Reproduction of melting behavior for vitrified hillforts based on amphibolite, granite, and basalt lithologies
Abstract European Bronze and Iron Age vitrified hillforts have been known since the 1700s, but archaeological interpretations regarding their function and use are still debated. We carried out a series of experiments to constrain conditions that led to the vitrification of the inner wall rocks in th...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2021-01-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-020-80485-w |
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| author | John S. McCloy José Marcial Jack S. Clarke Mostafa Ahmadzadeh John A. Wolff Edward P. Vicenzi David L. Bollinger Erik Ogenhall Mia Englund Carolyn I. Pearce Rolf Sjöblom Albert A. Kruger |
| author_facet | John S. McCloy José Marcial Jack S. Clarke Mostafa Ahmadzadeh John A. Wolff Edward P. Vicenzi David L. Bollinger Erik Ogenhall Mia Englund Carolyn I. Pearce Rolf Sjöblom Albert A. Kruger |
| author_sort | John S. McCloy |
| collection | DOAJ |
| description | Abstract European Bronze and Iron Age vitrified hillforts have been known since the 1700s, but archaeological interpretations regarding their function and use are still debated. We carried out a series of experiments to constrain conditions that led to the vitrification of the inner wall rocks in the hillfort at Broborg, Sweden. Potential source rocks were collected locally and heat treated in the laboratory, varying maximum temperature, cooling rate, and starting particle size. Crystalline and amorphous phases were quantified using X-ray diffraction both in situ, during heating and cooling, and ex situ, after heating and quenching. Textures, phases, and glass compositions obtained were compared with those for rock samples from the vitrified part of the wall, as well as with equilibrium crystallization calculations. ‘Dark glass’ and its associated minerals formed from amphibolite or dolerite rocks melted at 1000–1200 °C under reducing atmosphere then slow cooled. ‘Clear glass’ formed from non-equilibrium partial melting of feldspar in granitoid rocks. This study aids archaeological forensic investigation of vitrified hillforts and interpretation of source rock material by mapping mineralogical changes and glass production under various heating conditions. |
| first_indexed | 2024-12-19T09:00:47Z |
| format | Article |
| id | doaj.art-31320ea7091548e0a36e406b6bc90cbd |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-19T09:00:47Z |
| publishDate | 2021-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-31320ea7091548e0a36e406b6bc90cbd2022-12-21T20:28:29ZengNature PortfolioScientific Reports2045-23222021-01-0111111810.1038/s41598-020-80485-wReproduction of melting behavior for vitrified hillforts based on amphibolite, granite, and basalt lithologiesJohn S. McCloy0José Marcial1Jack S. Clarke2Mostafa Ahmadzadeh3John A. Wolff4Edward P. Vicenzi5David L. Bollinger6Erik Ogenhall7Mia Englund8Carolyn I. Pearce9Rolf Sjöblom10Albert A. Kruger11School of Mechanical and Materials Engineering, Washington State UniversitySchool of Mechanical and Materials Engineering, Washington State UniversityDepartment of Materials Science and Engineering, University of SheffieldSchool of Mechanical and Materials Engineering, Washington State UniversitySchool of the Environment, Washington State UniversityMuseum Conservation Institute, Smithsonian InstitutionMaterials Science and Engineering Program, Washington State UniversityThe Archaeologists, National Historical Museums (SHM)The Archaeologists, National Historical Museums (SHM)Pacific Northwest National LaboratoryLuleå University of TechnologyUS Department of EnergyAbstract European Bronze and Iron Age vitrified hillforts have been known since the 1700s, but archaeological interpretations regarding their function and use are still debated. We carried out a series of experiments to constrain conditions that led to the vitrification of the inner wall rocks in the hillfort at Broborg, Sweden. Potential source rocks were collected locally and heat treated in the laboratory, varying maximum temperature, cooling rate, and starting particle size. Crystalline and amorphous phases were quantified using X-ray diffraction both in situ, during heating and cooling, and ex situ, after heating and quenching. Textures, phases, and glass compositions obtained were compared with those for rock samples from the vitrified part of the wall, as well as with equilibrium crystallization calculations. ‘Dark glass’ and its associated minerals formed from amphibolite or dolerite rocks melted at 1000–1200 °C under reducing atmosphere then slow cooled. ‘Clear glass’ formed from non-equilibrium partial melting of feldspar in granitoid rocks. This study aids archaeological forensic investigation of vitrified hillforts and interpretation of source rock material by mapping mineralogical changes and glass production under various heating conditions.https://doi.org/10.1038/s41598-020-80485-w |
| spellingShingle | John S. McCloy José Marcial Jack S. Clarke Mostafa Ahmadzadeh John A. Wolff Edward P. Vicenzi David L. Bollinger Erik Ogenhall Mia Englund Carolyn I. Pearce Rolf Sjöblom Albert A. Kruger Reproduction of melting behavior for vitrified hillforts based on amphibolite, granite, and basalt lithologies Scientific Reports |
| title | Reproduction of melting behavior for vitrified hillforts based on amphibolite, granite, and basalt lithologies |
| title_full | Reproduction of melting behavior for vitrified hillforts based on amphibolite, granite, and basalt lithologies |
| title_fullStr | Reproduction of melting behavior for vitrified hillforts based on amphibolite, granite, and basalt lithologies |
| title_full_unstemmed | Reproduction of melting behavior for vitrified hillforts based on amphibolite, granite, and basalt lithologies |
| title_short | Reproduction of melting behavior for vitrified hillforts based on amphibolite, granite, and basalt lithologies |
| title_sort | reproduction of melting behavior for vitrified hillforts based on amphibolite granite and basalt lithologies |
| url | https://doi.org/10.1038/s41598-020-80485-w |
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