concept

Diagenesis

All the physical and chemical change that sediment - and anything buried in it - undergoes after burial, at low temperature and pressure, short of true metamorphism. This is the stage that decides the fate of a body that did get buried in time: pore water can fill its cavities with mineral and hold the structure, or dissolve its bone mineral and leave nothing at all. The same body, buried at the same speed, in two different pore-water chemistries, gives two opposite outcomes.