Phosphate analysis

Decay of animal organic matter leaves a residue of phosphates which is only slowly washed out of the deposit by percolating water. Careful chemical analysis can therefore reveal the former presence of such matter. It has been employed particularly in the study of cave deposits (to show human or animal occupation), settlement sites (to identify the uses to which different areas were put) and burials (to show the former existence of bodies completely decayed away). However, it can be easily affected by later use of the area, particularly fertilising. Saxon pits at the Lake End Road West site in Dorney were analysed for their phosphate content. Some were very high, suggesting their use as cess-pits.