Example of absolute dating geology
Chart of a few different isotope half lifes: In reality, geologists tend to mix and match relative and absolute age dates to piece together a geologic history.
The atoms of some chemical elements have different forms, called isotopes.
These break down over time in a process scientists call radioactive decay.
Relative age dating also means paying attention to crosscutting relationships.
Say for example that a volcanic dike, or a fault, cuts across several sedimentary layers, or maybe through another volcanic rock type.
In a way this field, called geochronology, is some of the purest detective work earth scientists do.
There are two basic approaches: relative age dating, and absolute age dating.
Pretty obvious that the dike came after the rocks it cuts through, right?
With absolute age dating, you get a real age in actual years.
Geologists often need to know the age of material that they find.