My wife asked me the other day “Why is there more sand here after the river floods?”. I explained that because it was a mountain river, the flooding caused more rocks to grind together and tumble down from the hills grinding themselves eventually into fine sand.
In my article Reprint – A Grain of Beach Sand – Photography Book by Gary Greenberg I showed photos of grains of sand, some formed from stones, shells, etc.
A more detailed explanation of the source of sand and why it is different colours I found in this article from the Live Science website called:
Credit: Beach photo via Shutterstock
Summer wouldn’t be complete without a trip to the sandy shores of an ocean, bay, lake or river. As the gritty stuff gets in between your toes, you may wonder why beaches are distinctive sandy stretches and why sand looks and feels the way it does.
And then again, you might not — you didn’t come to the beach to think, did you? But for those in an asking mood, a sandy beach is essentially where pulverized, weathered rock along with some fragments of shelled creatures and other biota have collected, tossed up by the waves and as sediment from inland areas. More . . .