Knapping force as a function of stone heat treatment.
We propose a quantitative framework for understanding the knapping force requirements imposed by different raw materials in their unheated and heat-treated states. Our model interprets stone tool knapping as being the result of cracks formed during the first impact with a hammer stone, followed by c...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2022-01-01
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| Series: | PLoS ONE |
| Online Access: | https://doi.org/10.1371/journal.pone.0278643 |
| _version_ | 1811177221299109888 |
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| author | Klaus G Nickel Patrick Schmidt |
| author_facet | Klaus G Nickel Patrick Schmidt |
| author_sort | Klaus G Nickel |
| collection | DOAJ |
| description | We propose a quantitative framework for understanding the knapping force requirements imposed by different raw materials in their unheated and heat-treated states. Our model interprets stone tool knapping as being the result of cracks formed during the first impact with a hammer stone, followed by continued stressing of these cracks that eventually leads to flake detachment. We combine bending strength, indentation fracture resistance and "Griffith" crack lengths of flint and silcrete to obtain functions identifying critical forces for flaking without or after heat treatment. We argue that these forces are a key factor for understanding the "knappability" of different raw materials, because only forces with 100N or less can be used for very precise strike control. Our model explains for the first time why experimental knappers frequently observe that flint (a stronger material, which, in our case, has a strength above 100 MPa) is easier to knap than silcretes (which is relatively weaker with strength values at or below 60 MPa). Our findings allow for understanding the differences between heat-treated and untreated flint and silcrete in terms of knapping quality, and they allow to compare the qualities of different raw materials. |
| first_indexed | 2024-04-10T22:58:06Z |
| format | Article |
| id | doaj.art-7902e85ad37d439f901e1421a601112c |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-04-10T22:58:06Z |
| publishDate | 2022-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-7902e85ad37d439f901e1421a601112c2023-01-14T05:31:50ZengPublic Library of Science (PLoS)PLoS ONE1932-62032022-01-011712e027864310.1371/journal.pone.0278643Knapping force as a function of stone heat treatment.Klaus G NickelPatrick SchmidtWe propose a quantitative framework for understanding the knapping force requirements imposed by different raw materials in their unheated and heat-treated states. Our model interprets stone tool knapping as being the result of cracks formed during the first impact with a hammer stone, followed by continued stressing of these cracks that eventually leads to flake detachment. We combine bending strength, indentation fracture resistance and "Griffith" crack lengths of flint and silcrete to obtain functions identifying critical forces for flaking without or after heat treatment. We argue that these forces are a key factor for understanding the "knappability" of different raw materials, because only forces with 100N or less can be used for very precise strike control. Our model explains for the first time why experimental knappers frequently observe that flint (a stronger material, which, in our case, has a strength above 100 MPa) is easier to knap than silcretes (which is relatively weaker with strength values at or below 60 MPa). Our findings allow for understanding the differences between heat-treated and untreated flint and silcrete in terms of knapping quality, and they allow to compare the qualities of different raw materials.https://doi.org/10.1371/journal.pone.0278643 |
| spellingShingle | Klaus G Nickel Patrick Schmidt Knapping force as a function of stone heat treatment. PLoS ONE |
| title | Knapping force as a function of stone heat treatment. |
| title_full | Knapping force as a function of stone heat treatment. |
| title_fullStr | Knapping force as a function of stone heat treatment. |
| title_full_unstemmed | Knapping force as a function of stone heat treatment. |
| title_short | Knapping force as a function of stone heat treatment. |
| title_sort | knapping force as a function of stone heat treatment |
| url | https://doi.org/10.1371/journal.pone.0278643 |
| work_keys_str_mv | AT klausgnickel knappingforceasafunctionofstoneheattreatment AT patrickschmidt knappingforceasafunctionofstoneheattreatment |