The study of clay-built bloomery furnace shafts in Sweden – Ceramological analyses of an important part of iron production through 1500 years. (February 2023)

• Record Type: Journal Article
• Authors: Stilborg, Ole
• Is Part Of: Journal of archaeological science. Volume 47(2023)
• Publication Date: 2023-02
• Subjects: Clay -- Temper -- Bloomery furnace -- Thermal gradient -- Vitrification -- Repair; Archaeology -- Periodicals; Archaeology -- Research -- Periodicals; 930.1
• DOI: 10.1016/j.jasrep.2022.103808
• Languages: English
• ISSNs: 2352-409X

Abstract

Highlights: Overview of archaeometric research of technical ceramics connected to iron making in prehistoric-Medieval Sweden. Data collected through ceramological study of furnace walls (multiple methods). The geographical spread of variable raw material choices and mixtures. A potentially rich source of data for the understanding of the organisation of iron making. Open data in database SEAD under construction. Abstract: The study of the clay-built shafts for bloomery furnaces in Sweden from the Iron Age through to the Medieval period and even later in parts of the country has been evolving over the last 25 years in a tight collaboration between ceramologists (from Lund University at first (KFL) and later company SKEA) and archaeometallurgists at the company "The Archaeologists" in Uppsala (formerly the Geoarchaeological Lab, GAL). This article (financed by the database-project VISEAD) presents an overview of the results from a geographical and chronological perspective with an outlook to European research. It claims the existence of craft traditions primarily in raw material choices and treatment as well as in the curation of the shafts as an indispensable part of the iron production strategy. There is no clearly visible chronological development but some regional differences although the broader traditions are spread over larger areas. Major traditions concern furnace shafts with a wickerwork frame or with a stone frame and one tradition that only used naturally coarse clays while another added organic temper – all four with different geographical spread. Besides these major traditions deviant technical solutions have been observed involving fx. temper of crushed rock, hair or iron ore. Much of the variation seems to come down to differences in the skill and experience in the builders of the shaft. This varied picture may reflect different organizations of the craft including both locally developed knowledge and ambulant expertise.