Three isotopes of carbon are found in nature; carbon-12, carbon-13 and carbon-14.Carbon-12 accounts for ~99.8 % of all carbon atoms, carbon-13 accounts for ~1% of carbon atoms while ~1 in every 1 billion carbon atoms is carbon-14.A unique characteristic of 14C is that it is constantly formed in the atmosphere.
In the present study, the fractionation ratio b was determined by independent experiments on the chemical reduction of carbon dioxide (CO photosynthesis pathways.
In addition, the analysis of over 9600 full-sized OX-I and OX-II normalizing standards measured between 20 confirms b values lower than 2.0.
Scientists use a technique called radiometric dating to estimate the ages of rocks, fossils, and the earth.
Many people have been led to believe that radiometric dating methods have proved the earth to be billions of years old.
Hereafter these isotopes will be referred to as 12C, 13C, and 14C.
14C is radioactive and has a half-life of 5730 years.
A d13C value, then, represents the per mille (part per thousand) deviation from the PDB standard.
PDB refers to the Cretaceous belemnite formation at Peedee in South Carolina, USA.
Recall that atoms are the basic building blocks of matter.
Atoms are made up of much smaller particles called protons, neutrons, and electrons.
Fractionation during the geochemical transfer of carbon in nature produces variation in the equilibrium distribution of the isotopes of carbon (12C, 13C and 14C).