New "Last Dinosaur" Find Backs Asteroid Extinction

An anonymous reader writes "A new fossil discovery has suggested that dinosaurs were alive right up until the asteroid impact, and did not go extinct gradually due to climate change or changes in sea level, as previous theories have proposed."

Comments

Nonsense!

[Anonymous Coward]

They were killed by all of the cavemen for food.

At least that's what my science teacher told me.

- A Student from Kansas

Re:Nonsense!

[CajunArson]

You religious wingnut! Everyone knows the Dinosaurs went extinct because climate change caused by the the Bush Tax Cuts and Big Oil!

        - A Student from San Francisco

Re:Nonsense!

[alexo]

It rained 1 day of "heavy water" which killed the water dwellers, followed by 39 days of "light water" which drowned everything else. Then, about 99% of the heavy water miraculously disappeared (or changed into light water) leaving us with the current 3600:1 light/heavy ratio.

Close, but not quite.

It actually rained super-heavy water (Tritium Oxide) and not "plain" heavy water (Deuterium Oxide), which killed the water-dwelling dinosaurs via internal beta emission. while being largely ineffective against land-dwelling creatures due to its short biological half-life (7-14 days).

Also, need for miraculous disappearance since, while Deuterium is stable, Tritium has a half-life of about 4,500 days.

Science. It works, bitches!

No, it doesn't

[Wyatt Earp]

The margin of error on when the last dinosaurs were existent and the margin of error on when the K-T boundary was deposited are both hundreds of thousands of years.

In some places there are at least 300,000 years of sediment between the fossil evidence of the Cretaceous–Tertiary extinction event and the K-T boundary.

K-T boundary has is dated to (65.5 ± 0.3) Ma, the Cretaceous–Tertiary extinction event is dated to 65.5 Ma, so the impact could have been the day the last dinosaurs were alive, it could have been 300,000 years before, 11 years after, or 213,417 years after.

Re:No, it doesn't

[thoromyr]

what I got from reading the article was that the author had a conclusion that wasn't supported by the evidence. Taking the finding at face value, a solitary find that is significantly closer than expected to the estimated time of impact would tend to support a gradual extinction. If the extinction were sudden, due to the asteroid impact, then a wealth of fossil data would be expected all the way up to the estimated time of impact, with very little (quickly going to none) following it. Instead there is (apparently, and this is information provided and agreed on by the article) a significant gap with -- to date -- a single fossil found in the region.

As far as I can tell it is another data point of no particular significance. To "disprove" gradual extinction before the impact a number of fossils representing normal population levels and distributions needs to be found.

huh?

[vlm]

We collected rock samples above and below the horn to determine the exact placement of the K/T boundary, and were surprised to see that the horn was no more than 13 cm below it.

A new fossil discovery has suggested that dinosaurs were alive right up until the asteroid impact

Speaking as a guy living in a county where the only non-service blue collar jobs left are at the local rock quarry, and having a geologist as a roommate two decades ago, I speak with profound scientific authority that those two quotes only go together if you define "right up until" as being about one zillion years. I suspect most readers define "right up until" on a somewhat shorter scale, like the time difference between the local news and american-idle, not zillions of years. (waves rolled up newspaper) Naughty journalist! Naughty!

"right up until" 13 cm of rock.

I am completely unaware of any political or cultural reason for the authors to be blind to this problem. I have no dog in the fight that I'm aware of. Just saying 13 cm of rock is not "right up until"

It MIGHT be that the real story is on a "bones per cm" basis this raises the curve implying the rate does not "tail off" (get it? dinosaur tail?) until the boundary, but that's not how the journalists are reporting it, as if the tip of the fossil was touching the boundary or chemical analysis of the fossil shows the dinosaur died during the boundary event.

extinctions

[jollyreaper]

The thing that I always wondered about with the asteroid impact theory is that we have several species of large reptiles that survived the extinction event. While I'm no scientist, I'm wondering if there might not have been some form of communicable disease that was stressing the dinosaur population beforehand that accounts for the gradual diminishing of fossils in the record and the asteroid impact might have been a coup de grace. I find it hard to imagine that sea turtles and crocadillians would survive while various marine reptiles did not -- moasaurs, plesiosaurs, icthyosaurs, etc. I suppose there will be no easy answers.