Did Comets Cause Ancient American Extinctions?

National Geographic News ^ | 5-6-2008 | Anne Casselman

[blam]

GGG Ping.
(I don't see much difference in this and earlier articles)(?)

[mgstarr]

I scan headlines on here and 9 times out of 10 I can tell which are your threads.

They tend to be the more cogent and interesting.

Thank you.

[EGPWS]

Did Comets Cause Ancient American Extinctions?

No.

A most likely cause was an ancient and earth minded ancestor of Albert Gore.

[DBrow]

“”You have to ask what kind of blast might peter out by the time it gets to Mexico and not have much effect on South America,”

Well, for one thing, an explosion’s force falls off as the cube of the distance (not the square) so the difference between Michigan and Michoacan could be considerable.

Tunguska flattened square miles when it hit yet Petrograd was unscathed.

[blam]

I agree.

I think it is interesting that not one Clovis Point has been found to have been made after this event.

[buck jarret]

Perhaps the megafaunas turned gay and lesbian.

[goron]

At lease Noah saw it coming and found a solution.

Who here has built an arc; or would we need just some good flood insurance, like these folks had?

http://afp.google.com/article/ALeqM5if9UIMmRHGQXvC7kXfFeM6rzUr_w

A comet hits the earth, and there would be at least 40 days and nights of cyclones and hurricanes!

[redstateconfidential]

[Eye On The Left]

I've used this graph on occasion to show people that Al Gore's CO2-temperature correlation is really a REVERSED one. Because one can clearly see that temperature increases (blue line) actually PRECEEDED CO2 increases (red line) all throughout this 400,000 year time interval. In fact, by an of average 800 years! Yet Gore makes the dishonest claim that it was CO2 that warmed the earth to get us out these past 4 glaciations (roughly every 100,000, the result of periodic changes in Earth's orbit and spin axis). BP = before present.

In any case, perhaps this same graph can be of use in this current discussion?

[VOA]

bump

[Eye On The Left]

On second thought, the graph really isn’t that useful, even when zoomed 200%. I had hoped the sharp post ice age temp decrease (at ~13,000 yrs) might show up on it.

[montag813]

An Obama Presidency would be a good time for another comet strike.

[JasonC]

No.

Next idiotic brainstorm, please.

[TXnMA]

He and his colleagues have also found widespread and abundant minuscule diamonds and magnetic particles in the layer of Earth that dates to this time.

I agree that we archaeologists are missing much vital information when we simply screen the dirt to isolate (artifacts or whatever) and then toss that soil back in the hole without examining it with every possible analytical tool.

Of course, there is that ever-present limitation of cost... :-(

[CurlyDave]

Possibly NASA could arrange for a comet to hit Al Gore.

The classic two birds with one stone.

[Caramelgal]

I think it is interesting that not one Clovis Point has been found to have been made after this event.

I watched a program about this just the other night on one of the science related channels.

I was fascinated to learn that there are more Clovis period settlements and Clovis spear points discovered along the Delmarva peninsular (Chesapeake Bay regions of Maryland and Virginia) than found in all of the entire SW and no evidence of any Clovis activity in the Delmarva after the Younger Dryas.

Also Clovis type spear points are not found on the Siberian side of the Bearing Straights. A much different technology and materials were used (on the Siberian side spear points are made of bone with sharp flint inserts vs. Clovis points made entirely of flint with channels carved for insertion into spears) so that would lend some credence to one theory that Clovis points were developed after a Bearing Straights – Asian migration or…as some spear points with a very similar to design and materials to Clovis points have been discovered in France that date to or date somewhat before the earliest Eastern Clovis settlements, there is a theory that says there were two separate migrations, one from Europe via an Atlantic crossing that were the Clovis and the other across the land bridge and that the Younger Dryas forced the Eastern Clovis culture to migrate West and perhaps melding with and into the Asian immigrant culture.

[TXnMA]

I think it is interesting that not one Clovis Point has been found to have been made after this event.

I'll have to ask Mike Collins (the Gault Site) about that one...

[yefragetuwrabrumuy]

Whatever it was, I suspect that its effects were just as pronounced in South America, possibly wiping out either an ancient Egyptian quality civilization, or the last of the giant “terror birds”, very large, predatory birds that might have existed as late as 15,000 years ago. Or both, as they might have co-existed.

When Indians later occupied the area, they had no idea who built the great cities there.

[ProtectOurFreedom]

One widely accepted hypothesis suggests that melting ice sheets and glacial lakes 12,000 years ago dumped so much meltwater into the oceans that it disrupted ocean circulation. This in turn cooled much of the planet, especially in the Northern Hemisphere.

Sounds like an AGW kook theory to me. Global warming melted the glaciers which then caused global cooling. Somehow I have a hard time buying into the warming causes cooling theory.