Mossbauer effect (ME) spectroscopy is applied to the study of the mechanism of fossilization process and the effect of environmental conditions on plant and animal fossils. The samples are collected near the Mediterranean Sea in Egypt and Libya. The results indicate that fossilization takes place in two stages: (i) an iron mineral is formed which differs according to the geological conditions under which the fossil was formed; (ii) these minerals are then transformed to alpha -Fe₂O₃. The existence of the iron in trivalent state in all the iron minerals and the absence of sulphides indicate that fossilization took place under oxidizing conditions.