Hyper Velocity Asteroids and Mantle Plumes

[DeathDart]

A hyper velocity asteroid impact at a velocity greater than 100 kms can easily punch through the crust and penetrate 100’s of miles into the mantle. At some depth in the Mantle the material appears to be elevated in Uranium and REE. Mantle plumes are the origin for the Uranium found in black shales. The uranium did not precipitate out of seawater as some would argue. The uranium can also indicate strata related to extinctions such as the end of the Permian. The Siberian Basalts started with a hyper velocity impact. Fifty percent of all species alive at this time went extinct.

A hyper velocity asteroid impact is quite different in its effects on the surface. At these high velocities the shock wave is much slower than the passage of the object. Less of the objects total energy is expended by shockwaves. The shockwave energy is the force applied multiplied by the interaction time. Less time for interaction (higher velocity), the less total energy lost to a surface shockwave.

So the surface crater is not very big. They do produce a lot of flood basalts because the detonation of the asteroid produces massive heating of huge volumes of magma. Plus a lot of lighter surface material gets dragged deep into the mantle.

A hyper velocity asteroid impact is quite different from one at 15 kilometers per second (kms) kilometers per second. Because of orbital physics anything going faster than about 50 kms has to come from outside the Solar System. Nothing can enter this Solar System from the universe because the Solar System is protected by a force field.

Star proper motion for nearby stars converted to linear relative motion can produce a velocity difference of 25 to 400+ kms. Guess who is coming to dinner and it isn’t Sidney Poitier.

The majority of stars that go past the solar system are red or brown dwarfs. These stars burn very slowly, and can last for over a 100 billion years. They can be nearly the age of the universe. They may have orbiting asteroids left over from their formation, these asteroids would also be old.

The age of the passing stars can be important if the 238U/235U ratio found in impact related material is not the Solar Systems 137.8. It is now standard to spike with 235U so this ratio is always assumed to be 137.8 Any evidence to the contrary is not documented.

If they are fast enough they tend to punch through the earth’s crust (25 miles thick) without leaving much of a crater. They do produce a lot of flood basalts.

Newtons argument that when enough material (mass) is accelerated by the impacting object, the object stops is only true if the impacting objects surface area remains the same.

An object moving at velocities near or above 100kms may self focus by a very strange mechanism. It may literally collapse into a narrower and denser kinetic object.

The very slow slower impact velocity chosen by Melosh and Ivanov was intentionally deceptive. Impacts do not initiate volcanic eruptions:
Eruptions close to the crater: Geology, v. 31, p. 869–872.

Of course there isn’t any force fields around anything except Geochronology Centers that could measure the 238U/235U ratio, or any computer facility that could run a computer simulation of a hyper velocity impact. These resources were jealously protected.

The Planet is covered (20 to 30 % of the surface area) in buried craters and hiding that concept makes finding oil a lot harder for people who don’t know that they exist.

 

[Molinaro]

The maximum velocity that a meteor or comet in orbit around the sun can hit the earth is 72 km/s.

Explain where these > 100 km/s objects get their speed.

Thanks.

 

[marplots]

The maximum velocity that a meteor or comet in orbit around the sun can hit the earth is 72 km/s.

Explain where these > 100 km/s objects get their speed.

Thanks.

Hemis.

 

[Puppycow]

The maximum velocity that a meteor or comet in orbit around the sun can hit the earth is 72 km/s.

Explain where these > 100 km/s objects get their speed.

Thanks.

Something that's not in orbit around the sun?

E.g. supernova debris? Or something cast off from another star system?

 

[Mark6]

A comet might pass very close to Jupiter, and get thrown into hyperbolic orbit. If that orbit brings it first toward the Sun, and Earth happens to be on its way, such impact could happen. Extremely unlikely though.

 

[Buckaroo]

A hyper velocity asteroid impact at a velocity greater than 100 kms can easily punch through the crust and penetrate 100’s of miles into the mantle. At some depth in the Mantle the material appears to be elevated in Uranium and REE. Mantle plumes are the origin for the Uranium found in black shales. The uranium did not precipitate out of seawater as some would argue. The uranium can also indicate strata related to extinctions such as the end of the Permian. The Siberian Basalts started with a hyper velocity impact. Fifty percent of all species alive at this time went extinct.

A hyper velocity asteroid impact is quite different in its effects on the surface. At these high velocities the shock wave is much slower than the passage of the object. Less of the objects total energy is expended by shockwaves. The shockwave energy is the force applied multiplied by the interaction time. Less time for interaction (higher velocity), the less total energy lost to a surface shockwave.

So the surface crater is not very big. They do produce a lot of flood basalts because the detonation of the asteroid produces massive heating of huge volumes of magma. Plus a lot of lighter surface material gets dragged deep into the mantle.

