An analysis of Indigenous earth mounds on the Calperum Floodplain, Riverland, South Australia

This paper provides new data on Indigenous earth (oven) mounds in the Murray Darling Basin (MDB) via an analysis of these features on the Calperum Station floodplain in South Australia’s Riverland region. Our analysis of earth mound dimensions, attributes, placement, elevation and relationships to other mounds and site types reveals the following: 1) That Calperum earth mounds lie within the temporal, dimensional, morphological and functional dataset for earth mounds which occur in similar riverine environments within the MDB; 2) That Calperum oven mounds share similarities with the ashy deposits of the Menindee Lakes region but demonstrate a higher and more contained structure; and 3) The archaeological record on the Calperum floodplain, including the location, distribution and surface content of earth mounds and occupation sites, suggests an intimate causal relationship with the local geomorphology. We argue that this has influenced the placement of oven mounds and the adoption of a system of active management of aquatic plant resources to mitigate risk, and to maximise outcomes over the annual subsistence cycle. Via comparison of the temporal ranges for other similar mounds in other regions of the MDB, we postulate that the mounds surveyed were likely created in the late Holocene. The data indicates that the earth mounds which occur on the floodplains of active riverine environments and/or seasonal floodplains within the MDB, date consistently to less than 3000 years old, whilst geomorphologically stable environments contain some mounds which are considerably older. We did not find evidence for the development and use of any Calperum oven mounds as occupational space, nor evidence for the co-location of living space and intensive oven mound cooking functions as outlined by Westell and Wood (2014) for the lower Murray Gorge.