Contaminated carbon dating

Items such as limestone and plant roots can be considered naturally occurring contaminates because they will introduce new radiocarbon on the bones.An example of artificial contaminates are paper and animal glue in labeling a bone.Then when someone comes along and uses the tree for construction purposes or decoration, archaeologist misjudge the age of the site because the woods carbon dating will be older than when the person actually cut down the tree.I can imagine that this causes many problems for archaeologist because now whenever analyzing wood for its date, one must be skeptical as to if it will give information that is actually helpful for dating.Suess explained the phenomenon by the fact that the increased industrial use of fossil carbon in coal and in oil changed the ratio between the dead carbon C12 and the C14 (radiocarbon) in the atmosphere and therefore also in the biosphere.In centuries to come a body of a man or animal who lived and died in the 20th century would appear paradoxically of greater age since death than the body of a man or animal of the 19th century, and if the process of industrial use of fossil, therefore dead, carbon continues to increase, as it is expected will be the case, the paradox will continue into the forthcoming centuries.But as the method was refined, it started to show rather regular anomalies.

However, three or four rings formed in one year is not uncommon, especially if the tree grows on a slope, with the ground several times in a year turning wet and dry because of rapid outflow of water (Glueck et al., Botanical Review, 7, 649-713; and 21, 245-365).These items will also bring in new radiocarbon to the bone.Both of these contaminates, natural and artificial, will make the bones carbon dating much younger than it actually is.The correctness of the method depends greatly on the condition that in the last 40 or 50 thousand years the quantity of water in the hydrosphere (and carbon diluted in it) has not substantially changed. The method depends also on the condition that during the same period of time the influx of cosmic rays or energy particles coming from the stars and the sun has not suffered substantial variations.To check on the method before applying it on various historical and paleontological material, Libby chose material of Egyptian archaeology, under the assumption that no other historical material from over 2,000 years ago is so secure as to its absolute dating.

Leave a Reply