ste
XX XX
X X X X
x
++
X X X
X
X
Figure A.
++
8. What type of unconformity is D?
+
^ ^
X
X
t
10. What is the half-life of the isotope in Question 9?
++
KAXX
tr
t
11. Give an indirect numerical age of the rock unit above D.
المال
t
XX
xxx
9. The rock unit below D was dated at 60 million years old. The rock contained 50% parent atoms and 50%
daughter atoms. How many half-lives have passed?
-D