A basaltic lava flow contains fragments of sedimentary rocks. Which of the following statements is true regarding their relative ages?
A)The lava flow is younger than the sedimentary rock.
B)The lava flow is older than the sedimentaryrock.
C)The lava flow and the sedimentary rock are the same age.
D)More information would be needed to determine their relative ages.

Question

Quizplus · Accepted Answer

The presence of sedimentary rock fragments within the lava flow indicates that the lava was erupted onto the surface after the sedimentary rock was deposited and had time to be eroded and broken up. Therefore, the lava flow is younger than the sedimentary rock.

A Basaltic Lava Flow Contains Fragments of Sedimentary Rocks