I expect the asteroid impact just happened at an inoportune time, perhaps coincident with a solar maximum cycle, declining magnetic field strength, hydrogen sulphide release, etc. Will be interesting to see the next ten years research results.

Gary 7

Ever watch a prizefight?

Rarely does one shot ever take out the other side.
(it happens, but not that often.)

Instead, it often is a combo of hits or a weaking of the one of the sides, due to punishment inflicted, that decides the victor.

I’ts a left, right, left, then uppercut that floors the big dude.

Talk about a “few” bad years…lol

Lunatik

The Journal of the Geological Society.

That’s what I get for being in a hurry

Mac Leod, N. 1996. K/T Redux. Paeobiology. 22(3) pp.311-371.

and

Mac Leod et al. 1997. The Cretaceous Tertiary Biotic Transition. Volume 154, Number 2, 1997, pp. 265-292(28)

I know these are older but the arguments are still valid and I don’t have time to look up anything newer right now gotta go to seminar.

Paul

WRT the Chicxulub story, I’m with Luke — the “mounting” evidence is really just a pile of press releases put out by Gerta Keller and her co-workers. Check the peer-reviewed science, and you’ll see they’re not getting any confirmatory studies from anybody else. The problem is that Keller & co. keep working from samples in the disturbed geology near the Chicxulub crater (where post-impact landslides and tsunamis and such make the stratigraphy pretty tangled). Nobody’s been able to find data that corroborates their take on things anywhere else.

Lorne

Phil, isn’t it obvious, there was a rapid evolutionary development after the Chicxulub impact, driving a tribe of raptors to sentience, who developed a high civilization, then went hunting for trophies. I’ll bet we discover a raptor house burried under radioactive debris from that period, with tyraunosaurus heads mounted on the walls.
“Well, dang, they were just standing there, waiting to get shot,,,”

,,,or maybe, some time travelers needed to go back and bring home some really big game,,,this is what happens when we over hunt species,,,

GAry 7

“,,,removes toungue from ear,,,”

I’m not a bad astronomer, but I’m a Stunningly Mediocre Paleontologist.

There’s two important data to keep in mind about the Keller article. The first is that the end of the Age of Dinosaurs was what you might call a “noisy” time. There was at least one, probably more, bolide impacts. There were the Deccan eruptions which were neither small nor short in nature. The Atlantic Ocean was also opening up, and with this change of sea level there were a host of related environmental changes. You could make the argument that maybe one thing or another was the crucial factor that led to the demise of the dinosaurs, but you’d be just pooh-poohing a lot of other information.

The second is Keller’s data. Notice this is NOT in the peer-reviewed literature! This is a newspaper article, and hence not held to the same standards. As far as I can tell, he could be talking about new data, or he could be talking about his old work on the subject. If it’s the former, I’d sure like to see it in Nature or Science or somewhere. If it’s the latter, I recall that there were questions about the research. While I did not read the article myself, I heard secondhand his data were taken from a single locality and he was not very forthcoming about sharing them. Keller has been dismissive of the bolide impact hypothesis for a long time, and naturally people were very curious to see what he’d got. I would treat this news report with caution and look for the published data.

On a related note, my friend and former instructor Dr. Richard Muller is giving a talk on the bolide hypothesis this week. Richard wasn’t directly involved in the Alvarez’s work, but he’s done some related work and he’s mentioned in T. Rex and the Crater of Doom, Walter Alvarez’s popular press book on the subject. If you get University of California Television or you have a big enough dish, you can check him out:

http://www.uctv.tv/schedule3.asp?summary=show&keyword=11829