We present a series of soft sediment geological phantoms constructed to simulate volcanic ash deposits preserved within sediment cores. This study aimed to systematically discern which sediment components are most effectively detected and therefore characterised by X-ray microCT (μCT). Samples with low or overlapping attenuation contrast but distinct morphologies such as coarse grained (>125 μm) ash within fine mud (<4 μm) can be manually separated using analysis software, while samples with high attenuation contrast display distinct horizons that are easily segmented using attenuation thresholds. We anticipate that this work will have broader applications within Earth Science to optimise the exploration of sediment with μCT analysis.