Magma for Dummies - The Freelance Files MMXCIV

Magma is not everywhere inside the Earth, Tricia!

We don't know about everybody else, but around our shop we are all of the same opinion: when we start reading something that is supposed to be informative and the first sentence is bullshit, we have a hard time believing that anything else in the text is going to be right, correct, true, real, or whatever affirmative you decide to use. That's why when one of the staffers turned up a post at the recently created WiseGEEK.com niche site AllThingsNature.org called "What Is Magma?" we knew right away that Tricia Christensen (sometimes Tricia Ellis-Christensen) was headed for the award podium. Maybe her editor O. Wallace should accompany her...

Why do we say that? Because Christensen opened her post with one of the most common bogus claims about the structure of the Earth:

"Several kilometers below earth’s crust, hard rock is replaced by softer rock, and then ultimately by liquid rock with gases and minerals, that occasionally erupt from volcanoes or cracks in the earth."

OK, so the bogosity is (mostly) in sentence two: so sue us. Whatever the case, Tricia's assertion that the interior of the planet is a vast bubbling cauldron of "liquid rock with gases and minerals" would even be bullshit if the planet were hollow and filled with liquid, because "liquid rock" – Tricia's phrase for magma – wouldn't be accompanied by minerals since the stuff IS melted minerals. What an idjit!

Once Tricia got that crapola out of the way, she bounded off into cloud-cuckoo land, regurgitating a spate of semi-accurate factoids; stuff like,

"Though a few materials melt at temperatures of about 1100 degrees F (593.33 C), most magma under the earth’s crust maintains temperatures between 1292 and 2372 degrees F (700-1300 C)."

That's reworded from a Wikipedia article about magma, which mentions those low-temperature carbonatite magmas. We find Tricia's insistence on precise Fahrenheit temperatures... so amusing... especially since it's one of the calling cards of the scientifically illiterate. Then there's this claim:

"Some scientists make the distinction between magma and lava, defining lava as molten rock that is on or above the earth’s surface."

No, Tricia, all scientists (as opposed to English Lit grads) make that distinction, although few of them think lava is "above the earth’s surface"; except perhaps in an explosive eruption. She also "informs us next that, "This can also be called extrusive." Uhhh, yeah: that's what it's called: what else would you call it?

There's a boatload more of similar rubbish, but we figure you're either tired of reading the stuff or have already given up. Whatever the case, we'll leave you with one final quote:

"Obsidian, for instance, is shiny and brittle, and somewhat resembles the flow of certain types of magma."

We honestly can't parse that bullshit. You? If you can figure out what "the flow of certain types of magma" is supposed to mean, we'll let you present our Dumbass of the Day this well-deserved award. Otherwise, she can drop by and pick it up herself.

SI - GEOLOGY