Laboratory-based experimental research into the effect of diagenesis on heated bone: implications and improved tools for the characterisation of ancient fire

The use of fire is considered to be one of the most important cultural innovations in human evolution. Understanding the taphonomy of fire remains is an important prerequisite for valid interpretations of hominin fire-related behaviour. Presented here are the results of a series of laboratory-based experiments testing the effect of different pH conditions (acidic, neutral, alkaline) on the physical and chemical properties of heated bone (charred and combusted). By taking a fundamental-research approach the study gives insight into the specific effect of pH exposure and its underlying chemical processes, and provides data that can be applied to heated bone from any context and time period. Results show that diagenesis has a significant impact on the preservation potential of heated bones, as well as on the reliability of the analytical techniques used to reconstruct past heating conditions. The study provides reference data and a toolkit for the analysis of heated bone, that explicitly takes diagenesis into account, and in doing so offers a significant improvement to the accuracy with which we can reconstruct heating conditions and fire-related human behaviour in the past.Human Origin

3-years later… a reassessment of the need for something ‘in-between’

Welcome to the 2017 issue of INTER-SECTION: Innovative approaches by Junior Archaeological Researchers. In this issue, we present a total of five papers written by archaeology students in close collaboration with their academic referees, reflecting the wide range of both research and teaching at Leiden's Faculty of Archaeology from the the BA to the MA level

Integrating geoarchaeological techniques to reveal the invisible stratigraphy at Umhlatuzana rockshelter, South Africa: a grid-based approach

Umhlatuzana rockshelter is an archaeological site with an occupational record spanning the last ~70,000 years, covering the Middle Stone Age (MSA), Later Stone Age (LSA), and Iron Age. The deposits bearing Pleistocene archaeological assemblages at Umhlatuzana rockshelter appear homogeneous with no macroscopically visible stratigraphic boundaries. This means the integrity of the archaeological assemblages is difficult to ascertain. Moreover, the sedimentation rate, taphonomic history, and the environmental context across the sequence are unclear. This study aims to resolve these issues by integrating different geoarchaeological techniques in order to explore fine-resolution geochemical differentiations of the sediments that are macroscopically invisible. Samples were systematically retrieved from the western profile of the site following a grid-based sampling strategy and analysed for pH, elemental composition (XRF), and Magnetic Susceptibility. These methods were chosen because they provide insight into ‘invisible’ geoarchaeological dynamics, related to sediment input (geogenic and anthropogenic), taphonomy, and environmental conditions. Additionally, the results were integrated with preliminary micromorphological observations. Our study reveals a gradual change in the geochemistry of the deposits throughout the Pleistocene, related to a combination of environmental change and occupation intensity. Furthermore, the gradual change within the geochemical data indicates that no large-scale sediment mixing took place (contrary to previous suggestions), while small-scale mixing related to bioturbation is visible in the micromorphological thin sections. Our study offers a successful multi-proxy approach to systematically sample and analyse archaeological deposits at the macro and micro scale, integrating a variety of geoarchaeological techniques. The approach provides insight into the depositional and postdepositional history of the site, and allows questions of stratigraphic integrity, anthropogenic input, preservation, and environmental change to be addressed.NWOVidi 276-60-004Human Origin

Making the invisible stratigraphy visible: a grid-based, multi-proxy geoarchaeological study of Umhlatuzana rockshelter, South Africa

Umhlatuzana rockshelter is an archaeological site with an occupational record covering the Middle Stone Age, Later Stone Age, and Iron Age. The presence of both Middle and Later Stone Age assemblages makes Umhlatuzana the ideal location for the study of the MSA-LSA transition (20-40 ka) in southern Africa. This transitional period is characterized by important modifications in stone tool technology, from prepared core technology to a toolkit based on microlith production. These changes are argued to have occurred in response to changes in climate and environment leading up to the Last Glacial Maximum. The deposits bearing the transitional assemblages at Umhlatuzana rockshelter appear homogeneous with no visible stratigraphic boundaries. This study integrates geoarchaeological techniques in order to explore fine-resolution geochemical differentiations of the sediments that are macroscopically invisible, and that will provide insight into (post-)depositional processes over time. Samples were systematically retrieved from the western profile of the site following a grid-based sampling strategy and analyzed for pH, elemental composition (XRF), and Magnetic Susceptibility. Additionally, the results were integrated with preliminary micromorphological observations. Our study reveals a steady, gradual change in the geochemistry of the deposits throughout the Pleistocene, related to a combination of environmental change and occupation intensity. We suggest that the part of the sequence reported to bear Middle to Later Stone Age transitional industries is characterized by wetter environmental conditions compared to the underlying deposits. Additionally, we support results from previous studies that excluded large scale post-depositional movement of the sedimentary sequence. Our study offers a successful multi-proxy approach to systematically sample and study archaeological deposits at the macro and micro scale, integrating a variety of geoarchaeological techniques. The approach provides insight into the depositional and post-depositional history of the site, and allows for questions of stratigraphic integrity, anthropogenic input, preservation, and environmental change to be addressed.Thrombosis and Hemostasi

Laboratory-based experimental research into the effect of diagenesis on heated bone: implications and improved tools for the characterisation of ancient fire

