How does iron preserving works?

I read how it probably works.

When a dino dies  its blood decomposes and releases iron from hemoglobine. When the iron spread through tissue and bone it initiated crosslinking. The soft tissue most affected by the crosslinking would be  preserved for a long period of time. Soft tissue that was crosslinked and sealed safely inside a hard bone, could survive for millions of years...until the present day.

http://www.sciencemag.org/news/2017/01/scientists-retrieve-80-million-year-old-dinosaur-protein-milestone-paper

The article refers to preservation of a protein. I.e. biomolecule, not tissue. In this case it depends on precipitation of the protein, though it is still not clear how that alone could preserve the proteins for the indicated amount of time.

Thx for the explanation.

Young earth creationists often use this to pretend that dinosaurs lived 6000 years ago and are not as old as science says they are.