Radiometric dating . See Concept 25.2 (Page) View Available Hint(s)for Part A allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata only works on rocks younger than 75,000 years allows us to determine an absolute, errorless date relies on the fact that the daughter isotope decays to the parent isotope at a constant rate can be used to directly date fossils in sedimentary rock