A hyper velocity asteroid impact is quite different from one at 15 kilometers per second (kms) kilometers per second. Because of orbital physics anything going faster than about 50 kms has to come from outside the Solar System. Nothing can enter this Solar System from the universe because the Solar System is protected by a force field.

Star proper motion for nearby stars converted to linear relative motion can produce a velocity difference of 25 to 400+ kms. Guess who is coming to dinner and it isn’t Sidney Poitier.

The majority of stars that go past the solar system are red or brown dwarfs. These stars burn very slowly, and can last for over a 100 billion years. They can be nearly the age of the universe. They may have orbiting asteroids left over from their formation, these asteroids would also be old.

The age of the passing stars can be important if the 238U/235U ratio found in impact related material is not the Solar Systems 137.8. It is now standard to spike with 235U so this ratio is always assumed to be 137.8 Any evidence to the contrary is not documented.

If they are fast enough they tend to punch through the earth’s crust (25 miles thick) without leaving much of a crater. They do produce a lot of flood basalts.

Newtons argument that when enough material (mass) is accelerated by the impacting object, the object stops is only true if the impacting objects surface area remains the same.

An object moving at velocities near or above 100kms may self focus by a very strange mechanism. It may literally collapse into a narrower and denser kinetic object.

The very slow slower impact velocity chosen by Melosh and Ivanov was intentionally deceptive. Impacts do not initiate volcanic eruptions:
Eruptions close to the crater: Geology, v. 31, p. 869–872.

Of course there isn’t any force fields around anything except Geochronology Centers that could measure the 238U/235U ratio, or any computer facility that could run a computer simulation of a hyper velocity impact. These resources were jealously protected.

The Planet is covered (20 to 30 % of the surface area) in buried craters and hiding that concept makes finding oil a lot harder for people who don’t know that they exist.

And...?

 

[DeathDart]

Something that's not in orbit around the sun?

No it is part of a different solar system or is independent and moving in interstellar space.

It is arrived at by converting proper motion of nearby stars to velocity. If the proper motion were directly at this Solar System then asteroids or other material from that system would enter at a high velocity relative to asteroids orbiting this Solar System.

 

[DeathDart]

It is a dangerous neighborhood out there. The Solar Sytem moves around a lot relative to nearby stars. One is supposed to come within 1 light year in about a million years. This isn't that close and nothing will come of it. Anything under about a 1/10th of a light year gets much more interesting.

 

[DeathDart]

If they are fast enough they tend to punch through the earth’s crust (25 miles thick) without leaving much of a crater. A lot of lighter crustal material is dragged in with thee asteroid. Between the lighter material and the heated magma the plume can last as many as 10's of millions of years

The Asteroid continues into the mantle where it detonates. The detonation releases tremendous amounts of kinetic energy which heats ten of thousands of cubic miles of material by hundreds of degrees. I do not know if the pressure at this depth would allow the formation of gases or not. These vaporized material (as gases) will explosively force out magma and surface debris through the small opening in the surface.

This ballistic fountain may send some components for thousands of miles in all directions. The fountain can be directional if the hyper velocity impact were at a low angle. Unlike a slow surface impact, the incoming asteroid path is more like a tube through the crust. At a low angle the fountain becomes more directional. The impact at the Columbia River Basalts appears to be coming in at a low angle from the Northwest. Ballistic spherules or material will probably be found to the north perhaps as far as the Bay of Alaska. If spherules are found there, they may match both the chemistry and the age of the Columbia River Basalts.

The basalt blasted across the planet is Tholeiitic basalt which is chemically reduced. It is chemically active and will absorb oxygen from the environment. When it falls to the bottom of shallow seas it will make the bottom anoxic (oxygen deprived). Some of the material delivered to to sea bottom will be uranium and Rare Earth Elements REE. The Uranium and other materials will cause the anoxic conditions, not the other way around as argued by the Big Oil Companies.

 

[Dinwar]

Explain how something can move directly from the mantle to surface deposits.

The Permian mass extinction was vastly more complex than you're attempting to portray it as. The flood basalts didn't help, but neither did....well, the short version is "anything else going on at the time". It was a really, really nasty time to be alive.

Explain why pressure release melting doesn't occur in your scenario.

Explain why oil companies are ignoring those craters covering 20-30% of the subsurface of the planet.

This entire concept is all speculation. Do you have any actual data?

 

[DeathDart]

Explain how something can move directly from the mantle to surface deposits.

The Permian mass extinction was vastly more complex than you're attempting to portray it as. The flood basalts didn't help, but neither did....well, the short version is "anything else going on at the time". It was a really, really nasty time to be alive.

