If the pink layer has an absolute age of 350 million years, which two of these statements must be true?

Question

afolded, wavy rock strata. From top to bottom, the strata are labeled Tan, Beige, Brown, Gray, Pink, Light green, and Khaki.

The khaki layer was formed after the pink layer

The light green layer is more than 350 million years old

The brown layer is also 350 million years old

The pink layer folded more than 350 million years ago

The tan layer is less than 350 million years old

Answer 1

Based on the information that the pink layer has an absolute age of 350 million years, we can analyze the implications for the other layers:

1. The khaki layer was formed after the pink layer: This statement must be true if the khaki layer is located above the pink layer because, in geological terms, layers that are on top are typically younger than those below them.

2. The light green layer is more than 350 million years old: This statement cannot be determined to be true because the light green layer could be older or younger than the pink layer depending on its position and the geological history.

3. The brown layer is also 350 million years old: This statement is not necessarily true, as the brown layer could be older or younger than the pink layer.

4. The pink layer folded more than 350 million years ago: This statement must be true, assuming that folding occurs after a layer has been deposited. Therefore, if the pink layer has been folded, that event would have to occur after its deposition, meaning it folded at some point after it formed.

5. The tan layer is less than 350 million years old: This statement must be true if the tan layer is above the pink layer, as geological layers above an older layer are typically younger.

Thus, the two statements that must be true are:

• The khaki layer was formed after the pink layer.
• The pink layer folded more than 350 million years ago.