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

There is a known amount of space dust that reaches the surface of earth. It’s something like four inches every 100 years. In a million years, that’s 40,000 inches, over 3000 feet, sixty percent of a mile.