Absolute ages are ages in years before present (e.g., This rock formed 100 milli
ID: 232885 • Letter: A
Question
Absolute ages are ages in years before present (e.g., This rock formed 100 million years ago (100 Ma)). Absolute ages are determined by studying the decay of unstable elements and knowing their half-lives. The table below summarizes characteristics of different unstable elements used to determine absolute geologic ages. What system, if any, can be used to determine the absolute age of dinosaur bones? Three students are debating how to date dinosaur bones. Student 1: We can use carbon-14 because it's used to date things that were once alive. The flesh of a dinosaur was composed of carbon. Student 2: But dinosaurs lived more than 65 million years ago, so carbon-14 doesn't work. To date something that old, you need to use potassium-argon or uranium-lead. Student 3: Carbon-14 can't date things as old as dinosaurs and potassium-argon and uranium-lead only work for volcanic rocks, so none of these works. With which student do you agree? Why?Explanation / Answer
1) The absolute age of dinosaur bones can be determined with the help of radiometric dating which uses isotopes like uranium-238, uranium-235 and potassium-40.
2) I agree with student 2 because he is right in saying that carbon-14 dating does not work , because it works upto last 50,000 years only.But dinosaur's bones are dated back to millions of years .
So as suggested by student 2 ,we need to use potassium -argon or uranium -lead methods.