Final answer:
Volcanic ash is easy to date due to its unique chemical signature and the rapid cooling that locks in isotopic 'dates'.
Step-by-step explanation:
Due to its chemical composition, volcanic ash is easy to date. This is because volcanic materials, like volcanic ash, have a unique chemical signature that is consistent across an entire ash deposit from a specific eruption. Radiometric dating techniques, particularly those that measure the decay of radioactive isotopes like argon-40 to argon-39, are commonly applied to these materials to determine their age. Volcanic ash can blanket large areas and serve as a time marker for dating archaeological and geological layers.
This is crucial because volcanic ash layers allow scientists to correlate the timing of different events and infer connections between climate, geological, and archaeological records. Moreover, since volcanic ash undergoes rapid cooling, the minerals within the ash quickly lock in a 'date' of the eruption, which is essentially the time when the volcanic rock solidifies and its minerals start to retain radioactive elements used in isotopic dating.