How It Is Preserved
Normally, organic carbon is decayed before it is rotted. Anoxia can prevent decay, but the prevalence of bioturbation associated with body fossils indicates that many BS sites were oxygenated when the fossils were deposited. It seems that the reduced permeability associated with the clay particles that make up the sediment restricted oxygen flow; furthermore, some beds may have been 'sealed' by the deposition of a carbonate cement.
The carbon isn't preserved in its original state, which is often chitin or collagen. Rather, it is kerogenized. This process seems to involve the incorporation of aliphatic lipid molecules.
Read more about this topic: Burgess Shale Type Preservation
Famous quotes containing the word preserved:
“Semantically, taste is rich and confusing, its etymology as odd and interesting as that of “style.” But while style—deriving from the stylus or pointed rod which Roman scribes used to make marks on wax tablets—suggests activity, taste is more passive.... Etymologically, the word we use derives from the Old French, meaning touch or feel, a sense that is preserved in the current Italian word for a keyboard, tastiera.”
—Stephen Bayley, British historian, art critic. “Taste: The Story of an Idea,” Taste: The Secret Meaning of Things, Random House (1991)