McCloy John S, Marcial José, Clarke Jack S, Ahmadzadeh Mostafa, Wolff John A, Vicenzi Edward P, Bollinger David L, Ogenhall Erik, Englund Mia, Pearce Carolyn I, Sjöblom Rolf, Kruger Albert A
School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, USA.
Materials Science and Engineering Program, Washington State University, Pullman, WA, USA.
Sci Rep. 2021 Jan 14;11(1):1272. doi: 10.1038/s41598-020-80485-w.
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.
自18世纪以来，人们就已知道欧洲青铜时代和铁器时代的玻璃化山丘堡垒，但关于其功能和用途的考古学解释仍存在争议。我们进行了一系列实验，以确定导致瑞典布罗堡山丘堡垒内壁岩石玻璃化的条件。在当地采集了潜在的源岩，并在实验室中进行热处理，改变最高温度、冷却速率和初始颗粒大小。使用X射线衍射对加热和冷却过程中的原位以及加热和淬火后的非原位结晶相和非晶相进行了定量分析。将获得的纹理、相和玻璃成分与来自墙壁玻璃化部分的岩石样本以及平衡结晶计算结果进行了比较。“深色玻璃”及其相关矿物由角闪岩或粗玄岩在还原气氛下于1000-1200°C熔化后缓慢冷却形成。“透明玻璃”由花岗岩类岩石中长石的非平衡部分熔融形成。这项研究通过绘制各种加热条件下的矿物学变化和玻璃生产情况，有助于对玻璃化山丘堡垒进行考古法医调查以及对源岩材料进行解释。
