Towards a benign burial environment : the chemistry of the burial environment.

The soil is a chemically, biologically and physically complex medium. There are an enormous number of variables that can influence the preserving/degrading nature of any soil and the burial environment it creates. Archaeological remains are recovered from all soil types. Most come from the moist aerobic soils that support plant life, however, particularly rich and informative assemblages come from dry arid soils and waterlogged deposits. The soil matrix is composed of; crushed rock and mineral particles, clay particles, organic material, water containing dissolved salts, gas and micro-organisms. It is a porous medium that rarely achieves equilibrium. Processes such as micro-organism activity, the weather, evaporation and ground water movements ensure that it is a state of constant change. In particular the cycles of wetting and drying, either through rising ground water or through surface water percolating down through the soil ensure that most soils containing archaeological remains have variable levels of water content, dissolved salts and oxygen