Question

question 9 of 10
why are no rocks found that date from the first 800 million years of earths existence?

a. they have all been buried too deeply under newer rocks.

b. earth was too hot to have solid rocks at that time.

c. all the rocks from that time period have been destroyed by plate movements.

d. they were all destroyed by a comet impact.

Explanation:

To determine why no rocks from Earth's first 800 million years exist, we analyze each option:

• Option A: Burial under newer rocks wouldn't eliminate all old rocks; some should still be accessible. So A is incorrect.
• Option B: During Earth's early formation, it was extremely hot (molten state). Rocks require a solid environment to form and persist. Since Earth was too hot to have solid rocks initially, no rocks from that time could form or remain. This aligns with geological knowledge of Earth's early history (Hadean Eon, where Earth was molten).
• Option C: Plate movements started later, and the lack of early rocks is due to the molten state, not plate destruction. So C is incorrect.
• Option D: A single comet impact wouldn't destroy all rocks from 800 million years; the molten state is the primary reason. So D is incorrect.

Answer:

B. Earth was too hot to have solid rocks at that time.