Archive Classic: Where Do Gems and Precious Metals Come From?
Reprinted from September 17, 2011
Gold, diamonds, and other precious metals and gems… they are found close to the surface of the earth where humans can mine them and make jewelry. But they shouldn’t be there. Heavy elements should have sunk deep into the core of the Earth soon after it was formed. Wait till you hear some of the latest ideas about how precious metals and gems arrived near the surface. Maybe they shot up from the mantle. Maybe they came from outer space.
The fact is, geologists and planetary scientists don’t really understand why we have rare precious stones so accessible for man. PhysOrg printed an article entitled, “Tackling mysteries about carbon, possible oil formation and more deep inside Earth.” It’s about the Deep Carbon Observatory project destined to answer fundamental questions about the Earth’s interior. Inside you will learn about how diamonds the size of potatoes shoot up from the mantle at 40 miles per hour, believe it or not. However it happens, it’s convenient for miners, who otherwise would have to dig really, really deep holes to supply the wedding ring market.
MSNBC posted an article about where gold comes from. “There’s gold in them thar meteorites!” the headline blazes. Jessica Marshall tells us, “Rocks pummeled Earth about 3.9 billion years ago, delivering precious metals.” Gold, platinum, iridium, nickel, and tungsten are attracted to iron and should have followed it into the molten Earth’s core, she explained. Meteorites to the rescue! They came from space. That’s right: “All the precious metals that we find today — and probably also water — have been introduced to the accessible Earth from these late-stage meteorites.” Maybe they even brought life! Figure that suggestion out after reading that the bombardment was probably “a terrible event for life” that “probably would have melted the planet, blown off any existing atmosphere.”
Marshall used the new theory to bolster an old idea called the Late Heavy Bombardment. She reported a new study about tungsten isotope measurements to support the idea of a swarm of big meteors hitting Earth and the moon 3.8 and 4 billion years ago, but the obvious subtext is the ignorance of geologists about earth history. “Geologists have posed several theories to explain this puzzle,” she noted about precious metals. Careful reading shows the Late Heavy Bombardment to be only an idea, a suggestion. Interesting as isotope comparisons are, they don’t provide a time machine. And saying that the age of Earth’s tungsten matches the dates of craters on the moon calibrates two questionable dates against each other. Nothing in the article provides evidence that meteorites are made of gold. It seems to move the question of the origin of precious metals from one body to another.
When all else fails, bring in a meteorite. When you can’t explain the moon, bring in a Mars-size meteorite to blast the Earth. When you can’t explain Earth’s oceans, imagine a giant water balloon comet to bring it special delivery. Meteor crashes are too convenient; they are the imaginary can openers that open any can for the hungry hobos. “Assume a can opener” makes the rest easy. Assume a meteor. Need water? Bring in a water meteor or comet. Need gold? Send in a gold meteor. Imaginary theory-saving devices to the rescue! Try that with your credit card debt.