Now, this technique is pretty cool if you want to calculate the age of a tree, for example, or even an Ancient Egyptian king a few thousand years young. Accurate dating of samples requires that the parent radioactive isotope has a long enough half-life such that it will still be quantifiable today.
New dinosaur dating technique paper released
So, what are our options? Since there is insufficient uranium present in dinosaur bones to date directly, scientists go for igneous rock rock formed from magma — usually in the form of a mineral called zircon ZrSiO 4.
Zircon is ideal because:. Once the absolute age of a piece of zircon has been determined, it is matched to the sedimentary layers that it was found in. Dinosaur bones that are found in the same layer can then be dated based on this with a certain degree of accuracy.
Rock face showing the layers that have slowly been deposited over many years. Now, some of you might be asking: In terms of charge, they are identical, meaning that they have the same chemical properties. However, mass spectrometry MS can be employed to exploit their differences in mass. There exist many different variations of mass spectrometry, but they work by a similar principle.
The sample is first vaporized turned into gas and ionized turned into positively charged ions , then accelerated along the length of a tube. Mass analyzers placed at the end of the tube are able to detect these, hopefully with enough sensitivity to tell the isotopes apart. This errorchron age is younger and less precise than the Fassett et al.
Which Radioisotope to Choose?
The difference between the two estimates of common Pb causes an appreciable bias in the ages reported by Fassett et al. No convincing biostratigraphic data establish a Paleocene age for this bone Lucas et al.
Fassett , p. Given the importance of accurate and precise age determinations for assigning a Paleocene age to dinosaur bones, we contend that there should have been a more rigorous validation of the dating methods and verification of ages from additional samples beyond those presented by Fassett et al.
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