I'll bet you were as surprised as anyone was to read that article about portions of the inside of the Earth having a peanut butter-like consistency. If you haven't maybe you haven't read that article. Go ahead and find it now; I can wait. I have my little puzzles and my memories. Once you're back, aren't you as surprised as anyone is? Well, except for the people who were drilling down into the Earth hoping to find oil and dug up peanut butter instead. Maybe it's more accurate to say we're as surprised as some people will be.
Anyway it makes perfect sense there'd be large regions of the Earth's mantle made of peanut butter, since that's part of the natural interior flow processes which produce diamonds, in mines hidden in the crust, and ferromagnetic nougat, in the core of the planet. This nougat core is critical to life as it provides not just the global magnetic field but also that sweet, slightly sugary smell in the ionosphere which protects us from the ``solar wind'' of rainbow sprinkles.
Now with the peanut butter in the interior better established we can understand the personality quirk of ``pica'', the eating of dirt or clay. Dirt would be ridiculous to eat, but suppose it were peanut butter dust? How about if it were mixed in with crumbled cookies or maybe graham crackers? Now suddenly it's folks who don't eat dirt who come across as the ridiculous ones. Who knows what we're missing by not taking other objects found around nature -- trees, chain link fences, cars, Canadian geese -- and shoving them into our mouths? In the first case we're missing out on being attacked by angry home-owning chipmunks, and in the second we're missing out on a lot of honking and vicious pecking. I don't want to get into the other cases.
Interesting story about pica: we're able to use that word to describe eating dirt and clay now without running the risk of confusion because we don't need it to describe types of typewriter type anymore. There had been pica, elite, Gold Card, Platinum, and Courier Old Blah typewriters, and until 1986 we had no choice but to eat the typewriters. But fortunately then Tetris was invented, and it forced people to buy computers because the game was much too tedious to play over the typewriter, and we could reach the happy state now where we just have one typewriter sitting in the corner staring ominously, yet dusty, at the young. And the young probably don't even imagine licking it.
All this peanut butter stuff seems to be in the magma, which is hidden from us by the end of the crust. That end is known as the Moho, because it would be too much bother to use the full name of the Moho Discontinuity. The name actually should be longer than that, but it can't be, because Moho is short for Andrija Mohorovicic, and even that's wrong because his last name has special accent and character features and can't be written in fewer than six dimensions of space. But he was a great geologist and thanks to him we know of the delicious layer of dark chocolate underneath our continental shelves.
That the Earth should deep down be so delicious shouldn't really be a surprise. The idea of a candy-based origin for the planet dates back to Immanuel Kant's 1755 Allgemeine Naturgeschichte, which contained the first known speculation that the planets and Sun had formed by falling out of a candy shop in Königsberg. The passage containing this was for centuries believed to be a printing error that got a few pages from Charlie and the Chocolate Factory slipped into his manuscript. It was a relief when Roald Dahl finally got around to writing Charlie and the Chocolate Factory in 1961 and he didn't include anything remotely like that. And is it pure coincidence that this discovery came about the time the ``Project Mohole'' excavation to the Moho was cancelled and the giant hole dug up and moved to be the Chesapeake Bay Bridge-Tunnel? Yes, but it's a neat one anyway. Who doesn't like surprises?
Trivia: In May 1576 Spain's King Philip II issued a questionnaire with 49 questions to be answered by all Spanish officials in the Americas. Answers began to arrive in 1577, and continued to arrive through 1587. Source: Empire: How Spain Became A World Power, 1492 - 1763, Henry Kamen.
Currently Reading: Project Pope, Clifford Simak.