EARTH NEEDS MORE GREEN SAND BEACHES!
Using Naturally Occurring Olivine to Sequester Carbon Emissions
Based on Nature News & Comment Nature 505, 464 (23 January 2014)
'Weathering’, or breaking down, of rocks is a hugely important but very slow part of the carbon cycle. Natural weathering locks up atmospheric carbon dioxide by means of chemical reactions between common silicate minerals and air.
For example, when magnesium-rich olivine, a rock of particular interest to geoengineers, is brought together with CO2 and water under natural conditions, the resulting reaction forms magnesium carbonate and silicic acid, thereby removing and storing carbon.
Some scientists think that this natural process could be exploited to offset at least some of the carbon emitted by human activities. Rather than waiting for rocks to be slowly weathered away, olivine could be mined on an industrial scale, ground up, and spread over land or in the sea, speeding up these chemical reactions and sucking vast quantities of CO2 out of the atmosphere.
NATURE ALREADY MAKES GROUND OLIVINE
One obvious way to try this is to do something nature already does. Make more green sand beaches! Scatter the crushed olivine on beaches everywhere …
There are now only four natural olivine-sand beaches.
- Papakolea Beach in Hawaii
- Talofofo Beach, Guam
- Punta Cormorant Beach in the Galapagos Islands
- Hornindalsvatnet in Norway, the deepest lake in Europe.
Green sand gets its name from the green glassy crystals of olivine that make up a significant part of it. The olivine in the sand on these beaches comes from olivine-rich lava, as seen in the partially weathered lava in the TOP IMAGE.
OLIVINE ‒ a/k/a PERIDOT
Olivine is the most abundant mineral in the Earth’s mantle, down to about 410 km below the surface. It is a common component of lava.
Lab experimentation has shown that under pressures found 360 km below the surface of the earth, olivine can absorb a great deal of water. Because olivine is so abundant, it may be that more water is dissolved in subsurface olivine than is contained in Earth’s oceans.
Olivine is a magnesium iron silicate with the formula (Mg+2, Fe+2)2 SiO4. Check out olivine in Wikipedia …
Photo of Hawaii’s Papakolea Beach by Shannon Lucas
Other images: Nature and Wikimedia