Very interesting theory; I"d love to see more, and perhaps some of their data compiled to reach this conclusion. I'll do some searching later when I come home from work.

Thanks much!

The basics of the theory are outlined in the book, The Cycle of Cosmic Catastrophes by Firestone, Wes and Warwick-smithISBN 1-59143-061-5

Ah nuclear targeting one of favorite subjects, yes in general an airburst is the best way to maximize damage. Depends on the target, amount of hardening, the terrain, accuracy of your target data and even the weather.

At this time the Tungie blast has been assigned to a meteor or comet fragment that self destructed with 5-30 megatons of force.

The heat generated by compression of air in front of the body (ram pressure) as it travels through the atmosphere is immense and most meteoroids burn up or explode before they reach the ground.

It has been discussed before in the scientific community and I'm one of the ones who has a problem with it. The problem with it as a "source of extinction" is that not all of the species went extinct at the same time -- and some of the species that went extinct at the end of the last Ice Age were in Australia and other areas of the world.

In addition, it requires the comet to kill certain animals that are large but leave other large animals alive. For instance, it killed off the Giant Ground Sloth which was much larger than human beings ... but left bison (also larger than humans) alive.

Yes the selective killer comet - which killed of megafauna but not everywhere (Elephants survived)

The comet/asteriod was probably part of of a cocktail of events and happenings.

Originally posted by Byrd


In addition, it requires the comet to kill certain animals that are large but leave other large animals alive. For instance, it killed off the Giant Ground Sloth which was much larger than human beings ... but left bison (also larger than humans) alive.

Actually the modern bison is an asian imigrant, that replaced the giant bison after it became extinct, some 13k years ago.

Early human (clovis) also become extinct in NA and are replaced by newer asian imigrants.

Early human (clovis) also become extinct in NA and are replaced by newer asian imigrants.

Prehaps but I'd still hold that one as a maybe. The tool industry changed but that could have been a cultural shift. (from spear and spear thrower to bow and arrow.

[edit on 22/7/08 by Hanslune]

I think they are confusing two different events,I just read an article somewhere, a couple of weeks ago, and I am certain that the event that dug up the diamonds was an impact 290 mya in the canadian shield, that formed 62 mile across Manicouagan crater.
Diamonds are found and mined in the canadian shield, but they must be excavated, as diamonds are formed deep within the earth, billions of years ago. It takes something to dig them up.
I dont dispute either event, as I have mentioned in other posts, there is geological evidence for the cometary event of 13k years ago.
The ash layer that can be found throughout north america is a good one. It has been found in locations around the north american continent at the same depth(age), around 13k years ago.
This impact left no crater because it was an airburst, as has been mentioned, from thermal and physical shock loading of the stoney body.

Originally posted by punkinworks
I think they are confusing two different events,I just read an article somewhere, a couple of weeks ago, and I am certain that the event that dug up the diamonds was an impact 290 mya in the canadian shield, that formed 62 mile across Manicouagan crater.

In that case, yes, they would be confusing it.

I dont dispute either event, as I have mentioned in other posts, there is geological evidence for the cometary event of 13k years ago.

Actually, there isn't.

The ash layer that can be found throughout north america is a good one.

...but it hasn't. That's the problem. There's a "black mat" that's been found in some areas, but no layer of ash. And a layer of ash would mean that everything (from tiny mice to shrubs to the largest animals were killed.) But I haven't checked recent papers.

Nor am I convinced that the disappearance of Clovis points is a sign of extinction. The megafauna was disappearing at the same time (and thank you for correcting my dates -- the current bison appeared at the end of the last ice age) and the projectiles needed to hunt them would have to change. You can't hunt birds with a huge spear.

But the very old crater and diamonds... yes, that makes sense.

It will take about 15-20 years to complete all the work needed to clear up this picture.

At sites from santa barbara thru arizona to the carolina's and up to michigan, core samples have yielded a carbon rich layer that dates to aproximately 12,900 years ago.
This carbon layer also shows up at approxemately 50 clovis age sites, and is found in 15 sites in the carolina bays.
The cores at these sites have also contained such things as, helium3, carbon 60(fullerenes), Polycyclic aromatic hydrocarbons (a chemical signature of wildfires) magnetic grains containing iridium, and magnetic micro-shpereules.
Helium 3 is very rare on earth, and iridium is extremely rare, carbon 60 is only found on earth in soot, and has been found in extra terrrestrial objects(carbonaceous condrites).
The hypothosis puts the break up of the object over canda as it travelled from the nw to the se.
It also happens that the sites with the greatest concentration of celestial material are in michigan just south of the previous edge of the glaciers.

If the object broke up into a shower of tunguska type events, over the ice sheet there would be no large crater, Thr crater would have formed in the ice and subsequently disappeared.
There are three extremely deep round structures in the great lakes, that have recently been discovered, that could be the craters every one is looking for. There is also a newly discovered structure on the edge of Hudson bay that has indications of a crater wall.
And any crater on land that formed that far north would have been scoured away, for the most part, by the resurgent glaciation that followed.