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PeterSibley
10-05-2017, 04:12 PM
I was at the beach last week with beautiful white sand but it made me wonder why the sand grains aren't smaller? If the process that reduces material to sand why doesn't it continue until the sand grains are dust ?

Gerarddm
10-05-2017, 04:13 PM
And a parallel question: why do rocky beaches stay rocky?

Rum_Pirate
10-05-2017, 04:15 PM
They probably do reduce (both the sand and the rocks) but the time period will be quite a while and differ.

Peerie Maa
10-05-2017, 04:18 PM
I was at the beach last week with beautiful white sand but it made me wonder why the sand grains aren't smaller? If the process that reduces material to sand why doesn't it continue until the sand grains are dust ?

The action of the waves sort the beach material. Your dust is somewhere else.


Don Moxom, the Warden of the Fleet and Chesil Nature Reserve. He's based at the Chesil Beach Visitor Centre at Portland and thinks the beach's unique character is part of its appeal - but is also what could threaten its future.

Peas to potatoes
He says: "It's unique in so many ways - such as in its formation, when pebbles were washed up at the end of the last ice age.
"But it's not a spit of pebbles - the beach is literally one bar washed up from the sea and in the process of doing so the sea has graded the pebbles in size all the way along it."
"You get the pea sized pebble to the west, then the potato sized pebble here at Portland."

robm
10-05-2017, 04:19 PM
Perhaps the smaller grains are too small to remain on the beach. They get washed away, or filter down below the coarse surface material.

ron ll
10-05-2017, 04:24 PM
Maybe the size of beach sand is the minimum size that stays on the ground. Any smaller and they go airborne in a breeze.

P.I. Stazzer-Newt
10-05-2017, 04:25 PM
Different beaches have different sized grains.

Some places we have soft mud others sharp sand still others pebbles....

Peerie Maa
10-05-2017, 04:27 PM
Maybe the size of beach sand is the minimum size that stays on the ground. Any smaller and they go airborne in a breeze.

You have obviously never been on a sandy beach in a breeze. With enough wind you get
4268
dunes.

ron ll
10-05-2017, 04:33 PM
Yes, but still the minimum size grain that stays on the ground, even if temporarily airborne.

PeterSibley
10-05-2017, 04:41 PM
Perhaps the smaller grains are too small to remain on the beach. They get washed away, or filter down below the coarse surface material.

That seems most likely, the grain size on this beach is very uniform.