Explain why pressure release melting doesn't occur in your scenario.

Explain why oil companies are ignoring those craters covering 20-30% of the subsurface of the planet.

This entire concept is all speculation. Do you have any actual data?

The Siberian Basalts were not that dangerous, compared to what?

Pressure release melting does occur in my scenario, but it is minor portion of the temperature rise in the basalt. The detonation of the asteroid 100's of kilometers below the surface is the power source for the eruptions. The detonation can release huge amounts of energy (greater than 1 billion megatons) which can transfer as a several hundred degree temperature rise in as much as 100K Cubic Kilometers of Material.

Why do they go through the trouble to spike Geochronometric measurements with 235U?

Any uranium from this solar system has a current 238U/235U ratio of approximately 137.8 plus/minus .4. Anything of substantial mass from a different uranium source (different supernova origin of material) will change this ratio. The 235U spike hides any change in the ratio.

I was not the first to find this mantle plumes by hyper velocity asteroid scenario. Actually I seem to be about 40 years behind other groups. The efforts to hide this evidence would not be for any valid scientific reasons though economic reasons could be a strong motive.

 

[DeathDart]

Explain how something can move directly from the mantle to surface deposits.

It can follow the channel blasted by the passage of a hyper velocity asteroid. The asteroid physically blasts a channel deep into the mantle.
The passage is briefly open after the passage. The passage of the asteroid has disrupted the structure of the mantle. It is no longer a cohesive structure capable of blocking the heated and expanding mantle material. The material close to the surface will be mixed with the vaporized material rising from the detonation deep in the mantle.

The transfer of kinetic energy to the basalt, uranium, and Rare Earth Elements (REE) will vaporize them and send them back along the asteroids path. The violence of this basaltic eruption is mechanically less severe compared to a shallow detonation, but the long term biological effects are persistant and devastating.

That is why black shales are high in uranium and REE. Lots of dead stuff which couldn't decay also makes it rich in organic compounds.

 

[DeathDart]

Asteroid Diameter 10 kilometers

Mass 2.67 grams centimeter^3

Total Mass 1.39801E+15 kilograms

Velocity 100000 meters per second

Kinetic Energy 6.99004E+24 Joules

1 megaton= 4.184E+15 Joules

Amount of energy delivered to mantle material (50% of Total)

Energy delivered 8.353E+08 megatons or 3.49502E+24 Joules

Picture basalt fountains going above the top of the atmosphere.

 

[wollery]

Now, would you care to calculate the impact cross-section of an interstellar asteroid and the Earth, taking into account the cross-sections of the Sun and the rest of the planets?

I feel it may be a little enlightening for you.

 

[DeathDart]

Now, would you care to calculate the impact cross-section of an interstellar asteroid and the Earth, taking into account the cross-sections of the Sun and the rest of the planets?

I feel it may be a little enlightening for you.

So would taking that impact cross section and viewing it over a 100 million year period of time.

Yes, it has to hit you on the first pass, since it will never be back again.

The cross section of the sun and other planets are almost irrelevant. They are only relevant if they happened to be somewhere along the Earth intercept line and caught the asteroid instead of Earth.

Low probability and disastrous.

And I am at least 40 years behind the people who found out about this mechanism for global extinctions.

A mechanism which they appeared to be trying to hide.

 

[mike3]

Explain how something can move directly from the mantle to surface deposits.

The Permian mass extinction was vastly more complex than you're attempting to portray it as. The flood basalts didn't help, but neither did....well, the short version is "anything else going on at the time". It was a really, really nasty time to be alive.

So does this mean that if a similar flood eruption happened with different conditions present, the effects could be much less severe? And also, that even if the flood eruption didn't happen, there could still have been a big extinction (though perhaps not as big?) due to all the other factors?

 

[wollery]

So would taking that impact cross section and viewing it over a 100 million year period of time.

Yes, it has to hit you on the first pass, since it will never be back again.

The cross section of the sun and other planets are almost irrelevant. They are only relevant if they happened to be somewhere along the Earth intercept line and caught the asteroid instead of Earth.

Low probability and disastrous.

I'm not sure "low probability" quite encompasses it.

A couple more questions:

Why are the cross-sections of the Sun and other planets irrelevant?

Have you any idea how many stars have "proper motions" aimed directly at the Solar system?





p.s. for the interested observers and pedants out there, I'll get on to the misconceptions about proper motion and where it has to be aimed later, if it seems necessary.

 

[Dinwar]

It can follow the channel blasted by the passage of a hyper velocity asteroid.

Not without disturbing the stratigraphy--or, more accurately, destroying it. We don't observe that. I don't give a rat's tail about the mantle here; I'm talking about the stratigraphy of the black shales. Your evasion of that concept suggests an unfamiliarity with modern geology, which is obnoxious in someone attempting to overthrow it.

