Clocks in the rocks radioactive dating method
Determining the age of a rock is a two-step process.
In some lakes or bays where underwater sedimentation occurs at a relatively rapid rate, the sediments have seasonal patterns, so each year produces a distinct layer.
These atomic clocks slow down very slightly only a second or so per year as predicted by Einstein's theory of relativity.
Its great advantage is that most rocks contain potassium, usually locked up in feldspars, clays and amphiboles.
The text by Dalrymple is meant to be relatively easy to read, but is also very comprehensive.
The scheme has a range of several hundred thousand years.
However, in reality there is often a small amount of argon remaining in a rock when it hardens.
The main limitation is that it only works on certain igneous rocks as most rocks have insufficient Re and Os or lack evolution of the isotopes.
These isotope ratios are sensitive to the temperature at the time they fell as snow from the clouds.
Many different radioactive isotopes and techniques are used for dating.
Radiometric dating of rocks also tells how much time has passed since some event occurred.
Comparison of uranium ages with ages obtained by counting annual growth bands of corals proves that the technique is.