Ok, So The Definitive Answer

[tracer]

it was that meteor-thingee...

My link

p.s. - i just wish in a way that somebody hadn't come up with the name "chixulub", cause it reminds me of some of the almost calamitous dating episodes of yore, but anyway.

also, i personally would much rather be a geophysicist than a sedimentologist, regardless of what those people might actually do, just because geophysicist sounds cool. i'm very tempted to just start telling people i'm a geophysicist from now on. what would i have to know or do for that not to be a complete and utter lie? and do i need some sort of a fake badge made from a rock or sompin?

[Phoenixflood]

"Dude, you got KT'd!" from http://www.cafepress.com/trilobite.232767978

[Angus Stydens]

I came across this article today and thought I would share it with everyone. I think there are still some unanswered questions and that this is not the final word on dinosaur extinction. It may have been a last nail in the coffin, but not "the single explanation" for the great extinction. Take a minute to read it and see what you think.

http://news.bbc.co.uk/2/hi/science/nature/8550504.stm

EDIT: Merged for continuity.

[non-remanié]

As a layman reading some of Gerta Keller's papers, I just did not see the statistical significance that she was claiming to show as evidence for her deccan traps theory. She was claiming evidence for the gradual decline was clear, yet all I could see in her best hand-picked data sets were minor fluctuations that could easily be products of the discontinuous and incomplete fossil record. I have no idea what may be the problem with her stratigraphy, but I am not surprised by this result.

[Cameron DVPS]

http://news.bbc.co.uk/2/hi/science/nature/8550504.stm

EDIT: Merged for continuity

[Fossilcollector]

Sigh... I wouldn't call it confirmed; its more like a bunch of people who's careers are based on the single-impact theory agreeing with each other that they're right.

When you've actually been in the field in Mexico digging out a 30 ft section of marine life between the first impact layer and the KT iridium layer itself, you realize there's definitely something going on aside from one impact. There's 300,000 years of life that recovers between the first impact and final extinction.

-YvW

[Nicholas]

Sigh... I wouldn't call it confirmed; its more like a bunch of people who's careers are based on the single-impact theory agreeing with each other that they're right.

I agree with this.

The same thing happened with Ida, it was held in a lab and tested on only by limited hands. It turned out to be significant for the wrong reasons. This also happened the "dino dance floor" incident where a few specialists were convinced and published papers on the footprints and once it was peer reviewed it was found out to be completely natural and not fossil in nature.

[TygerTyger]

Why does there have to be a single explanation anyway?

[Fossilcollector]

There were many things that the Science article group and single-impact theorists essentially ignored or decided to explain away as misinterpretation.

For example:

At the outcrops in northern Mexico, between the lowest impact spherule and the KT iridium layer are 30 feet of organic rich marine marls, several eroded spherule layers, a limestone layer, and the "tsunami" sandstone layer.

The single-impact people explain this as all happening within hours of the impact...

They explain that the limestone layer was actually a landslide of a single limestone layer from elsewhere... The major problem with this is that the limestone layer is continous in outcrops for 170 miles; its not a limestone breccia or conglomerate that would indicate an underwater landslide, its a single deposit of layered limestone. Another problem is that there are trace fossil burrows within the limestone that are actually lined with eroded spherules...

That's just one of the various issues about the single-impact theory thats being ignored.

-YvW

[siteseer]

There were many things that the Science article group and single-impact theorists essentially ignored or decided to explain away as misinterpretation.

For example:

At the outcrops in northern Mexico, between the lowest impact spherule and the KT iridium layer are 30 feet of organic rich marine marls, several eroded spherule layers, a limestone layer, and the "tsunami" sandstone layer.

The single-impact people explain this as all happening within hours of the impact...

They explain that the limestone layer was actually a landslide of a single limestone layer from elsewhere... The major problem with this is that the limestone layer is continous in outcrops for 170 miles; its not a limestone breccia or conglomerate that would indicate an underwater landslide, its a single deposit of layered limestone. Another problem is that there are trace fossil burrows within the limestone that are actually lined with eroded spherules...

That's just one of the various issues about the single-impact theory thats being ignored.

-YvW

That's interesting. There was a Discovery Channel show a few years ago that discussed the double-impact theory with Gerta Keller as its spokesperson. It was one of maybe two shows that talked about the proposed "tsunami layer." When I think about modern tsunamis, the immediate effects are all too evident, but wouldn't evidence of them in prehistory be extremely rare - a geologic nannosecond-long event erased by even slight erosion in the area in nearly all cases?

Edited March 15, 2010 by siteseer

[Auspex]

I cannot cite the study, because I don't remember where I read about it, but there is a theory that the Chixulub impactor was just one of three or so (from the same fragmented space rock) that struck around the globe that day as the Earth rotated.

[Boesse]

*If* you read that article and felt anything in the vicinity of convinced, then read this: http://in-terra-veritas.blogspot.com/2010/03/41-angry-scientists.html

Anyway, the thing I don't like is the use in this case of the argument of authority - "oh, there's 41 authors on our paper, and we all agree, so it's official" - I'm sorry, the press is passing this off like a "panel of experts" sat down and issued a ruling on the subject, which is simply a bunch of bull.

Bobby

[LanceH]

Abundance of evidence for one theory does not actually prove a theory. It could just mean more of that evidence has been collected and studied. Theories and conventional thinking come and go.

[jkfoam]

The meteor impact was, I believe the icing on the cake so to speak. Concurrently there was extreme volcanic activity at the time which was contributing to specie stress. I believe that the combination of the two phenomenum lead to the massive KT extinctions.

JKFoam