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This is an impact-triggered avalanche on Mars
It's important to preface
what I'm about to share by firstly sharing what an impact-triggered avalanche looks like.
The materials are activated by impacts and fall downhill, as if they were liquid.
1/
https://www.uahirise.org/ESP_017229_2110
It's important to preface
what I'm about to share by firstly sharing what an impact-triggered avalanche looks like.The materials are activated by impacts and fall downhill, as if they were liquid.
1/
https://www.uahirise.org/ESP_017229_2110
Here is another
We know these happen on the Lunar surface, but we haven't really identified many or any significant ones. This has confounded me for a long time, and it took studying nearly every other body in the solar system to, finally, bring those skills of investigation to our moon...
Without getting too deep into lunar science, Ilmenite is a mysterious iron and titanium-bearing oxide, which is found, especially, in the Maria (large, old craters) on the moon.
It's a key goal for lunar scientists to understand it's distribution!
It's a key goal for lunar scientists to understand it's distribution!
Now, I don't claim to understand where the Ilmenite came from, but I can tell you why many areas of the Lunar Maria have large areas where this mysterious material is missing!
Welcome to my world of Lunar impact-triggered avalanches, and how these events shape the Moon's face:
Welcome to my world of Lunar impact-triggered avalanches, and how these events shape the Moon's face:
This is a map of many Lunar impact events around 800 million years ago. This paper was published this year, and was an incredible help in solving this puzzle.
I've highlighted three impacts in yellow, and we'll be discussing these, in particular.
But firstly, I have to explain:
I've highlighted three impacts in yellow, and we'll be discussing these, in particular.
But firstly, I have to explain:
This is an impact-triggered avalanche on the moon. It's exactly what I showed you on Mars, but MUCH larger, and on the Lunar surface!
On Mars, these features appear well in infrared. On our moon, they are even more visible in ultraviolet, because of the underlying Ilmenite!
On Mars, these features appear well in infrared. On our moon, they are even more visible in ultraviolet, because of the underlying Ilmenite!
The Proclus crater, thought to be low angle (because it's ejecta seems missing on one half of it's eject blanket), actually appears this way because it's a very large impact-triggered landslide! That's why there are no ejecta rays in that area, it crumbled from the impact!
Pay close attention to the Ilmenite texture- diverse and fading from red to orange, with a gradient. Notice the abrupt interruption of this texture with these avalanches.
They absolutely contrast against the older Ilmenite. This is clearly overlain material!
They absolutely contrast against the older Ilmenite. This is clearly overlain material!
Here is the first impact-triggered avalanche I found, and what allowed me to find the others. It's massive, and caused quite a bit of the Apennine mountain range to crumble. Leaving much of it in Mare Imbrium.
It's an incredible impact-triggered avalanche, but not the largest!
It's an incredible impact-triggered avalanche, but not the largest!
The three impact-triggered avalanches I've illustrated here all fell in, apparently, the same era ( https://www.nature.com/articles/s41467-020-17115-6). They all look very similar. This gives us an incredible tool to better understand the Ilmenite distribution on the Lunar surface.
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Here's the info on the Ilmenite
It also has an interactive map to explore the Ilmenite distribution.
You could even find more impact-triggered avalanches yourself! There is a very large one, near the others, also on the 800m year old impact map!
https://www.lroc.asu.edu/posts/986
It also has an interactive map to explore the Ilmenite distribution.
You could even find more impact-triggered avalanches yourself! There is a very large one, near the others, also on the 800m year old impact map!
https://www.lroc.asu.edu/posts/986
I also didn't go into detail about how other impacts (from this 800m year meteor shower) have also covered the Ilmenite with their ejecta (appearing the same as overlain avalanche deposits).
So, it's established that new, overlain material is absent of the Ilmenite!
So, it's established that new, overlain material is absent of the Ilmenite!
