[1] https://www.pnas.org/content/early/2018/12/26/1804350116
https://www.nationalgeographic.com/science/2018/11/impact-cr...
would the erosion caused by glaciers, have enough time to erase the planet-wide evidence of that hit as well?
What conditions need to be there for the erasure to work quickly?
The number one condition for fast glacial erosion is what's called "wet-based ice": if pressure and temperature at the base of the ice sheet (warmed by geothermal heat flow) is near the melting point, then ice tends to slip against the rock and erode rapidly; if it's too cold, then the ice will flow internally instead and not erode very well. Coupled climate-icesheet models so far [2] suggest it's possible to get wet-based ice even in a "hard snowball" state with limited precipitation from sublimation alone (though not under all parts of the icesheet at once).
[1] https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/JB07... [2] https://www.sciencedirect.com/science/article/pii/S0012821X0...
1.) Could the type of wide-spread glaciation you propose be aided by clustering of continental mass at or near the poles?
2.) Is there any research into what sort of event(s) might trigger world-wide glaciation?
Apologies if it was in the article and I missed it. The notion is definitely cool. :)
Cheers, Robert
1) Perhaps counter-intuitively, it's generally thought to be easier to enter a Snowball state when most of the continents are at the equator, the reasons being (A) silicate weathering of the continents consumes CO2 and is faster at low latitudes and (B) the albedo (reflectivity) contrast between ice and water is greater than the albedo contrast between ice and land. Ice is very reflective, water is not, and land is in between. In other words, if you grow sea ice at the poles, you make Earth more reflective, and the change in light (and heat) reflected per unit area of ice cover is greater for ice grown over oceans than ice grown over land. There is some background on the history of the Snowball Earth hypothesis, including the above points about albedo, here: https://en.wikipedia.org/wiki/Snowball_Earth
2) Definitely. I don't know the right answer yet, but here's a relatively recent (and relatively accessible) Scientific American article on the topic: https://www.scientificamerican.com/article/a-new-idea-on-how...