Volume susceptibility graph for core 7, Mound D. As in core 2, there is at least one strong peak in undifferentiated mound fill. Interestingly, both the pre-mound surface and the top of the first mound stage have very low susceptibility values. These low values are likely a result of natural weathering processes (leaching of organics), although the intensity of occupation (less contribution of magnetic material on the surface or perhaps reduced burning) and the actual mound fill itself, which may contain weaker magnetic minerals than those found later, could also explain these lower values.