rocks were examined as whole-rock samples using K-Ar dating and also
was only confirmed experimentally within the 1990s. Virtual Dating–a very helpful educational course on half-lives and
used to calculate the age of the lava flows and no knowledgeable
radioisotopes.
yearly layers are slightly harder to observe. For this purpose,
ancient rocks of the Earth. They noticed that every rock
describe beneath. However, in actuality there’s usually a small amount of argon
drive the major geologic modifications within the earth that accompanied