Posted on 05/08/2017 1:25:53 PM PDT by JimSEA
More than 90% of Earth's continental crust is made up of silica-rich minerals, such as feldspar and quartz. But where did this silica-enriched material come from? And could it provide a clue in the search for life on other planets?
Conventional theory holds that all of the early Earth's crustal ingredients were formed by volcanic activity. Now, however, McGill University earth scientists Don Baker and Kassandra Sofonio have published a theory with a novel twist: some of the chemical components of this material settled onto Earth's early surface from the steamy atmosphere that prevailed at the time.
First, a bit of ancient geochemical history: Scientists believe that a Mars-sized planetoid plowed into the proto-Earth around 4.5 billion years ago, melting the Earth and turning it into an ocean of magma. In the wake of that impact -- which also created enough debris to form the moon -- the Earth's surface gradually cooled until it was more or less solid. Baker's new theory, like the conventional one, is based on that premise.
The atmosphere following that collision, however, consisted of high-temperature steam that dissolved rocks on the Earth's immediate surface -- "much like how sugar is dissolved in coffee," Baker explains. This is where the new wrinkle comes in. "These dissolved minerals rose to the upper atmosphere and cooled off, and then these silicate materials that were dissolved at the surface would start to separate out and fall back to Earth in what we call a silicate rain."
To test this theory, Baker and co-author Kassandra Sofonio, a McGill undergraduate research assistant, spent months developing a series of laboratory experiments designed to mimic the steamy conditions on early Earth. A mixture of bulk silicate earth materials and water was melted in air at 1,550 degrees Celsius, then ground to a powder. Small amounts of the powder, along with water, were then enclosed in gold palladium capsules, placed in a pressure vessel and heated to about 727 degrees Celsius and 100 times Earth's surface pressure to simulate conditions in the Earth's atmosphere about 1 million years after the moon-forming impact. After each experiment, samples were rapidly quenched and the material that had been dissolved in the high temperature steam analyzed.
The experiments were guided by other scientists' previous experiments on rock-water interactions at high pressures, and by the McGill team's own preliminary calculations, Baker notes. Even so, "we were surprised by the similarity of the dissolved silicate material produced by the experiments" to that found in the Earth's crust.
Their resulting paper, published in the journal Earth and Planetary Science Letters, posits a new theory of "aerial metasomatism" -- a term coined by Sofonio to describe the process by which silica minerals condensed and fell back to earth over about a million years, producing some of the earliest rock specimens known today.
"Our experiment shows the chemistry of this process," and could provide scientists with important clues as to which exoplanets might have the capacity to harbor life Baker says.
"This time in early Earth's history is still really exciting," he adds. "A lot of people think that life started very soon after these events that we're talking about. This is setting up the stages for the Earth being ready to support life."
“I can read, but I’m afraid this is way beyond my education & comprehension. The layers of rock along the Smoky Mountains are stunning and I have wondered how they were formed.”
The process that formed those mountains is still going on today.
The mississippi river sends sediment into the Gulf of Mexico. The sand settles out quickly and eventually gets buried deep enough that it forms sandstone. The finer slits and clay settle farther out and become siltstone and shale. (sedimentary process)
As time goes on they get buried deeper and deeper to the point heat and pressure change the sedimentary structures (layers) and new minerals are formed and separated out (metamorphism)
Then a couple of continents slam into each over a bazillion years and the whole mess gets uplifted, similar to sliding two floor rugs into each other.
After the two continents get tired of being married they separate. In the divorce North America kept most of the mountains (blue ridge) and Africa got screwed (Atlas Mountains).
The smokies used to rival the Himalayas. All we see now are the worn down stumps.
All this happens with several bazillion years, give or take a few.
Get one of those Thermoses that keeps things hot instead of cold.
Your thermos has an insulating value (R) of roughly 5. Since it's about a half inch thick, that gives it an R value of roughly 10 per inch. Dirt has an R value of about 1 per inch. The dirt is roughly 1,000,000 inches thick. That gives it a total insulating value of about 1,000,000, compared to your thermos of 5. Earth also has residual radioactivity making up for any loss. That's sort of like putting an electric heater inside your thermos.
Well, this Spring has been wet and cold with today being one of the few great days. I’m enjoying it.
With all the granite in the first land masses, the silica had to come from somewhere and it wasn’t in the mantle in sufficient amounts. This is one swag that seems to fit.
4,500,000,000 years x 365 days x 24 hours
vs
4 hours of keeping my soup hot
I still want a dirt thermos.
God has His own timeline and creation is so absolutely wonderful that I personally like the long time theory. Gives me some hope, too, that this crusty human can still be morphed into His image since that didn’t happen instantaneously either.
‘kay.
While I am a believer in both the value of scientific methodology ( not scientism- which is based on a myriad of “assumptions” made into natural “law”, which by self proclaimed virtue then eliminate all other posits and theories- see the “theory of evolution”), I also accept the obvious inability of “knowledge” ( science) to explain things that have no reasonable primary cause other than an external actor.
I really like Hawkings’ explanation of the beginning of the universe- he stated basically that “it had to come into being because it needed to”. Smart man huh?
A simple examination of that line of thinking is circular- and I mean really circular. Not a shred of “science” ( scientific method, I mean).
“Because there is a law such as gravity, the Universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the Universe exists, why we exist.”
(Roberts, L. Stephen Hawking: God was not needed to create the Universe. Telegraph. Posted on telegraph.co.uk September 2, 2010, accessed September 2, 2010.)
And the science ( knowledge) community bows down to such as he.
Basically he is saying that a closed system operates on its own- and no input is needed. He fails at level one. Nothing (not even physical laws), then something. Where did the law of gravity originate? Only bodies with mass and matter evidence gravity- no mass/matter, no gravity. Back to square one. He automatically provides the fatal flaw in his reasoning- that of assuming something already existed- the laws of physics?
Wow!
No reply necessary. It won’t help the “scientism” cause.
I wonder if I can get that in tomato?
Yes. In Japan.
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