These tests have consistently given the same ages for each of these objects.
Examples of a number of consistent dates derived from different methods are given.
A short but clear explanation about radioactive isotopes commonly used for determining ages of rocks (with graphics) and putting numbers on the geologic time scale, extending it back before the occurance of abundant index fossils.
This is a relatively new method intended to to improve the precision of uranium and thorium istopy methods.
He concluded, after studying rocks at many outcrops, that each layer represented a specific interval of geologic time.It excludes contamination and weathering of travertines and makes possible more precise dating of thin deposits of secondary carbonates.No web-based resource for this method is available.Many of these links also appear where appropriate below.James Hutton and William Smith advanced the concept of geologic time and strengthened the belief in an ancient world.