Although relative ages can generally be established on a local scale, the events recorded in rocks from different locations can be integrated into a picture of regional or global scale only if their sequence in time is firmly established.
The time that has elapsed since certain minerals formed can now be determined because of the presence of a small amount of natural radioactive atoms in their...
Here is an easy-to understand analogy for your students: relative age dating is like saying that your grandfather is older than you.
What’s more, if the whole rock is badly weathered, it will be hard to find an intact mineral grain containing radioactive isotopes.
You might have noticed that many of the oldest age dates come from a mineral called zircon.
Precise isotopic ages are called absolute ages, since they date the timing of events not relative to each other but as the time elapsed between a rock-forming event and the present.
Absolute dating by means of uranium and lead isotopes has...
The narrower a range of time that an animal lived, the better it is as an index of a specific time.