How can you find the age of a layer of rock that is surrounded by layers of volcanic ash

Radiometric dating method

Explanation:

The radiometric dating method is usually defined as a technique that is commonly used by the geologists in order to determine the age of the rocks based on the presence of radioactive elements or substances. These radioactive elements are comprised of unstable radioactive isotopes that release harmful radiations as it alters from an unstable condition to a stable one. They undergo decay at a definite rate which is known as the decay rate. For different rocks, this rate of decay is different.

The age of the rock layers can be determined by dating the rocks forming the layers. This will give a somewhat approximate age of the rocks.