Cataclysm at Meteor Crater: Crystal sheds light on Earth, moon, Mars (Update)

Cataclysm at Meteor Crater: Crystal sheds light on Earth, moon, Mars
Crystals extracted from a rubble pile collected a century ago by prospectors at Meteor Crater showed extreme temperatures and pressures during the impact that created the crater 49,000 years ago. Credit: Aaron Cavosie

In molten sandstone extracted by prospectors a century ago, an international team of scientists has discovered microscopic crystals telling of unimaginable pressures and temperatures when a 50-meter asteroid (traveling 12 kilometers per second) formed Meteor Crater in northern Arizona some 49,000 years ago.

The crystals, called zircons, have endured temperatures of 2,000 degrees Celsius or more, hot enough to melt any rock on Earth. In our planet's crust, such temperatures occur only briefly inside impact zones, says Aaron Cavosie, a visiting professor in the Wisconsin Astrobiology Research Consortium at the University of Wisconsin-Madison.

Zircons are tiny, phenomenally stable crystals that can persist for billions of years and have been used to date ancient asteroid impacts. But the new study, now online in the journal Geology, sheds light on a more recent impact at Meteor Crater, which may be the best studied impact zone on Earth. "It's fresh, young and easy to get to," says Cavosie, who is also a senior research fellow at the Western Australian School of Mines, Curtin University, in Perth, Australia.

In an electron microscope, the zircons look like agglomerations of BBs. Such "granular" zircons are also found in a giant impact crater in South Africa and on the moon, "but until now no one has cracked the code to figure out what turned normal zircons into thousands of grains glued together," Cavosie says.

Cavosie's group, including Nick Timms and Curtin Ph.D. candidate Timmons Erickson, along with collaborators Justin Hagerty from the U.S. Geological Survey and Fred Hörz from NASA, strung together several lines of evidence to conclude that the zircons had been subjected to a pressure of at least 300,000 atmospheres, and temperatures above 2,000 degrees C.

When the researchers fired a beam of electrons at 14 zircons, the electrons scattered back to a detector revealed the chemistry and the complex structure of the zircons. "When we looked at the texture of these unusual zircons, we saw that the orientations of the BBs are non-random, and instead are highly systematic," Cavosie says.

These zircons are so tiny that eight, lined up, would extend across the width of a hair.

The orientations "record a series of changes that happen as zircons get shocked at increasing pressures - think Dante's levels of hell for zircons," Cavosie says. A moderate level of shock creates planar cleavages, "but as you go to higher levels, the zircon makes a twin, which is what happens when parts of a crystal are forced into a different orientation. This specific change is only caused by impact, and we have seen it in other places."

Cataclysm at Meteor Crater: Crystal sheds light on Earth, moon, Mars
New research at Meteor Crater shows extreme temperatures and pressures during the impact that created the crater 49,000 years ago. Credit: Aaron Cavosie

Another distinctive orientation "only forms when zircon changes to the extremely rare mineral reidite," Cavosie says. "This transformation is proven in the lab to require even more than twins."

Finally, the impact created such an extraordinarily high temperature that it vaporized or melted all rocks in the surrounding crust. The quartz grains in the sandstone fused into the glassy, "shock-melted silica" that encased the zircons.

"When we screwed all these parts together," Cavosie says, "the orientation of the granular zircons, the pressure required to form the twin phase and then reidite, and the finding that zircons were briefly swimming in a pool of liquid silica at about 2,000 degrees, hot enough for the zircons to recrystallize into this beebee-like granular texture, and then the evidence that this cooled very quickly, we saw that the granular zircons left a trail of breadcrumbs that allowed us to reconstruct how they were made, and in what conditions."

Extreme pressures and temperatures that quickly subside comprise an unusual realm for geology. "Geologists are used to thinking about slow processes," Cavosie says. "The process that transforms carbon into diamond is slow and steady; it involves high pressure and temperature but happens over millions of years."

The equally dramatic transformation that creates a granular zircon occurs over a few minutes at most. "Then, the extreme pressure is gone, the high temperature has cooled off," Cavosie says. "The impact leaves a giant hole in the ground, but it takes a mental adventure to wrap your head around the fact that the transformation in these zircons happened in seconds to minutes."

The significance of understanding the formation of granular zircons extends far beyond one large meteor crater, Cavosie says. "These granular zircons have been found in meteorites, whose history we know very little about. Now, when we find them in a meteorite, it will allow us to recreate the conditions that the meteorite experienced on its path to Earth."

The same is true for rocks returned from Mars and the moon, Cavosie says, and indeed he's already investigating some moon rocks returned by the Apollo program.

