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The idea is the level of C14 in the atmosphere is constant, and living organisms will have about about the same ratio of C14 to C12. When they die they no longe
by cpburns2009 8y ago
The idea is the level of C14 in the atmosphere is constant, and living organisms will have about about the same ratio of C14 to C12. When they die they no longer replenish the C14 so the amount decreases over time as it decays (it's radioactive). You can then calculate how old something is based on the ratio of remaining C14 to C12. I'm not sure what the process is that relates C14 to stalagmite because it's inorganic.
- zeotroph 8y agoAnd all the CO2 which is added to the atmosphere by burning ancient and practically C14-free carbon compounds makes using this isotope less reliable, so other measuring methods are required.
- nitrogen 8y agoThe article says they used thorium-230 dating to calibrate layered samples from the stalagmites. This cave was special because the stalagmites did not contain much carbon from limestone, but did include atmospheric carbon.