The Suitcase Lady

Sandy

July 18, 2017, 9:10 pm

Say the word “sand” and most of us think of beaches, deserts or sandboxes. We don’t think of the word “scarce”. So I was surprised to come across a New Yorker article entitled, “The End of Sand”.

Living on top of a sandbox with a beach at the end of the yard, I thought I was fairly well versed about these teensy, tiny rocks. It appears I have much to learn.

For example, geologists define sand not by composition, but by size, the grains being between 0.0625  and 2 millimeters across. Next above it on the scale is gravel and below it is silt.

Sand is mostly quartz, the commonest form of silica, but ocean sand will have lots of shell pieces mixed in. The White Sands in New Mexico are gypsum and black sands are from volcanic rocks.

Rocks go through a rock cycle (the universe being crazy for circles) and one geologist notes that “perhaps half of all sand grains have been through six cycles in the mill, liberated, buried, exposed and liberated again”. We do live on a geologically active planet or, as I explain to my younger students, earth really does rock and roll.

According to National Geographic, deserts cover more than one fifth of Earth’s land. However, the majority of these deserts are not sand. Only about 10 to 20 per cent of deserts are sandy. The rest are made of gravels, boulders and various soils such as clay.

Now for the real surprise. As improbable as it sounds, the planet, or more correctly, the human species, is running out of sand. According to a United Nations report, “sand and gravel (aggregates) are the largest volume of raw material used on earth after water. Formed by erosive processes over thousands of years, they are now being extracted at a rate far greater than their renewal.”

How can this be possible?  An American Geological Society report states that the typical American house requires a hundred tons of  sand, gravel and crushed stone for the basement, garage and driveway, and more than two hundred tons if you include the street that runs in front of it. A mile long section of a single lane of an American interstate highway requires 38,000 tons. And we aren’t the only ones on the planet who are digging and dredging. China hopes to complete 165,000 miles of new roads by 2030…..that’s three and a half times the  length of our Interstates.

There is a conclusion to be reached here: go to the beach before it gets turned into a skyscraper, interstate, computer chip, fracking fill or artificial dune in front of some threatened oceanfront McMansion.

Magnified grains of sand.

Magnified grains of sand – Source http://sandgrains.com

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