PhD (M/F) in lithic technology specialized on the invention of pressure micro-blade in North-East Asia

The candidate will be funded by the CNRS. The PhD will take place at Toulouse Jean Jaurès University, within the TRACES-UMR 5608 laboratory (Travaux et Recherches Archéologiques sur les Cultures, les Espaces et les Sociétés). The PhD will be directed by Nicolas Teyssandier (HDR CNRS researcher, TRACES), with co-direction by Yan-Axel Gomez Coutouly (CNRS-UMR ArchAm).
With over 100 permanent members and state-of-the-art equipment, UMR 5608 TRACES is one of France's and Europe's leading centers for archaeological research and training. Among other themes, cultural lithic technology occupies a very important place. TRACES is one of France's leading research centers in this field, bringing together both scientific and technical expertise. Part of the ArchéoSciences platform and its equipment is specifically dedicated to lithic technology. The candidate will benefit from all the logistical support provided by TRACES, and will have a dedicated space within the structure. At TRACES, the PhD student will be part of the SMP3C (Sociétés et Milieux des Populations de Chasseurs-Cueilleurs-Collecteurs) research team, and his/her research work will contribute to themes 1 “Actualist approaches: reference systems, experimentation, taphonomy” and 3 “From characterization of technical systems to reconstruction of evolutionary dynamics”.
This research will alternate between laboratory work in France, and study visits to Asia to collect certain primary data.

The invention of microblade pressure debitage: new methodological approaches and archaeological implications for Homo sapiens 'adaptation to the Northern Latitude of Asia during the Upper Pleistocene
General context of the PhD
Microlithization is a fundamental trend in the evolution of techniques throughout the Upper Pleistocene and the Holocene. Observed in many Homo sapiens traditions, it is generally defined by a sharp reduction in the size and an increase in standardization of stone tools. Such changes are usually interpreted as a form of adaptation to a range of contrasting environmental and social selective forces. Thus, throughout the Upper Pleistocene, microlithic tools developed on every continent with or without contacts between their makers.
This doctoral thesis focuses on a major technical innovation specific to bladelet productions that appears to be particularly successful in North-East Asia and Beringia. Also known as " microblade technology ", it was first identified in the Yubetsu river basin, on the island of Hokkaido, in Japan. As far as research is concerned, the Yubetsu method is one of the earliest examples of serial pressure bladelet detachment. It is found over a vast geographical area, covering all of North-East Asia and Beringia.
The French school of lithic technology has made a significant contribution to the study of pressure debitage through technical reading of archaeological remains and the building of experimental comparative collections essential for interpretation. These methodological achievements, subsequently adopted in different geographical and chronological contexts, were instrumental in identifying technological traits typical of pressure debitage. While the French school has succeeded in doing so qualitatively, distinguishing between bladelets detached by different debitage techniques require additional quantitative support. Qualitative criteria may not always be obvious when confronted with a archaeological sample size, especially for the simplest pressure methods and the most basic bladelet cores. As a result, there is still a great deal of disagreement as to how to establish clear criteria for the recognition of this technical innovation.
Furthermore, the question of the origin and distribution of North Asian Upper Palaeolithic bladelet pressure debitage is now crucial to understanding the settlement/repopulation of northern Asia and Beringia starting from the Last Glacial Maximum. Two major problems remain, and will be goals prioritized in this PhD project:
1) Earliest examples of microblade pressure flaking (i.e. pre-dating the Last Glacial Maximum) described in the literature as potential origins for this technology in Korea, Japan and Mongolia, pose serious identification problems and need to be reviewed with new analytical criteria ;
2) pressure debitage lacks a robust definition based on clear criteria. So far, the latter are neither published nor shared and are not the subject of an international consensus. This is the main obstacle to be overcome, and can only be done by combining approaches from different disciplines (lithic technology, geometric morphometry, deep learning).
Candidate's tasks
The candidate will first develop a suitable methodology to identify, in a robust and unbiased way, the pressure debitage technique. The first step will be to develop an exploratory method based primarily on 2D analysis of bladelet contours. Morphometric tools will be used to train models capable of identifying the experimental material (rectilinearity and edge parallelism indices; elliptical Fourier transforms and multivariate discriminant analyses in particular). 2D analysis of the contours of experimental bladelets, via Fourier elliptic transforms and discriminant analyses, reproducible and state-of-the-art using the Momocs package and, more broadly, the R environment, will aim to objectivize what technologists perceive about the extreme regularity of specimens obtained by pressure compared to their counterparts detached by direct or indirect percussion. Morphometric data on bladelet obtained using geometric morphometry tools will be statistically processed. This novel aspect will be the subject of collaboration with V. Bonhomme and A. Evin (UMR ISEM), bioarchaeologists and statisticians. Statistical analyses will explore the morphometric variation of bladelets, compare the different modes of production (percussion/pressure) and, if differences are sufficiently contrasted, develop identification tools. These analyses will be complemented by deep learning approaches (convolutional neural networks) with the aim of overcoming morphometric approaches and, in addition, eliminating acquisition biases. Once this method has been developed and tested on experimental material, it will be applied to the archaeological record of North-East Asia (South Korea, Japan, Mongolia) in order to address the initial question and provide robust criteria for establishing formal evidence of pressure detachment techniques during the Upper Palaeolithic.
The PhD student will be supervised by N. Teyssandier at the University of Toulouse Jean Jaurès (Ecole doctorale TESC), with co-supervision by Y.A. Gomez Coutouly. He/she will be attached to the TRACES laboratory within the SMP3C research team and will collaborate on this thesis with members of the MITI-CNRS Under Pressure project under the direction of N. Teyssandier. He/she will first of all follow up on the analyses carried out on the experimental lithic series by training on 2D contour analyses and deep learning. Once these protocols have been guaranteed and used routinely, leading to a methodological publication in an international journal, he/she will carry out mission in South Korea, Japan and Mongolia to study archaeological collections of the reference sites. The cross-referencing of these results will lead to a robust method for identifying the pressure debitage technique and adressing the question of the origin and diffusion of this innovation in the Far North of Asia. The acquisition of skills and interactions with the specialists involved in the project will provide the candidate with a high level of multi- and interdisciplinary training.