Simplify the following text for a Grade 14 native English-speaking person.
Original: The stratigraphy is extremely deep and layers of volcanic ash and stones allow radiometric dating of the embedded artifacts , mostly through potassiumâ `` argon dating and argonâ `` argon dating .
Simplified: The stratigraphy is extremely deep and layers of volcanic ash and stones allow radiometric dating of the embedded artifacts , mostly through potassium-argon dating and Argonâ `` argon dating .