The reality of our biosphere is that virtually everything is permeated with microbes and their products. These plastic-like coatings are produced by bacteria and fungi. Sure enough, microscopic examination of a few linen fibers from the Shroud of Turin show that they, too, are coated with such varnishes. These biogenic varnishes may introduce carbon that has been recently fixed from the atmosphere and thus make the sample's age appear younger than it really is. More than the Shroud is at stake here.
Bacteria contaminate just about everything, including wood and bone from archeological sites.
The importance of this phenomenon is still unclear. Cross reference . William R. Corliss Other Sites of Interest SIS . Catastrophism, archaeoastronomy, ancient history, mythology and astronomy. Free resource for people thinking about working at home.