"a supernova...is primarily responsible for melting us out of the last ice age."
While there is evidence for the supernova, it seems that either separately or in conjunction, some kind of boloid event also took place. I wonder if it could have been Tungusku-like in nature?
To quote from the article: "...large quentities of micrometeorite-like particles appear to be concentrated near the boundary between the B and C sediment horizons. They can be separated with a magnet and are identified by the presence of chondrules and by visual evidence of sintering and partial melting. These particles, dissimilar to common magnetites, are found in association with a high frequency of 'spherules.'"
Also, "Microscopic examination of chert artifacts from several widely separated Paleoindian locations in North America revealed a high density of entrance wounds and particles at depths that are evidence of high-velocity particle bombardment. Chondrules were identified visually; their presence necessarily indicates heating during high-speed entry into the atmosphere. The depth of penetration into the artifacts implies that the particles entered with substantial energy. Field simulations with control cherts for large particles (100-200 microns) suggest an entrance velocity greater than 0.4 km/second....Similar features are not observed in later-period prehistoric artifacts or in bedrock chert sources."
In summary, "Track and particle date...suggest that the total track volume...is highest at the Michigan, Illinois, and Indiana sites and decreases in all directions from this region, consistent with a widespread catastrophe concentrated over the Great Lakes region. The nearly verticle direction of the tracks left by particle impacts at most sites suggests they came from a distant source."
If the timing is right, this might explain findings of great masses of shredded animals in the far northern hemisphere, and flash frozen mammoths with undigested buttercups in their stomacks in Siberia.
Perhaps someone with a better dictionary than mine could define words like chondrule, sintering, spherules. I think these might refer to shocked quartz which is specific to boloid events.
Maybe the spaceship argument?
Serious how would they explain the existence of Mega Fauna (though seriously downsized) on Wrangell Is. and the California Channel Is. many Milena after they had disappeared on the continents?
are these "spherules" similar to the ones they've identified on Mars?
Well, it will be an interesting debate, intellectually stimulating. A bolide shower of micrometeorite sphericules as in the tunguka event of 1908 would not leave a pattern of only vertical impacts, more of a spray instead; whereas the shock wave from a supernova would do just that. Recently the magnetosphere/ionosphere was hammered down into the stratosphere by a distant energy burst so these events are more common than rare : it's a violent universe out there, amazing that we've lasted this long. Example : the indonesian super volcano that produced a nuclear winter for 3 years 74,000 years ago, almost wiping out our homo sapien ancestors. We see this in the mitochondrial DNA record : only a few hundred individuals survived out of what must have been a much larger population. Science, not theologians, opens the book on many of these mysteries.