How does absolute age differ from relative age?

1 Answer
Dec 5, 2015

One has an explicit date and the other is relative


Click here to see my response to this question regarding the dating of fossils

In short, absolute dating is a technique by which isotopes of a certain element are measured and then using a particular decay system (for example, #U-Pb#) an age can be constructed. This will give you a number and then you would calculate an associated uncertainty. For example, I may date a zircon mineral by measuring U and Pb and get an age of 2013 #+-# 15 Ma ( Ma = million years ago).

If I were to date something relatively I would have an idea of the sequence of geological events but no idea how long ago they look place. I could say what came first and second and third and so on but I would have no idea whether this all happen 10 minutes ago or 4 billion years ago!