Beach sand arises from an age-long journey of eroded mountain sediments transferred by rivers, providing hints about their origin and journey based on their color and shape. Nevertheless, human activities, especially dam building, have actually disrupted this cycle, trapping significant quantities of sand and causing worldwide shoreline disintegration.
Where Does Beach Sand Come From?
The seemingly simple beach sand is in fact the result of an impressive natural process of mountain erosion and river transport. As mountains wear down, they produce sediments including mud, sand, gravel, cobbles, and boulders, which then take a trip via rivers and streams to the sea, getting ground down along the method.
Theres more to beach sand than satisfies the eye. It has stories to inform about the land, and a legendary journey to the sea. Thats since mountains end their lives as sand on beaches.
Over time, mountains deteriorate. The mud, sand, gravel, patches, and boulders they shed are washed into streams, which come together to form rivers. As they flow down to the sea, all this sediment is ground up and used down in natures version of a rock tumbler.
By David R. Montgomery, University of Washington
June 26, 2023
Thats because mountains end their lives as sand on beaches.
Next time youre at the beach, choose up a handful of sand and look closely at it. The beach is just a momentary stop for sand. Keeping a beach nurtured with sand is essential for keeping it sandy.
All in all, human activity has cut off about half the sand that would otherwise end up on the worlds beaches.
Big rocks break down into smaller pieces, so the majority of what reaches the sea is mud. These silt and clay particles are too small to perceive with the naked eye. You can see private grains of sand, which are simply larger bits of rock.
Next time youre at the beach, pick up a handful of sand and look carefully at it. Are all the grains the same color, or a rainbow assortment? Are they jagged and angular, or smooth and round?
This started as a range of mountains.
Different colors of sand originated from various minerals, like khaki feldspar, smoky white quartz, green olivine, or black basalt. The mix of colors in beach sand tells you what sort of rocks produced it.
The shape of sand grains also supplies hints about where they originate from. Angular grains of the exact same kind of sand have actually not taken a trip as far as smooth round grains, which have been more worn down. And weak rocks break down to mud faster than acid rocks, so sand tends to be made from the harder types that break down gradually.
About a tenth of the supply of sediment that reaches the sea is sand. These particles are in between about half a millimeter and 2 millimeters in size– approximately as thick as a cent. These particles are big enough that they dont flow right out to the deep sea.
The beach is simply a short-lived stop for sand. Huge waves pull it offshore, and smaller waves press it along the coast. So keeping a beach nurtured with sand is important for keeping it sandy.
Many beach towns spend millions of dollars to rebuild eroded beaches with new sand.
Today lots of beaches are starving. Lots of dams trap the sand that streams down rivers, stacking it up in reservoirs. All in all, human activity has actually cut off about half the sand that would otherwise wind up on the worlds beaches.
Humans havent turned the waves off, so as beach sand washes away and isnt replenished, the shoreline deteriorates. That indicates that many beaches all over the world are diminishing, gradually but definitely.
So next time you dig your toes into beach sand think about the impressive journey it took to get here underneath your feet. Take a minute to consider where the sand originated from and where its going.
Written by David R. Montgomery, Professor of Earth and Space Sciences, University of Washington.
Adjusted from a post initially released in The Conversation.