Stony-iron Meteorites: An Introduction
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- Опубліковано 14 гру 2021
- UCLA Meteorite Gallery Lecture Series - December 2021
Title: Stony-iron Meteorites: An Introduction
Lecturer: Dr. Alan Rubin; UCLA
There are two main kinds of stony-irons: pallasites and mesosiderites. Pallasites consist of roughly half metallic Fe-Ni and half magnesian olivine; these rocks were derived from the core-mantle boundaries of differentiated asteroids. Most pallasites belong to the main group (PMG) and are related to HED samples and IIIAB iron meteorites. Five pallasites belong to the Eagle Station (PES) group; these rocks are from differentiated carbonaceous-chondrite-like
asteroids. Their olivine grains are more ferroan than those of PMG (Fa20 vs. Fa12). There are also a few pyroxene pallasites that contain more pyroxene than PMG or PES and have distinct O-isotopic compositions.
Mesosiderites contain approximately half silicate and half metallic Fe-Ni, but the silicate in these rocks is mainly basaltic with relatively little olivine. Mesosiderites are impact breccias, probably formed by the collision of a largely molten metallic core with the basaltic crust of another differentiated asteroid. This occurred early in Solar-System history.
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A fantastic presentation
Incredibly rich and informative video absolutely loved every minute of it. 👍🏻✅
Thank you for this great content!
Very helpful and educational great efforts my brother✨
I like this video 😍 Thanks you 💕 Great 👍 meteorite
Great video. seems to be pretty comprehensive of the given topic. I especially appreciate the inclusion of open mysteries like the missing olivine from mesosiderites and I agree that the metallic impactor hypothesis seems plausible but I wonder what the cooling rate would be of a naked core. those bodies would have to be in fairly close proximity. One thing I would like to know more about is variation of impact energies and the effects in relation to melting and mixing therein.
Asombroso 🤩
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Why was the New England Meteorite Lab result for my rocks was not a meteorite when it contents white metal grains and colored metal grains. It contents a lot of metals and ruby gemstones. Of course I sent them 2 tiny rocks without grains in it because it is in their instructions to send a sample as little as a marble. I've watched a lot of earth rocks videos, but I don't see a rock like mine. In fact some of the white metal grains have widmanstatten pattern.
If a pallasite is metal with crystal, what would a Meteorite be called if it had stone swapped for the metal, so still had big olivine crystals but in a stone matrix, or has one not been found?
Interesting talk I love it I have a small iron meteorite with a piece of iron fused to it in that piece there is what looks like roots with soil or something like fabric nothing I have ever seen in a meteorite they are visible with the naked eye you can hold them with your fingers I think this could be the most important find ever tell me what you think
Alan, I'm selling a METEORITE..
You are from
A fantastic talk, but a couple questions . . .
1) Are there any meteorites that contain bits of iron with a composition suggesting they were sourced from a collision involving an earlier differentiated asteroid while it was still molten, or otherwise?
2) Is there evidence for ductility contrast or metallic ductile deformation around silicate minerals resulting from the collisions that broke or tore apart differentiated asteroids to form iron and stony iron meteoroids? Or is the metallic component brittle under those conditions?
Thank you
Hi @Martino Cole, we will get back to you with the answers to this question. Thank you!
1. The metal in mesosiderites appears to have been molten when it was
introduced into the silicate crust of the target parent asteroid. We
know this because the metal nodules have a bulk IIIAB composition, but
there is little compositional variation among nodules.
2. Metal-sulfide is the lowest melting phase in chondrites, so
generally, collisions will cause local concentrations of metal and
sulfide to melt and flow, forming veins.
Vaca Muerta is a very large Meteorite. Does every piece that's found represent an A1? I assume the answer is yes.
I'm having trouble with the reasoning there are so many subtypes of the same type of Meteorite when only 2 asteroids collided.
All I can think of is that the surface that collided face to face would of had more recrystallation and areas of the asteroid farther away from the impact surface had less.
For instance the area of the asteroid that broke up closest to the surface that impacted would be the rarest type because less volume of the asteroids took the most of the brunt from impact where as the back end of the asteroid had maintained angular clasts and metal that is more disperse because it was the part farthest from the surface that impacted . And Inbetween was moderately recrystallized.
As the asteroids broke up in many pieces would this explain why there are multiple subtypes?
The most commonly discussed model for mesosiderite formation is that
the metal and an overlying thin silicate-mantle veneer of a projectile
collides with the basaltic surface of a larger target asteroid at low
relative velocity. Type-1 mesosiderites formed after this impact, Vaca
Muerta among them. It was during subsequent smaller-scale impacts that
the mesosiderites were metamorphosed and recrystallized. Although it
is possible that parts of Vaca Muerta vary in metamorphic grade and in
the proportions of orthopyroxene and tridymite, the bulk of the
mesosiderite is A1. We cannot extrapolate further about an individual
mesosiderite containing different portions of the projectile.
I watched it twice in a row.
edit: three times
I know a gal that has two iron meteorites that she might consider selling. Who buys them and how much are they worth?
I think it looks like this
Pelletie meteorite for sell 5kg .
I believe I have the cores to prove this theory
I think, i have pallasite.
Achei um meteorito muito lindo e quero vender
Sou do Brasil
Hi master
Kam ca gure keni mundesi te me tregoni ju lutem se me duken si meteorite .
🤔
I have more meteorite +100kg
The core of any celestial body is extremely rich in platinum group metals and gold. Enough with the ppm theory. Iron and nickel aren't heavy enough to concentrate in the center. Palladium is one of the main metals in the core.
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