Paper on Comet/Asteroid Impact Causing the Younger Dryas Cooling.

[Anomalocaris]

http://www.scribd.com/fullscreen/1423991...8cpxhhn8wm

We present detailed geochemical and morphological analyses of nearly 700 spherules from 18 sites in support of a major cosmic impact at the onset of the Younger Dryas episode (12.8ka). The impact distributed 10 million tonnes of meltedspherules over 50 million square kilometers on four continents. Origins of the spherules by volcanism, anthropogenesis,authigenesis, lightning, and meteoritic ablation are rejected ongeochemical and morphological grounds. The spherules closelyresemble known impact materials derived from surficial sediments melted at temperatures 2,200 °C. The spherules corre-late with abundances of associated melt-glass, nanodiamonds,carbon spherules, aciniform carbon, charcoal, and iridium.

The area covered by the supposedly impact derived spherules would be called a "strewn field".

Normally strewn field is associated with physical impact with the ground. ie where is the crater?

It is possible to imagine an object disintegrating in the atmosphere and making a strewn field of its own smithereens without ever actually hitting the ground in big blocks to make craters.

The problem is simulation seem to show the size of the strewn field described is not consistent with an object small enough to disintegrate during passage through the atmosphere. The atmosphere would have to be dozens of times denser than it actually is to cause any bolide large enough to make such a strew field disintegrate before hitting the ground. In earth atmosphere, such an object would be expected to survive intact until it hits the ground to make a crater several miles across.

So where is the crater?

It is of course possible a crater was actually made but remains undiscovered. However, the pattern of the strewn field from so recent an impact should be well preserved and should allow one to pin point where the undiscovered crater should be found.

So the theory provides a falsifiable prediction. Let's see who is going to try to test it.