Fossil formation

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Taphonomy is the study of what happens to an organism after its recent death and before it becomes a fossil. Diagenesis is what happens thereafter to turn what remains of the body into something that will withstand the passage of time.(walking dinosaur costume)

 

The fossils that we pick up from the rocks, or rhat we see in museums, have changed a great deal in substance and appearance since they were parts of living organisms.

 

Fossil formation

The fossil is formed at the same rime as the sediment in which the organism lies is turned to sedimentary rock. This diagenesis usually involves two processes – compression and cementation. Compression is produced by the sheer weight of the overlying sediments, and acts to compact the grains of the sediment into a more coherent mass. In cementation,the ground water percolating through the rock deposits mineral, often calcite (the same as builders’ cement), between the grains gluing them together as a solid mass. Further compaction and the input of heat from the Earth s interior may alter the mineral content of the rock. If this happens it will take the rcxrk from the realms of a sedimentary rock to a metamorphic rock, a new type in which usually all the fossils are destroyed.(animatronic dinosaur)
In the rare occurrences in which an embedded organism becomes a fossil in a sedimentary rock, one of a number of different processes may be involved. An organism, or part of an organism, may remain unaltered. This is a very rare form of fossilization, but we sometimes see it in an insect preserved in a piece of amber. The procedure is simple. An insect settles on a glob of resin seeping from a tree and becomes trapped. It is engulfed and preserved before it has a chance to decay. Later the resin becomes buried and turned into amber through the normal processes that turn sediment to rock, and the insect is preserved within. Sometimes, though, this perfect preservation is illusory for the insects innards may have decayed through the action of its own bacteria. There are no dinosaur fossils that have been preserved like this, and no dinosaur blood in preserved mosquito stomachs.