"The new diagnostic techniques reported by Cavosie and colleagues will aid in cataloging impact events on Earth and elsewhere in the solar system," says zircon expert John Valley, a professor of geoscience at UW-Madison. "This is important for understanding the history of Earth and the emergence of life. It will also aid in predicting the frequency of future large impacts to Earth, equivalent to the one that killed off the dinosaurs 65 million years ago, nearly extinguishing all life on land."


Explore further

Study questions dates for cataclysms on early moon, Earth

Journal information: Geology

Citation: Cataclysm at Meteor Crater: Crystal sheds light on Earth, moon, Mars (Update) (2016, July 26) retrieved 17 July 2019 from https://phys.org/news/2016-07-cataclysm-meteor-crater-crystal-earth.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
573 shares

Feedback to editors

User comments

Jul 26, 2016
Ugghhh! where are the editors when you need them. The Barringer crater was not formed from a 12 km asteroid! The crater itself is only 1,200 m (1.2 km) in diameter.

This site is worthy of better review of the content.

Jul 26, 2016
A "12-kilometer asteroid", as reported above, seems a bit much when the crater is only about 1.2km in diameter. Estimates of the impacting meteor's size range from 45m to 50m in diameter.

Jul 26, 2016
I believe you meant to give the size as 120 meters, perhaps? A "12-kilometer asteroid" would be 6 times larger than the crater - comparable to the one that ended the Age of Dinosaurs!

Jul 26, 2016
There is a much, much simpler explanation of the above wild conjecture. Electric discharge can explain these events much more concisely and it can be verified by experiments unlike the guesses above.

Jul 26, 2016
There is a much, much simpler explanation of the above wild conjecture. Electric discharge can explain these events much more concisely and it can be verified by experiments unlike the guesses above.

Aaaannnddd - this discharge was generated how?

Jul 26, 2016
This comment has been removed by a moderator.

Jul 26, 2016
This comment has been removed by a moderator.

Jul 26, 2016
Re: "Aaaannnddd - this discharge was generated how?"
Simple: Two objects travel through space of dramatically differing charge densities. Then, they come in close proximity.

Your previous comment wasn't bad (to this one).
But -
Have you considered the amount of charge differential required just to heat the crystals and surrounding environment to granulation point? Now consider how much MORE would be required to move all the dirt from the "sizeable" impact crater?
Truthfully, the questions should be directed at yourself as to what assumptions you've failed to question which have created your own failure of imagination.

My imagination does just fine, thank you. Truth is, I don't accept others assumptions as fact and consider way more variables than most would, as a result...
Cuz I'm a DIY guy from Missouri? :-)

Jul 26, 2016
This comment has been removed by a moderator.

Jul 26, 2016
Zircon dating is a form of thermoluminescence dating. Charles Ginenthal commented on this technique in his essay "Scientific Dating Methods In Ruins" ...

"this process works because ... so as to calculate a date for the age of the artifact."
In other words, the technique makes a crucial assumption about the electrical conditions since the event occurred.

And - scratch my comment about your previous comment being not bad.
They're not even considering thermoluminescence or electrical conditions since. They are looking at physical arrangement characteristics that occurred at the TIME of impact.

Jul 26, 2016
This comment has been removed by a moderator.

Jul 26, 2016
This comment has been removed by a moderator.

Jul 26, 2016
It's not extraordinary in terms of the numerous astronomical observations of electricity through space which are today ignored by gravitationalists.

Such as..?
The very fact that gravity exhibits such difficulties doing the work that is observed should give you some pause.

You do realize kinetic energy is a byproduct of gravity, don't you?
If it is really true, as claimed, that gravity is a side effect of electrical charge or electrical flow over plasmas, then the relative stability of G dictates that we are talking about very large amounts of charge.

Nope. Other way around.
The idea that every once in a while, the system's stability would be undermined, resulting in some discharge, is not actually extraordinary.

No it isn't. But a discharge of the magnitude required to do so is unavailable on this planet.
Same sort of stuff happens on transmission lines -- long periods of stability punctuated by violence.

Apples and pomegranates..

Jul 26, 2016
Re: "They're not even considering thermoluminescence or electrical conditions since. They are looking at physical arrangement characteristics that occurred at the TIME of impact."

The zircons replenish the electron content of the material, which is why they imagine that they can simply count electrons through TL.

They are looking at actual structural characteristics - not counting electrons...

