The age of the layer of rock can be determined through radiometric dating techniques. Radioactive isotopes (such as carbon-14 or uranium-238) within the rock can be measured to determine the time that has passed since the rock solidified. The volcanic ash layers surrounding the rock can also be dated using radiometric dating, providing a range of time within which the rock layer must have formed. By comparing the age of the rock with the surrounding volcanic ash layers, scientists can estimate the age of the rock layer with reasonable accuracy.
