They must find rocks that contain these parent radioisotopes, even if they are only present in minute amounts.
Most often, this is a rock body, or unit, which has formed from the cooling of molten rock material (called magma).
Examples are granites (formed by cooling under the ground) and basalts (formed by cooling of lava flows at the earth’s surface).
The next step is to measure the amounts of the parent and daughter isotopes in a sample of the rock unit.
Most people today think that geologists have proven the earth and its rocks to be billions of years old by their use of the radioactive dating methods. Given so much time, the ‘impossible’ becomes possible, the possible probable, and the probable virtually certain.
Ages of many millions of years for rocks and fossils are glibly presented as fact in many textbooks, the popular media, and museums. One has only to wait: time itself performs the miracles.”1 Yet few people seem to know how these radiometric dating methods work.
So, for example, every carbon atom contains six protons and six electrons, but the number of neutrons in each nucleus can be six, seven, or even eight.
The atoms in each chemical element may vary slightly in the numbers of neutrons within their nuclei.
These slightly different atoms of the same chemical element are called isotopes of that element.
Thus it appears that God probably created those elements when He made the original earth.
Geologists must first choose a suitable rock unit for dating.
Thus, the parent isotopes that decay are called radioisotopes.