News on what started snowball Earth

https://phys.org/news/2019-09-giant-asteroid-ancient-ice-age.html

So debris from an asteroid clouded up Earth, lowering solar heating and that seems to be what started snowball Earth a half billion years ago.

maybe a naive question, but if the asteriod hit Earth and that created the asteroid dust, wouldn't it be indistinguishable from space dust produced from an extraterrestrial asteriod explosion?

@wildgrass said
maybe a naive question, but if the asteriod hit Earth and that created the asteroid dust, wouldn't it be indistinguishable from space dust produced from an extraterrestrial asteriod explosion?

I imagine the ejecta from an Earth impact would largely consist of local rock with the material from the actual impactor being buried. So the chemical makeup of the dust should be a smoking gun.

@DeepThought
Besides, it sounded like the report was suggesting the cloud was in some kind of orbit above the atmosphere and long lived enough to seriously lower radiance from Sol.
When an asteroid hits, it certainly can block sunlight but not for more than a few years, not enough to run Earth into snowball Earth.
It sounds to me like the solar blockage was enough to kick start a snowball Earth but when that covered most of the planet the ice was reflective enough to maintain that ice layer for a hundred million years or so in spite of the fact the dust cloud could never last a thousands of that period of time before it would dissipate but by that time Snowball Earth was a near permanent thing lasting for millions of years because the ice was so reflective.

@deepthought said
I imagine the ejecta from an Earth impact would largely consist of local rock with the material from the actual impactor being buried. So the chemical makeup of the dust should be a smoking gun.

Again, very naively, wouldn't the local rock have been there regardless? If the space dust was made of earth then it wouldn't rightly be from space.

@wildgrass
Well the suspected impact of a Mars size planet and Earth produced Luna but would have covered the whole planet with so much dust pretty much zero sunlight would have gotten through.
So a couple of asteroids crashing a few hundred miles above Earth would have left a very large dust cloud which would have covered up the sun also.

@wildgrass said
Again, very naively, wouldn't the local rock have been there regardless? If the space dust was made of earth then it wouldn't rightly be from space.

Well, it's undergone a lot of heating, so the material will be different from whatever the non-impact derived terrestrial granules look like. The article seemed to indicate that the granules were found away from the impact site. So it should be possible to differentiate impact debris from terrestrial material from other sources and from asteroid derived granules.

I am guessing though, this needs a geologist.

@DeepThought
Well, about finding debris away from the impact site, the Chicxulub impact spread debris now found 700 feet thick in BURMUDA! That was a BIG boom.....