Prehistoric peoples--Food, Food habits--History, Archaeology
Abstract

Humans are unique among animals for the wide diversity of foods and food preparation techniques that are intertwined with regional cultural distinctions around the world. The Oxford Handbook of the Archaeology of Diet explores evidence for human diet from our earliest ancestors through the dispersal of our species across the globe. As populations expanded, people encountered new plants and animals and learned how to exploit them for food and other resources. Today, globalization aside, the results manifest in a wide array of traditional cuisines based on locally available indigenous and domesticated plants and animals. How did this complexity emerge? When did early hominins actively incorporate animal foods into their diets, and later, exploit marine and freshwater resources? What were the effects of reliance on domesticated grains such as maize and rice on past populations and the health of individuals? How did a domesticated plant like maize move from its place of origin to the northernmost regions where it can be grown? Importantly, how do we discover this information, and what can be deduced about human health, biology, and cultural practices in the past and present? Such questions are explored in thirty-three chapters written by leading researchers in the study of human dietary adaptations. The approaches encompass everything from information gleaned from comparisons with our nearest primate relatives, tools used in procuring and preparing foods, skeletal remains, chemical or genetic indicators of diet and genetic variation, and modern or historical ethnographic observations. Examples are drawn from across the globe and information on the research methods used is embedded within each chapter. The Handbook provides a comprehensive reference work for advanced undergraduate and graduate students and for professionals seeking authoritative essays on specific topics about diet in the human past.

Published
2024

Catalog

Books, media, physical & digital resources
See catalog results