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Jan de Boer

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Lets reconsider the basics of several sciences. Step 1. The crust of our Earth is floating on...... On what?

Several sciences are based on incorrect assumptions.
That could be expected. We are all suffering sometimes from tunnel vision, blind spots, not-made-here, political correctness, stubbornness and so on.
So, lets have a look at some “facts”, decide what is wrong about them and leave it to the scientists to tie up the loose ends in a proper scientific way.

They told us at school: “The crust of our Earth is floating on liquid magma.”..... Is that true?
How do you tackle this question?
My way is to estimate the conditions at the underside of the tectonic plates.
First the pressure. Taking in account their thickness, the specific weight of the materials, I come to a pressure of some 20,000 bar plus or minus a few thousands.
Second the temperature. Taking in account their thickness and the temperature gradient I come to a temperature of some 2,000°C plus or minus a few hundreds.
Third, the nature of the material below the crust. If this material is liquid, then the heavier materials will sink down and the lighter materials will move up.
Given the fact that Earth is old, the segregation must have been completed long ago.
Lets look at the lighter atoms and molecules. Most of them are well above their critical point even at 1,000°C and therefor not liquid but gas. Examples are hydrogen, helium, nitrogen, sulpher, sodium and above all carbon-dioxide and water.
An average volcano emits some 500 tons CO2 per hour. There are some 1,500 active volcanoes. Add the emission of sleeping and dead volcanoes and you get a total emission of some ten billion tons CO2 each year. This has been going on for a few billion years, so the crust of our Earth is not floating on liquid lava, but is, like a hovercraft, floating on gas. A mixture of gases, so hot that they are ionized and many are dissociated.

Do you agree so far? If not, proof that I'm wrong.

Next, step 2: Voyage to the center of the Earth.

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  • May 21 2012: Hey, guys, he's right you know. The crust is very heavy and it does sink ( subduction zones ), but even though it sinks doesn't mean that its heavier than the material below it. Hence why we see the same material’s coming back up in volcanoes. He is also right in the sense that there is an exceptional amount of gas under the crust, but where it comes from and where it goes are two different matters. Most of these gasses are brought down through subduction. Our oceanic crust is the culprit mostly, bringing with it millions of tons of water and carbon dioxide, the carbon being in the form of dead see life, and ocean sediments, and as these sediments, rocks, and water are heated up and melted. The water and carbon turn to gas, but my friends as we know gas is much lighter than rock. Even at tremendous pressures. So the gas tries to escape, forcing itself up through our crust, mixing with molten rock until it reaches the surface, forming our planets volcanoes and releasing Co2 and water into the atmosphere. This process is just one part of the Carbon and Water cycle's. As for what the plates float on it is commonly believed to be Olivine, slightly denser than crust rock, though a thin layer, enough to make the plates rides a smooth one.
    • May 21 2012: Hi Jarred
      One small correction: Gas is not always lighter than rock. Normal air, the kind we inhale, has a weight of 1.4 kg/m3. Increase the pressure to 20,000 bar and the weight runs up to 28,000 kg/m3. almost ten times heavier than rock. Increase the temperature to 2,000°C, then the gas expands to some 8 m3 and the specific weight goes down to some 3.500 kg/m3 which is definitely more than the some 3,000 kg/m3 of rock.
      • May 21 2012: Thanks, I was just trying to make a point but you are right in that respect.

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