A Thermal Airburst Impact Structure

Mark Boslough's super computer generated, comet airburst simulation is a must see.In it we see the exploding comet detonating high in the atmosphere, and becoming a supersonic down draft of thermal impact plasma hotter than the surface of the sun. But watch the sequence closely. And pay particular attention to the post impact updraft at the center of the flow. And to the directions of flow of the airburst vortex at the surface, as the impact plume develops at the center of the vortex. You might want to replay it a few times.


The old way of imagining of those things was to think of it as a point explosion high in the atmosphere. And it's still popular in the press to pretend the atmosphere dissipates the blast. As you can see, it doesn't. Using super computers has allowed them to retain the downward momentum. So we can see the impact vortex hit the ground as a supersonic blast hotter than the surface of the sun. It would be naive to a fault to think such energies can be dissipated without significant planetary scarring, or ablative geomorphology.

And, in fact, in central Mexico, the recent marks of thermal airburst down blasts are terribly common. Forensically speaking there are thousands of square miles of pristine blast effected materials in central Mexico that describe the fall of a super cluster of too many air bursting fragments like the one Dr Boslough's simulation shows, and even larger, to count.

I've chosen an ordinary-typical example of what a geo-ablative airburst does when the fragment is among the last to fall in a super cluster hundreds of miles wide, lat 29.702168 lon - 105.686617:

The white line in the image is 5 miles long.

The mountain, and others like it, are the central uplift of an airburst impact structure that is different from anything ever described before. As you can see, the radial, outwards flowing ejecta curtain is almost perfectly pristine, exposed on the surface. There is no question but that the mountain is the source location of the materials in the ejecta curtain. But the mountain consists of uplifted meta sedimentary strata. It's not a volcanic vent, or rift. There is no crater here either.

The picture begins to make since when we realize that the mountain, and its pristine ejecta curtain is only a few thousand years old.

This ejecta curtain of geo-ablative melt was blown outwards by the impact down-blast. These are the patterns of movement you see when a fluid is driven across a surface by high velocity atmospheric pressure like the froth on a stormy beach.

The indication of the speed of the materials in the emplacement of the ejecta curtain is the outwards pointing chevrons.

The shocker here, is that the mountain did not exist in any form at all at the moment of impact. To really understand the process that formed the uplift, we need to look closely at the ablative patterns in its outer surface.

In the simulation, note the supersonic upwards flow in the center of post impact vortices. The mountain was born almost in an instant as the surface rebounded up into the impact vortex. So, at the same time the material in the radial ejecta curtain was being ablated, and blown outwards, the rebounding surface at the center was ablated, and pulled up into the impact plume by the upwards flow at the center of the vortex.

And the signature of that ablative upwards flow is in the deep V shaped excavations that are wider at the top, and center of the flow.

There are well over 50,000 square miles of geo-ablative terrains like this in central Mexico alone. And the region is unique on the surface of the Earth. The Arid climate has preserved the blast effected materials in context, and in perfect condition. Most of it is in almost the same condition as it was the first year after the impact storm.

These kind of strange, and surreal geo-ablative terrains can also be found in other parts of the world. But everywhere else on Earth the geo-ablative ejecta has decomposed to become soils. And the patterns of movement, and flow, in the emplacement event are no longer legible. So the melt has become indistinguishable from ordinary volcanic tuff.

This is where the fledgling science of Fluid Mechanics comes into its own, and takes flight. The ability to read the fluid emplacement motions of all of the blast effected materials of such an event with such confidence, and in such detail, makes it a kind of written language, or choreographic dance chart.

The blast effected materials of the Mexican impact zone can be thought of as a kind of cipher key, or 'Rosetta Stone', for learning to read the empirically true, geo-history of the world from the rocks themselves. And those truths can be tested.