Jul 26, 2016
Truthfully, the questions should be directed at yourself as to what assumptions you've failed to question which have created your own failure of imagination.
@chris
actually, this is more demonstrative of your own failures and bias

Science keeps an open mind and follows the evidence... this is evident from GR/SR (even historically, as you like to note that history is important) to astrophysics

considering we actually have evidence of physical impacts that we've watched, and we have seen/know how destructive they can be, and we know what kinds of evidence they will/do leave...

which is the more probable event: the physical collision or the plasma discharge?

before you answer, remember:
there is absolutely no evidence of plasma discharge of this scale ever observed or known
AND
there would be a lot of physical evidence that exists still today that would prove a plasma discharge

and there is your answer!

(hint) if you chose plasma, the problem is all yours

Jul 26, 2016
There is a much, much simpler explanation of the above wild conjecture. Electric discharge can explain these events much more concisely and it can be verified by experiments unlike the guesses above.


Aaaannnddd - this discharge was generated how?

Something like this;
http://phys.org/n...tic.html

Only a bit larger and closer.

Jul 27, 2016
There is a much, much simpler explanation of the above wild conjecture. Electric discharge can explain these events much more concisely and it can be verified by experiments unlike the guesses above.

Absolute, complete and utter bullocks. Electrical discharge CANNOT explain the heat, the formation of zircon twins, the shocked quartz, the shocked silica, the silica melt sheets, the temperatures, the melted and vaporized impactor, the recovery of pieces of the impactor, or pretty much any other aspect of this impact crater.

It is a LAUGHABLE position to take that this IN ANY WAY resembles an electrical discharge crater. Well, except in an imaginary world created by a story teller who saw gods in ancient cave paintings.

Jul 27, 2016
There is a much, much simpler explanation of the above wild conjecture. Electric discharge can explain these events much more concisely and it can be verified by experiments unlike the guesses above.


Aaaannnddd - this discharge was generated how?

Something like this;
Only a bit larger and closer
And without causing most of the effects. And while leaving no sign how it occurred. And not explaining the impactor fragments. And without being able to create the heat. And without being able to create the shocked crystals. And without being able to produce the zircon twinning. And without being able to produce the zircon aggregates. And without being able to produce the silica melt sheet. And without being able to produce the pressure. And without being able to produce the temperature.

But other than that, it is "similar". It "looks like" it "could be" "consistent with". Words of pseudo-science.

Jul 27, 2016
Ugghhh! where are the editors when you need them. The Barringer crater was not formed from a 12 km asteroid! The crater itself is only 1,200 m (1.2 km) in diameter.

This site is worthy of better review of the content.

Nice catch. It has been corrected.

Jul 27, 2016
...who saw gods in ancient cave paintings.
@Maggnus
maybe the cult leaders have finished their interpretations of the MYTHS you argued with the eu idiots about in this thread?
http://phys.org/n...led.html

from that thread
You are an Acolyte of the Church of the Sacred Lightning Bolt, and like a Scientologist or Radical Islamic or Fundamentalist Christian you will not listen to or accept ANY evidence that your cherished beliefs might be wrong. You use dogma and confirmation bias to support and justify your belief in the Great Electrical Pantheon while steadfastly ignoring that which does not conform and denigrating any who point it out to you.

You are as dogmatic as the worst priest or imam. And you will not understand how I can say this, because you are so steeped in your fantasy that you cannot look beyond it.

You are an Acolyte of the Electric Universe and your fanaticism will not be swayed by evidence
TRUTH

Jul 27, 2016
Ah, the Lessor Accolyte! Lets see what he preaches:
Zircon dating is a form of thermoluminescence dating.
No, it is not. So the whole rest of this illusion he is trying to set up means nothing.

Zircon dating is a form of radiometric dating. In other words, it is a method of measurement that does not require anything except the means to measure the decay of a radioactive material.

In other words, the technique makes a crucial assumption about the electrical conditions since the event occurred.
Wrong.

I need to emphasize that in electrical cosmology, there is no reason at all to accept this assumption.
That is because electrical cosmology is a pseudo-science.

Jul 27, 2016
Simple: Two objects travel through space of dramatically differing charge densities. Then, they come in close proximity.
Yes! So close, they COLLIDED!

Truthfully, the questions should be directed at yourself as to what assumptions you've failed to question which have created your own failure of imagination.
Truthfully, you should learn to question that which you are told by people with a reason to gull you. It does not require imagination to see that the Church of the Magic Lightning is ta laughable quasi-religion that is FILLED with internal inconsistencies and dogmatic, pseudo-scientific belief over evidence and observation. .

PS - thanks Stumpy!

Jul 27, 2016
It's not extraordinary in terms of the numerous astronomical observations of electricity through space which are today ignored by gravitationalists.
There are none. Glad you agree.

