Where does the extra dirt come from that buries an ancient civilization?

Question

I’m laying awake, not able to figure this out.

If our civilization were to be left untouched for thousands of years then over time it’d get covered in dirt. Some future generation would have to “dig up” our civilization in the same way we dig up artifacts from the ancient past.

Where does that dirt come from? Is it floating around in the atmosphere? Or does it get created somehow (ie. organic matter decomposing)?

My understanding is that older artifacts are buried deeper, which may not be the correct understanding. But is there some relationship to dirt vs time?

So many questions.

In: 18

Answer 1

Over hundreds of years, rocks break down into tiny grains, and these small grains, mixed with plant and animal matter — decayed roots, leaves, dead bugs and worms, and other organic matter thrown in, along with water and air — is what we call dirt or soil.

Sediment from flooding (before dams were common floods were more common) covers the land with dirt from time to time.