Chemical fractionation, as we have seen, calls radiometric dates into question. Before determining the age of the granite, it must be analyzed under a powerful microscope, and with an electron microprobe, to make sure that its original minerals have not been cracked and altered by metamorphism since the rock first formed. No matter what the geologic situation, these basic principles reliably yield a reconstructed history of the sequence of events, both depositional, erosional, deformational, and others, for the geology of a region. How long were these gaps?
Geologists analyze geologic time in two different ways: in terms of relative geologic age, and in terms of absolute or numeric geologic age. IN: Bergren, W. Geochronologists do not claim that radiometric dating is foolproof no scientific method is , but it does work reliably for most samples. He concluded, after studying rocks at many outcrops, that each layer represented a specific interval of geologic time. We were standing on the Simi Volcanic flow, about 80 miles south of the south end of Death Valley.