Diagenesis

Physical and chemical alteration after burial, potentially modifying fossil tissues and isotopic compositions.

Change in the crystal organization of fossil material during alteration, potentially obscuring original histological or chemical information.

precipitation or replacement by minerals during burial alteration. Early mineral formation can retain fine biological detail, while later alteration can destroy or obscure it.

Reduction of sediment volume during burial that can flatten, distort or fracture enclosed remains.

Preservation or replication by calcium phosphate minerals, sometimes retaining soft-tissue detail when precipitation occurs before its destruction.