engleski

Early medieval bog iron ore smelting process: a case study of Virje – Volarski breg (NW Croatia)

Main goal of this study is to provide first results of geochemical and mineralogical analyses of iron slag and bog iron ore found at the archaeological site Virje – Volarski breg and surrounding area, which represent part of a broader data collection from archaeological sites with identified smelting activities during the late antiquity and early medieval period in the Podravina region (NE Croatia). At the Virje – Volarski breg site an early medieval iron smelting workshop was excavated in 2008. Remains of four bloomery furnaces had an in situ residue of iron slag formed during the smelting process (tap slag, furnace slag and furnace bottom slag). According to the archaeological record these furnaces were interpreted as free – standing slag – tapping bloomery furnaces. Samples for the analysis were selected according to the different types of iron slag originating from the same archaeological context, individual iron smelting furnaces i.e. individual smelts. The aim of the analyses was to define whether there are some distinctive patterns in chemical and mineralogical composition between samples of different types of iron slag formed during the smelting process, and in what way can these patterns be indicative for the study of the iron smelting processes in bloomery furnaces. X- ray powder diffraction (XRD) was used to determine mineralogical composition of slag and bog iron ore samples. Detail geochemical characterization of samples was performed using inductively coupled plasma mass spectroscopy (ICP-MS). Results of the mineralogical and geochemical analyses of slags are compared to results of bog iron ore samples found at the site in an archaeological context as well as with the samples of possible bog iron ore found in a geological survey of the broader study area of Podravina region

bloomery iron production ; bog iron ore ; early medieval period ; archaeometallurgy of iron ; ICP -MS ; XRD

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