ConcepTest: Oldest Rock Dating #1
This material was originally created for
Starting Point:Introductory Geology and is replicated here as part of the SERC Pedagogic Service.
Initial Publication Date: May 8, 2006
Question:
The world's oldest known rock is approximately 4 billion (4,000 million) years old. What are the approximate relative percentages of parent and daughter isotopes for Uranium-238 and Lead-206 (half-life = 4.5 billion years)?
a. 75% parent & 25% daughter
b. 45% parent & 55% daughter
c. 55% parent & 45% daughter
d. 25% parent & 75% daughter
a. 75% parent & 25% daughter
b. 45% parent & 55% daughter
c. 55% parent & 45% daughter
d. 25% parent & 75% daughter
Student Responses:
No data yet. The correct response is d.
If you would like to help acquire more Before and After statistics for this example, please contact the authors (see link at top of page).