About the blog: What Things Are Made Of
AMERICA'S GLOBAL DEPENDENCY FOR NEARLY EVERYTHING
Tuesday, January 19, 2010
Big vs. Little
Countries like the US, Russia, China, Canada, Brazil, and Australia are relatively rich in a wide variety of mineral resources for a simple reason: they’re big. Big enough to have a lot of geology, a lot of environments, a lot of situations where economic mineral deposits can accumulate.
Small countries just don’t have the geologic diversity to be rich in lots of minerals—but lucky geologic accidents do occur, sometimes making a small country the world leader in one or two commodities.
For example, Spain and Italy together account for two-thirds of the world’s reserve base of mercury. Spain’s mercury mines were among the oldest mines of any type in continual operation (since Roman times) when they ceased mining in 2003 because of decreasing demand for mercury. Pumice, a volcanic rock used in building-block construction, spews from volcanoes all over the world, but Greece produces more commercial pumice than any other nation. Finland produces more than a third of the world’s peat. The US imports nearly a million tons of peat annually for horticulture, but next-door Canada is the main supplier rather than Finland.
Botswana’s miners find more gem diamonds than miners elsewhere, at 25 million carats per year, but Russia is a close second with 23 million per year. Botswana and adjacent parts of southern Africa harbor a disproportionate number of kimberlite pipes, unusual igneous rocks that transport diamonds from depths of 150 to 200 km beneath the surface—depths where pressures are great enough to squeeze carbon into diamonds.
Boron—used in glass, ceramics, soap, detergent, bleach, enamel, and other everyday products—comes from many countries (and the US is a net exporter), but the world leader is Turkey. In western Turkey’s Menderes Massif unusual concentrations of tourmaline, a boron mineral that sometimes makes gemstones, give thermal waters their remarkable boron content. Recent faulting seems to provide pathways for the hot water, which serves as a geothermal resource as well as a reservoir for boron.
Gem tourmaline photo from Wikipedia under GNU Free Documentation License.