Which dating method is typically used to date items that are millions of years old?

Radiometric dating is the correct method used to date items that are millions of years old because it relies on the decay of radioactive isotopes within the materials being studied. These isotopes decay at a predictable rate, known as the half-life, allowing scientists to calculate the age of rocks and fossils that may span vast geological timescales. This technique is particularly valuable for dating igneous and some metamorphic rocks, which can be millions to billions of years old.

In contrast, stratigraphic dating focuses on the layering of rock formations to establish the relative ages of geological strata, rather than providing a specific age in years. Absolute dating, while it may sound similar to radiometric dating, generally refers to methods that provide an actual date or range of dates but may encompass various techniques that are not focused on radioactive decay. Relative dating, on the other hand, places events or objects in order without determining their exact numerical age, making it less suitable for dating older items.