Geophysical and archaeological investigations of Baker’s Flat, a nineteenth century historic Irish site in South Australia

The Irish settlement of Baker’s Flat, located in the rural heart of South Australia near the town of Kapunda, was occupied from the mid-nineteenth century for about 90 years. Although little archaeological work has been carried out in Australia specifically on Irish communities, Baker’s Flat is of particular interest because it potentially operated as a traditional Irish clachan, an informal clustering of farm dwellings and outbuildings, and home in this instance to the Irish immigrants who worked in the nearby copper mine. The site was cleared for farming purposes in the 1950s, and little recordation of the dwellings and settlement exist today, aside from a single 1890s map. Owing to the demolition and landscape modification, it was unclear whether any intact subsurface deposits still existed. Therefore, this site was ideal for deploying two geophysical methods, ground-penetrating radar (GPR) and magnetic gradiometry, to assess the presence of subsurface remains and explore the spatial layout of the site. Our results, when compared with those obtained from surface surveys and targeted archaeological excavation, revealed numerous subsurface features and helped to confirm that Baker’s Flat was built in the style of a traditional Irish clachan. This study also demonstrated that magnetic gradiometer was the better geophysical method for mapping this settlement as the nature of the geology (shallow bedrock) and construction of the houses (built within the bedrock) limited the utility of GPR.