Slashdot Mirror
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."
They were killed by all of the cavemen for food.
At least that's what my science teacher told me.
- A Student from Kansas
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.
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.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
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.
Kwisatz Haderach
Sell the spice to CHOAM
This Mahdi took Shaddam's Throne
That's not how it works.
Considering the vast amount of time captured in even 13 cm of strata, there are many more generations of dinosaur corpses created and sorted through the taphonomic filter than would be created by a sudden extinction event. The deposition associated with the Hell Creek is one of rivers - which means there's a lot of energy to destroy things, as well as problems transporting from death location into the river to begin with. Simply put, there is no reason to expect that you'd fine a single bone from the last generation of dinosaurs - and even if you did, you'd have a hell of a time proving it.
Here's an example paper from the modern that looks at this problem : http://www.cornellcollege.edu/geology/greenstein/personal/Reprints/Diadema.pdf
Clear record of mass mortality, like you expect, requires exceptional preservation such as that captured in the Burgess Shale. That isn't the case for the Diadema, or for the Hell Creek formation.
And yes, of course you can associate things at 13cm. The number of vast changes in flora and fauna at the K/T boundary match up as well as could be expected with the Iridium spike and other impact markers. This is strong evidence that there is an association.
Alligators are not dinosaurs, they're Crurotarsi, which are well known to deeply hate dinosaurs for playing dirty tricks on 'em back in the Triassic-Jurassic transition. So for your own sake, don't even mention dinosaurs to your pet alligator, and especially don't start an argument about it! Only thing the alligator is going to like about the argument is taste of your ripped-off limbs!