| 1. |
- Sjöblom, Rolf, et al.
(författare)
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Assessment of the reason for the vitrification of a wall at a hillfort. The example of Broborg in Sweden
- 2022
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Ingår i: Journal of Archaeological Science. - : Elsevier. - 2352-409X .- 2352-4103. ; 43
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Tidskriftsartikel (refereegranskat)abstract
- It was discovered around 250 years ago that some of the rock material in the walls of some hillforts had been subjected to such high temperature that it had vitrified. This prompted a debate as to the reason for it that is still going on today: did the vitrification come about as a result of hostile action, by accident, or for the purpose of constructing the fort? The present paper is based on the recognition that hillforts are different, and therefore should be evaluated individually. All identifiable factors of interest should be included, and especially those that might disprove any alternative. Thus, incentives, competence and petrographic aspects were evaluated for the hillfort named Broborg (dated to the Migration Period, in Sweden A.D. 400–550), and it is concluded that the vitrification here came about for the purpose of constructing the fort.
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| 2. |
- Vicenzi, Edward P., et al.
(författare)
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Major to trace element imaging and analysis of iron age glasses using stage scanning in the analytical dual beam microscope (tandem)
- 2022
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Ingår i: Heritage Science. - : Springer. - 2050-7445. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Dark and clear silicate glasses formed during an iron age vitrification event ≈ 1500 years ago at the Broborg hillfort near Uppsala, Sweden have been analyzed using a scanning electron microscope equipped with a micro-X-ray fluorescence (μXRF) spectrometer. Correlated µXRF and electron beam-induced energy dispersive spectrometry (EDS) X-ray maps were collected via stage-scanning at constant velocity. This coupled procedure represents a new approach for the cultural heritage community to conduct analytical studies of archaeometric specimens composed of metal, ceramic, or mixed inorganic/organic materials, where major and trace element compositions are registered in space for areas up to the centimeter-length scale at micrometer-scale resolution. Overview images were used to select areas for EDS beam scan maps correlated with multispectral cathodoluminescence (CL) imaging and co-located quantitative EDS and μXRF point analysis. Fe, Ca, Mg, Ti, P, Mn, Zr, Zn, and Y are enriched in the dark glass, while Si, Al, K, Na, Ba, Sr, Rb, and Ga are enriched in the clear glass. Unmelted material is comprised predominately of quartz (SiO2) along with trace apatite (Ca5(PO4)3[Cl,OH]) and zircon (ZrSiO4). Multivariate statistical analysis was used to measure the area fractions of high variance components while lower variance components represented phase mixtures. Differences between calculated melt viscosities for the glass compositions are consistent with field and laboratory observations. Coupled large area EDS and μXRF imaging shows significant promise for informed selection of higher spatial resolution and higher sensitivity follow-up studies, e.g., those performed using synchrotron analysis.
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