Molecular Sieve is Playing an Important Role in Redefining Contemporary Knowledge of Early Human History

Radioactive carbon dating was a technique developed by Willard Libby in 1949 (a discovery that won him the Nobel Prize in Chemistry over a decade later) that can be used to date carbon based materials up to 60,000 years.  This number is significant because it allows scientists to date all of civilized human history and even some early human history and the history of our common ancestors. Carbon dating can also be used to learn valuable things about what the environment and climate were like in the past, too.

Carbon dating works by measuring the isotopes carbon-14 and carbon-12 or 13 in any fossil.  When people, plants, or anything that is carbon based is alive, it is able to generate carbon-14, when it dies it stops generating carbon-14.

Carbon-14 decays though, while Carbon-12 and 13 do not decay.  Carbon-14 has a half life of 5,730 years, which means due to radioactive decay the amount of carbon-14 in an object will be half of what it was in 5,370 years.  Carbon-12 and 13 do not decay so the ratio of the decaying carbon-14 needs to be compared to carbon-12 or 13  to determine how old the object is.

However, recently studies have shown that samples that go through standard carbon dating tests have accuracy issues when the sample is older than 30,000 years.  This is due to 98% of the carbon-14 already having decayed and because carbon-14 molecules from surrounding soil or other carbon based items start to seep into the fossils.  This combination of events can throw off carbon dating by thousands of years.

Tom Higham, an archeologist working for the University of Oxford, is modifying the carbon dating process.  Tom has been using molecular sieve to remove extra C02 and other carbon chains that are contaminating samples and are distorting the test results.

The graphic below shows how some fossils in Europe have been re-dated using molecular sieve.

Note: 13X molecular sieve is frequently used to remove C02 and other large hydrocarbons from the air, and this is most likely the type of molecular sieve being used to improve fossil dating. 

Using molecular sieve in carbon dating has improved the dating of fossils and items over 30,000 years old.  The improvements in the accuracy of these tests could redetermine historical dates/events that are currently being contested; such as when the first humans entered Europe and whether humans came into contact with neanderthals.  As more carbon dating studies are conducted we may see contemporary knowledge of early human history be redefined.

Sources:

http://www.nature.com/news/archaeology-date-with-history-1.10573

http://planetearth.nerc.ac.uk/features/story.aspx?id=833

http://science.howstuffworks.com/environmental/earth/geology/carbon-142.htm