Fossi

Fossils occur commonly around the world although just a small proportion of life makes it into the fossil record. Most living organisms simply decay without trace after death as natural processes recycle their soft tissues and even hard parts such as bone and shell. Thus, the abundance of fossils in the geological record reflects the frequency of favourable conditions where preservation is possible, the immense number of organisms that have lived, and the vast length of time over which the rocks have accumulated.

The term ‘fossilisation’ refers to a variety of often complex processes that enable the preservation of organic remains within the geological record. It frequently includes the following conditions: rapid and permanent burial/entombment – protecting the specimen from environmental or biological disturbance; oxygen deprivation – limiting the extent of decay and also biological activity/scavenging; continued sediment accumulation as opposed to an eroding surface – ensuring the organism remains buried in the long-term; and the absence of excessive heating or compression which might otherwise destroy it.