The Siberian Basalts were not that dangerous, compared to what?

This doesn't make sense given the statement I made.

Pressure release melting does occur in my scenario, but it is minor portion of the temperature rise in the basalt.

You think TEMPERATURE has something to do with pressure release melting?! Go take an introductory geology class, please. Learn at least SOMETHING about geology before attempting to tell me how to do my job.

So does this mean that if a similar flood eruption happened with different conditions present, the effects could be much less severe?

Well....yeah. Flood basalts are only correlated with mass extinctions when you look at mass extinctions and note the flood basalts that happen around that time. When you look at all flood basalts you find a surprising number not associated with mass extinctions. So yeah, flood basalts can occur without killing significant portions of life on Earth.

And also, that even if the flood eruption didn't happen, there could still have been a big extinction (though perhaps not as big?) due to all the other factors?

It's impossible to say how big the extinctions would have been (there were two), but if you put a gun to my head I'd say that they'd still be massive. You have to understand, the world basically went into worst-case scenario for life. Massive desertification, the loss of huge volumes of near-shore environments, the complete shutdown of incredibly important ocean currents--Pangea, by simply existing, was going to hurt life a LOT. Add to that a major ice age (as recorded by Late Permian cyclothems) followed by massive global warming, and life was just getting beat down.

 

[Dinwar]

Because I've had like three hours of sleep and six cups of coffee, I've decided that my previous post wasn't sufficient. I want to explore pressure release melting a bit more, and demonstrate why an impact that cracks the crust will necessarily result in an explosion.

First, you have to understand that temperature alone isn't really sufficient to discuss geology at this scale. The important bit is the relationship between temperature and pressure--or, in geo-speak, P-T Space. Each mineral is stable within a certain region in P-T space. In other regions, it's meta-stable--meaning that it's fine as long as you don't heat it up or otherwise allow crystalization to occur. Diamonds and olivine, for example, are meta-stable at surface temperatures and pressures. You can convert diamonds to graphite by heating them up (do not do this with your spouse's diamond rings). You can also accomplish this with no change in temperature, by changing the pressure the minerals are at.

This is actually pretty intuitive. Pressure cookers, for example, run on this exact principle. Steam generated by boiling water increases pressure in the pot, increasing the boiling point. Release it too fast, and you get burned badly and can die. That's why they have safety valves, to avoid that catastrophic phase change. We're really discussing the same thing here: a phase change controlled by pressure changes, only in the case of the mantle it's largely going from solid to liquid rather than liquid to gas.

Only.....it gets worse. The mantle includes materials that are gas at surface temperatures and pressures. Water, for example. Half the reason that felsic volcanoes explode while mafic volcanoes don't is that felsic magma has a lot more water in it. Basically, think of opening a soda bottle. Take the pressure off, it effervesces. In soda, this provides that pleasant tingle. In molten rock, this results in flinging molten shards of rock all over the place. Add in the water from the oceans (remember, 75%+ of the planet is covered in them, so odds are if the OP's scenario happens it'll be in the water) and it gets more fun.

So ignoring the fact that the impacter will be largely vaporized during the impact, simply opening the mantle to surface temperatures and pressures would result in a catastrophic explosion due to an extremely rapid phase change and effervescence from out-gassing. The result wouldn't be a basaltic lava flow, but a giant gaping hole in the crust. And that's leaving out the heat generated from the impact; once you add that in (and the amount of rock instantly vaporized) and this event becomes vastly more violent than the OP assumes.

The K/Pg impact released more energy than would be released if all nuclear warheads ever to exist were fired off. 10 times more energy is on the conservative side. Even assuming that the rock punched through the crust without much energy transfer (in other words, playing make-believe), you're still going to instantly boil millions of cubic MILES of rock. The phase change alone will release an amount of energy that's simply unimaginable.

 

[DeathDart]

So does this mean that if a similar flood eruption happened with different conditions present, the effects could be much less severe? And also, that even if the flood eruption didn't happen, there could still have been a big extinction (though perhaps not as big?) due to all the other factors?

Mantle plumes by impact are far more likely the cause for large igneous provinces than a “true” deep mantle upwardly growing plume. The plumes that feed the midocean ridges extrude less than (a guess) 10 cubic kilometers per year. And they are spread out over thousands of miles.

Internal plumes have slow eruptions and they don’t have the concentrated energy source of the impact detonation at depth. So impacts provide the energy to heat, thin out, and eject the magma. Natural plumes are many times more thermally diffuse and have much less total energy to work with.

Terrestrial causes tend to be much milder and localized. Yellowstone doesn’t count since it is a plume.