Knapping force as a function of stone heat treatment

Nickel, Klaus G.; Schmidt, Patrick

doi:10.1371/journal.pone.0278643

Cited by 5 publications

(1 citation statement)

References 51 publications

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“…The monitored heat treatment of lithic materials is a procedure often associated with the improvement of the knapping properties of silicious rocks, the control of the knapper over the end-product (e.g., [66,[74][75][76]), or with increases in edge sharpness [60]. In other cases, heat treatment is associated with aesthetic motivations (e.g., [77][78][79]).…”

Section: Lithic Heat Treatmentmentioning

confidence: 99%

Heat Treatment of Flint at the Late Neanderthal Site Sesselfelsgrotte (Germany)

Agam,

Hattermann,

Pinkas

et al. 2023

Quaternary

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We examined lithic artifacts from the late Neanderthal site Sesselfelsgrotte (Bavaria, Germany) in order to evaluate the possibility of fire use and intentional flint heat treatment performed by late Neanderthals. We analyzed 1113 flint pieces from the G-layer complex (~60 to 45 kya; Micoquian) and 946 from the lower-layer complex (~115 to 70 kya; Mousterian). Based on macroscopic traits associated with the exposure of flint to heat and fire, we assigned artifacts to one of three groups: burnt, unburnt, and possibly intentionally heated. Our results show that while both complexes demonstrate the clear presence of fire, fire is more common in the younger G-layer complex. Moreover, possibly intentionally heated pieces are significantly more frequent in the G-layer complex, especially among the tools and specifically among side scrapers, suggesting a link between heat treatment and the production of these tools, most probably due to their functional and cultural significance. We therefore suggest that the flint in the G-layer complex of Sesselfelsgrotte underwent intentional heat treatment. The proportions of burnt flint artifacts in both complexes suggest an intensification in fire use at the site over time, while the appearance of possibly intentionally heated artifacts in the G-layer complex suggests the development of this advanced pyrotechnology by Neanderthals sometime between these two timeframes. Our results are supported by sedimentological and faunal data. We view these results as further indication of the advanced cognitive and technological capabilities of Neanderthals, which did not fall short of those of early modern humans.

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Section: Lithic Heat Treatmentmentioning

confidence: 99%

Heat Treatment of Flint at the Late Neanderthal Site Sesselfelsgrotte (Germany)

Agam,

Hattermann,

Pinkas

et al. 2023

Quaternary

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Explaining the Increase in “High-quality Chert” in the Early Upper Paleolithic Artifacts in Southern Jordan: Quantitative Examination of Chert Mechanical Properties and Fracture Predictability

Suga,

Tsukada,

Tarawneh

et al. 2023

J Paleo Arch

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In the studies of aked stone tools, the "quality" of lithic raw material has often been assessed from a viewpoint of its suitability to lithic production, and several studies quanti ed such raw material qualities by measuring mechanical properties of several different rocks like obsidian, chert, and basalt. To advance this approach, this study aims to quantify variations in the quality of chert, which is usually based on the difference in grain-size, e.g., ne-grained chert as "high-quality". For this purpose, we measured two types of hardness, i.e., the rebound hardness by Schmidt Hammer and the Rockwell Hardness (HRC), by using chert samples from southern Jordan, where the use of ne-grained chert increased in the Early Upper Paleolithic (Ahmarian) in association with the development of bladelet technology. The results indicate that ne-grained chert has greater fracture predictability and particularly suitable for the production of bladelets. However, ne-grained chert in southern Jordan suffer from abundant internal fractures and was not used as often as medium-grained chert for Levallois products and robust blades in the Late Middle and Initial Upper Paleolithic. Thus, explaining the prehistoric selectivity of lithic raw materials need to consider fracture predictability as well as other factors, such as actual conditions of occurrences and lithic production technology.

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The driving force behind tool-stone selection in the African Middle Stone Age

Schmidt,

Pappas,

Porraz

et al. 2024

Proc. Natl. Acad. Sci. U.S.A.

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In the Stone Age, the collection of specific rocks was the first step in tool making. Very little is known about the choices made during tool-stone acquisition. Were choices governed by the knowledge of, and need for, specific properties of stones? Or were the collected raw materials a mere by-product of the way people moved through the landscape? We investigate these questions in the Middle Stone Age (MSA) of southern Africa, analyzing the mechanical properties of tool-stones used at the site Diepkloof Rock Shelter. To understand knapping quality, we measure flaking predictability and introduce a physical model that allows calculating the relative force necessary to produce flakes from different rocks. To evaluate their quality as finished tools, we investigate their resistance during repeated use activities (scraping or cutting) and their strength during projectile impacts. Our findings explain tool-stone selection in two emblematic periods of the MSA, the Still Bay and Howiesons Poort, as being the result of a deep understanding of these mechanical properties. In both cases, people chose those rocks, among many others, that allowed the most advantageous trade-off between anticipated properties of finished tools and the ease of acquiring rocks and producing tools. The implications are an understanding of African MSA toolmakers as engineers who carefully weighed their choices taking into account workability and the quality of the tools they made.

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Knapping force as a function of stone heat treatment

Cited by 5 publications

References 51 publications

Heat Treatment of Flint at the Late Neanderthal Site Sesselfelsgrotte (Germany)

Heat Treatment of Flint at the Late Neanderthal Site Sesselfelsgrotte (Germany)

Explaining the Increase in “High-quality Chert” in the Early Upper Paleolithic Artifacts in Southern Jordan: Quantitative Examination of Chert Mechanical Properties and Fracture Predictability

The driving force behind tool-stone selection in the African Middle Stone Age

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