Eli5 Where does the dirt come from?

Question

When looking at a geological timescale, typically ‘the deeper you dig, the older stuff gets’, right?
So, where does this buildup of new sediment come from?
I understand we’re talking about very large timeframes here, but I still dont really get it.

In: 19

Answer 1

When I took an archaeology 101 class in college, this question always kind of bothered me. Sure, it makes sense that deeper things are older, but where does all the new dirt come from? I’d think that the earth was a closed system and all the dirt has been here for eons and there’s no new dirt. But reading these explanations it kinda makes sense