Abstract
This final installment of the three-part series examines U-Th/He and fission-track dating, so-called thermochronometric methods that provide cooling times from which uplift and erosion chronologies can be constructed. Also discussed is a range of methods based on the decay of cosmogenically produced isotopes such as 10Be, 14C, 26Al, and 36Cl that provide insight into the ages of sediments, glaciers, organic materials, and erosion surfaces. The article concludes with a brief reflection on the theological implications of an Earth that is billions of years old.