The very fact that gravity exhibits such difficulties doing the work that is observed should give you some pause. If it is really true, as claimed, that gravity is in some manner a side effect of electrical charge or electrical flow over plasmas, then the relative stability of G dictates that we are talking about very large amounts of charge.
IF. Of course, IT IS NOT TRUE. SO the rest of your sermon mounts to exactly: Zero.

The idea that every once in a while, the system's stability would be undermined, resulting in some discharge, is not actually extraordinary.
. You;'re right, it is quite simply not possible.
Same sort of stuff happens on transmission lines -- long periods of stability punctuated by violence.
Apples vrs Dandelions. And also imaginary.

Jul 27, 2016
Think in terms of scales: If gravity typically dominates at the interplanetary scale, and electricity dominates above that, then of course there would be situations where huge discharges can occur. The discharges might be so big, in fact, that they could literally create mountains and even shift continents in just hours over enormous distances.
And if my Aunt had balls, she would be my uncle.

"Appear" "Look like" "similar to" Other words of pseudo-science and sciency-sounding gobblegook...

To be blunt, textbook science has failed to equip us to understand such arguments. There's a lot of work left to be done.
They would equip you just fine to ask further questions, if you knew what they said. You should try reading some.

Jul 27, 2016
PS - thanks Stumpy!
you are very welcome @Maggnus

that thread is pure gold from a deviant psychopathy perspective... or a cult training session
LMFAO

i am still LMFAO about the whole "MYTH" argument

but it also brings a point to bear WRT your comment i quoted:
there is no evidence they will ever accept as legitimate so long as they perceive it to be against or undermining their religious beliefs (just like any fanatical fundie x-tian here)


Jul 27, 2016
A CORRECTION: I have commented on impactor fragments. I have to correct myself on this one - the iron 30-50 meter wide meteorite that caused this crater would have been vaporized in the impact. The vaporized remains were incorporated in the vaporized soil and bedrock from the impact site, so the fragments are tiny.

The overturned bedrock and the ejecta blanket contain iron fragments in it from the impactor, so I am more correct than incorrect, but I wanted to ensure I am not misrepresenting the facts.

I do note there was a find of a 600lb impact fragment in the 1800's, but this was probably an outlier or a piece that broke off the main impactor prior to it striking the ground.

The overturned bedrock and ejecta sheet also confirm this as an impact site, something recognized by Barringer in 1903. No magical lightning bolts necessary, thank you very much.

Jul 27, 2016
There is a much, much simpler explanation of the above wild conjecture. Electric discharge can explain these events much more concisely and it can be verified by experiments unlike the guesses above.

Except people have seen asteroids and have witnessed their entry into Earth's atmosphere, but they never saw a cosmic lightning hitting the Earth.

If you place a charge on the surface of Earth, how long does it take to dissipate or be conducted away?

Jul 27, 2016
"Zircon dating is a form of thermoluminescence dating. "

Actually, zircons are typically dated using U-Pb dating. That's why they can give the ages of rocks that crystallized 3.8 billion years ago. TL dating has upper limits in the thousands to hundreds of thousands of years only.

Zircons are also acknowledged to be very poor candidates for TL dating: very high internal dose rates (resulting in early saturation of TL signal) and anomalous fading (loss of TL signal) being just two of the many problems these minerals are plagued by.

If I was to date this crater using luminescence, I'd use the common minerals: quartz as my first choice, K-rich feldspar as second, also not TL but optical dating (aka OSL, optically stimulated luminescence).


Jul 27, 2016
"Zircon dating is a form of thermoluminescence dating. "

Actually, zircons are typically dated using U-Pb dating. That's why they can give the ages of rocks that crystallized 3.8 billion years ago. TL dating has upper limits in the thousands to hundreds of thousands of years only.
ie, Radiometric

If I was to date this crater using luminescence, I'd use the common minerals: quartz as my first choice, K-rich feldspar as second, also not TL but optical dating (aka OSL, optically stimulated luminescence).
I wouldn't use OSL either. It would give you a probable age range for the sediment the impactor struck, but I don't think it would give a good age for the shocked material or the ejecta blanket, and it would be useless for use with the zircon crystals they found at the impact site.

Jul 27, 2016
Cavosie is studying impact impact [sic] on zircons in part because he can't find any in the geological record from before 3.8 Ga, when the late bombardment is supposed to have happened.

Attempts to predict the absence of shock features are annealing during subduction, which some zircons partly survive (despite originally are being generated by it). But that would only predict part of the record, some zircons may never have been recycled through subduction again.