The use of fire is considered to be one of the most important cultural innovations in human evolution. Understanding the taphonomy of fire remains is an important prerequisite for valid interpretations of hominin fire-related behaviour. Presented here are the results of a series of laboratory-based experiments testing the effect of different pH conditions (acidic, neutral, alkaline) on the physical and chemical properties of heated bone (charred and combusted). By taking a fundamental-research approach the study gives insight into the specific effect of pH exposure and its underlying chemical processes, and provides data that can be applied to heated bone from any context and time period. Results show that diagenesis has a significant impact on the preservation potential of heated bones, as well as on the reliability of the analytical techniques used to reconstruct past heating conditions. The study provides reference data and a toolkit for the analysis of heated bone, that explicitly takes diagenesis into account, and in doing so offers a significant improvement to the accuracy with which we can reconstruct heating conditions and fire-related human behaviour in the past.</p

NPO Radio 1: Nieuws & Co: Neanderthalers waren meer bezig met koken dan we dachten

Neanderthalers kookten en bewerkten hun eten al veel uitgebreider dan gedacht. Ze aten daarom allerlei soorten planten, zelfs als die niet eetbaar waren. Britse wetenschappers hebben dit ontdekt toen ze 12 tot 70 duizend jaar oude kookresten analyseerden die zijn gevonden in Griekenland en Irak. Femke Reidsma is promovendus bij de menselijke evolutie-groep aan de Universiteit Leiden en vertelt erover bij Nieuws en Co. Human Origin

How to deal with homogeneous stratigraphies: excavation, sampling, and analysis strategies at Umhlatuzana Rockshelter, Kwazulu-Natal, South Africa

To ensure proper context control for archaeological samples, it is crucial that excavations determine and,where possible, follow the natural stratigraphic subdivisions in a sedimentary sequence. In cases with a single,unchanging source of sedimentary input, this may pose challenges. We present our strategies to deal with a>2 m deep homogeneous Pleistocene stratigraphy at Umhlatuzana rockshelter in South Africa, yieldingarchaeological remains from the Middle Stone Age. The site was originally excavated during a rescue project in 5–10 cm deep artificial spits for lack of visible stratigraphy. We revisited the shelter in 2018 and 2019. We integrate current standard practice such as piece-plotting archaeological materials with digital methods such as cluster analysis and geoarchaeological analyses (e.g., micromorphology, sedimentological analyses, geochemical analyses) to track the different sources of sedimentary input. We also develop an intensive sediment sampling strategy to illuminate geochemical variation within the sequence and postdepositional alterations affecting preservation conditions. We manage to reconstruct a natural stratigraphy of the site combining these methodologies, resulting in a radically changed understanding of the stratigraphy, depositional environment, and mechanisms of postdepositional disturbance. NWOVidi 276-60-004Human Origin

Aller Anfang is schwer

It is with great pleasure that we present to you the second volume of INTER-SECTION: Innovative Approaches by Junior Archaeological Researchers. This journal emanates from the observation that student research, which is carried out conforming to high theoretical and methodological standards, is generally only read by a handful of people. Our aim is to make student research performed at the Faculty of Archaeology, Leiden University, available to a broader public by stimulating these junior archaeologists to channelize their ‘fresh’ and innovative ideas and practice into short, focused articles. Reviews conducted by renowned external scholars further aid in the improvement of these papers and provide invaluable experience for a future academic career. The product of another cycle of writing, reviewing, rewriting and editing lies here in front of you. We wish you a happy and interesting read with our present volume

Charred bone : Physical and chemical changes during laboratory simulated heating under reducing conditions and its relevance for the study of fire use in archaeology

In order to gain insight into the timing and nature of hominin fire use, the effect of heat on the physical and chemical properties of the materials entering the archaeological record needs to be understood. The present study concerns the fire proxy heated bone. Two types of heating can be distinguished: combustion (or burning, with oxygen) and charring (without oxygen), for both of which the formation of char is the first step. We performed a series of controlled laboratory-based heating experiments, in reducing conditions (i.e. charring), covering a broad temperature range (20–900 °C), and applied a variety of different analytical techniques. Results indicate that charred bone shows a distinctly different thermal alteration trajectory than combusted bone, which has implications for the suitability of the different analytical techniques when identifying and determining past heating conditions (charring vs. combustion; temperature) of heated bone from archaeological contexts. Combined, the reference data and techniques presented in this study can be used as a robust toolkit for the characterisation of archaeological charred bone from various ages and contexts

Charred bone : Physical and chemical changes during laboratory simulated heating under reducing conditions and its relevance for the study of fire use in archaeology

In order to gain insight into the timing and nature of hominin fire use, the effect of heat on the physical and chemical properties of the materials entering the archaeological record needs to be understood. The present study concerns the fire proxy heated bone. Two types of heating can be distinguished: combustion (or burning, with oxygen) and charring (without oxygen), for both of which the formation of char is the first step. We performed a series of controlled laboratory-based heating experiments, in reducing conditions (i.e. charring), covering a broad temperature range (20–900 °C), and applied a variety of different analytical techniques. Results indicate that charred bone shows a distinctly different thermal alteration trajectory than combusted bone, which has implications for the suitability of the different analytical techniques when identifying and determining past heating conditions (charring vs. combustion; temperature) of heated bone from archaeological contexts. Combined, the reference data and techniques presented in this study can be used as a robust toolkit for the characterisation of archaeological charred bone from various ages and contexts