Therefore, mafic rocks and minerals often contain less potassium than an equal amount of silicic rock or mineral.
Potassium can be mobilized into or out of a rock or mineral through alteration processes.
An hourglass is a helpful analogy to explain how geologists calculate the ages of rocks.
When we look at sand in an hourglass, we can estimate how much time has passed based on the amount of sand that has fallen to the bottom.
But there are some questions that come to mind: Calculus students typically meet this problem somewhere in the second semester.
If the mineral contained 1 part per million Parentium-123 and 3 parts per million Daughterium-123, we could be sure all the Daughterium-123 was originally Parentium-123.
In other words there was originally 4 parts per million Parentium-123 and 0 parts per million Daughterium-123.
Most people think that radioactive dating has proven the earth is billions of years old.
Yet this view is based on a misunderstanding of how radiometric dating works.