Re the electric universe pseudoscience, it is notable that they become the worst windbags they can be when they try to defend what they don't understand (EM theory, plasmas). That is the clear sign of incompetents. We have learned a lot by studying their antics. [ https://en.wikipe...r_effect ]

Jul 27, 2016
I wouldn't use OSL either. It would give you a probable age range for the sediment the impactor struck, but I don't think it would give a good age for the shocked material or the ejecta blanket, and it would be useless for use with the zircon crystals they found at the impact site.


Yes, as I said, zircons ARE worse than useless in luminescence dating; that's why we luminescence daters take great pains to remove them from our samples prior to analyses.

But OSL does very well on the other minerals I mentioned, whether they be heated, shocked, exposed to light, or given a combination of these. And in addition, it has several analytical and statistical advantages over TL.


Jul 27, 2016
But OSL does very well on the other minerals I mentioned, whether they be heated, shocked, exposed to light, or given a combination of these. And in addition, it has several analytical and statistical advantages over TL.
I agree, but I think maybe I am missing your point?

I think that OSL would work fine for identifying the age of the sediment layers from both before and after the impact, but I am not sure that it would be as useful for use on the ejecta blanket or impactor fragments. Do you agree, or am I misunderstanding you?

Re the electric universe pseudoscience, it is notable that they become the worst windbags they can be when they try to defend what they don't understand (EM theory, plasmas). That is the clear sign of incompetents. We have learned a lot by studying their antics. [ https://en.wikipe...r_effect ]
Yes, well said!

Jul 27, 2016
But OSL does very well on the other minerals I mentioned, whether they be heated, shocked, exposed to light, or given a combination of these. And in addition, it has several analytical and statistical advantages over TL.
I agree, but I think maybe I am missing your point?

I think that OSL would work fine for identifying the age of the sediment layers from both before and after the impact, but I am not sure that it would be as useful for use on the ejecta blanket or impactor fragments. Do you agree, or am I misunderstanding you?


*Both* the TL and OSL clocks are reset by heat, so since meteor impact causes shock heating, the shocked/heated ejecta and crater itself can be dated by both methods.

NB the excellent work below:

Sutton, S.R. (1985) Thermoluminescence measurements on shock-metamorphosed sandstone and dolomite from Meteor Crater, Arizona. 2. Thermoluminescence age of Meteor crater. Journal of Geophysical Research, v. 90, pp. 3,690-3,700.


Jul 27, 2016
*Both* the TL and OSL clocks are reset by heat, so since meteor impact causes shock heating, the shocked/heated ejecta and crater itself can be dated by both methods.

NB the excellent work below:

Sutton, S.R. (1985) Thermoluminescence measurements on shock-metamorphosed sandstone and dolomite from Meteor Crater, Arizona. 2. Thermoluminescence age of Meteor crater. Journal of Geophysical Research, v. 90, pp. 3,690-3,700.
Excellent, I will take a look. Before I do, are they coming up with similar ages as the radiometeric measurements?

Thanks Digs!

Jul 27, 2016
NB the excellent work below:

Sutton, S.R. (1985) Thermoluminescence measurements on shock-metamorphosed sandstone and dolomite from Meteor Crater, Arizona. 2. Thermoluminescence age of Meteor crater. Journal of Geophysical Research, v. 90, pp. 3,690-3,700.
@Digs
Thanks for the reference and the info above

Re the electric universe pseudoscience, it is notable that they become the worst windbags they can be when they try to defend what they don't understand (EM theory, plasmas). That is the clear sign of incompetents. We have learned a lot by studying their antics. [ https://en.wikipe...r_effect ]
100 star comment

very well said

Jul 30, 2016
I am stunned that so many people cannot accurately read a simple sentence. They are saying that a 12 kilometer asteroid could not have made the crater. READ IT! It says the asteroid was 50m in size, travelling at 12km per second, NOT a 12km asteroid. It would be one thing if it was only one person but close to half a dozen people said the same thing. Without reading comprehension, there is no point in reading.

Jul 30, 2016
I am stunned that so many people cannot accurately read a simple sentence. They are saying that a 12 kilometer asteroid could not have made the crater. READ IT! It says the asteroid was 50m in size, travelling at 12km per second, NOT a 12km asteroid. It would be one thing if it was only one person but close to half a dozen people said the same thing. Without reading comprehension, there is no point in reading.

See that part in the title where it says (Updated)? That's because they updated the article when it was pointed out to them that they had mistakenly included the comment that the impactor was a 12KM wide iron meteorite.

Jul 31, 2016
There is a much, much simpler explanation of the above wild conjecture. Electric discharge can explain these events much more concisely and it can be verified by experiments unlike the guesses above.


The simple explanation is that you are antigoracle baboon's sock puppet, and that you still can't drive, here's another one for you to add to your already towering 1s ... ;)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more