Carbon dating live snail
Marine organisms and those who consume them take in carbon 14 from the exchange process of carbon 14 (in the form of carbon dioxide) in the atmosphere and the ocean or any body of water.However, carbon 14 content is not the same at the surface mixing layers and that in the deep ocean; hence, not all marine organisms have the same radiocarbon content.Studies show that equilibration of carbon dioxide (with carbon 14) in surface water is of the order of 10 years.The degree of equilibration of carbon dioxide in deep water remains unknown.Note: A negative Delta-R will make the date older (typically presuming freshwater dilution from the global marine average).Sample reports below show the difference between a radiocarbon date of 1000 /-30 BP with a Delta R of 0 /-0 (i.e.Snails from limestone areas produced variable anomalies of as much as 3,120 yr due to incorporation of C content even within species, no standard correction factor for limestone anomaly can be applied.However, dating error can be minimized by selecting ecologically appropriate species or by comparison of analyses of several fossil species, within a stratum, to their modern counterparts.
Carbon 14 is a naturally occurring isotope of the element carbon and is called radiocarbon. Another characteristic of carbon 14 is that it is continually being formed in the upper atmosphere as a product of the reaction between neutrons produced by cosmic rays and nitrogen atoms.
Samples from marine organisms like shells, whales, and seals appear much older.
Another factor to consider is that the magnitude of the marine reservoir effect is not the same in all locations.
global marine reservoir correction) is applied automatically for all marine carbonates.
This automatic correction means the radiocarbon date gets more recent in time due to the fact that it takes 200-500 years for present-day carbon dioxide in the atmosphere to be incorporated and distributed (equilibrated) through the ocean water column.