Which dating method is used specifically to date volcanic rock or ash deposits?

Radiopotassium dating is a technique specifically designed to date volcanic rock and ash deposits. This method relies on the decay of potassium-40 (a radioactive isotope of potassium) into argon-40 over time. Because volcanic eruptions can release large amounts of materials that encapsulate potassium from the surrounding environment, this dating method is particularly effective for dating events that happened in geological time, often ranging from thousands to billions of years.

When volcanic material solidifies, any argon-40 gas trapped in the rock escapes, and as time progresses, potassium-40 decays into argon-40 at a known rate. By measuring the ratio of potassium-40 to argon-40 in a sample of volcanic rock or ash, scientists can determine the time since the rock solidified, thus providing a reliable date for volcanic events.

In contrast, traditional radiocarbon dating and AMS (Accelerator Mass Spectrometry) radiocarbon dating are primarily used for organic materials, typically dated up to about 50,000 years old, making them unsuitable for volcanic rock. Thermoluminescence dating is used for dating minerals and sediments but is not specific to volcanic materials. This distinguishes radiopotassium dating as the appropriate method for dating volcanic rock and ash deposits