Re: Study: Dinosaurs Died Within Hours After Asteroid Hit Earth 65 Million Years Ago

From: R.Schenck (nygdan_morteauxspam_at_yahoo.com)
Date: 06/25/04 

Date: 25 Jun 2004 07:03:07 -0700

baalke@earthlink.net (Ron) wrote in message news:<d5786437.0405251103.1ce85240@posting.google.com>...
> http://www.colorado.edu/news/releases/2004/168.html
>
> Study: Dinosaurs Died Within Hours After Asteroid Hit Earth 65 Million Years Ago
> University of Colorado at Boulder
> May 24, 2004
>
> According to new research led by a University of Colorado at Boulder
> geophysicist, a giant asteroid that hit the coast of Mexico 65 million
> years ago probably incinerated all the large dinosaurs that were alive at
> the time in only a few hours, and only those organisms already sheltered
> in burrows or in water were left alive.

Ah, so thats why nessie is still around.
>
> The six-mile-in-diameter asteroid is thought to have hit Chicxulub in the
> Yucatan, striking with the energy of 100 million megatons of TNT, said
> chief author and Researcher Doug Robertson of the department of
> geological sciences and the Cooperative Institute for Research in
> Environmental Sciences. The "heat pulse" caused by re-entering ejected
> matter would have reached around the globe, igniting fires and burning up
> all terrestrial organisms not sheltered in burrows or in water, he said.

I guess the crown group of birds must've had a fossorial ancestor.

snip

> The evidence of terrestrial ruin is compelling, said Robertson, noting
> that tiny spheres of melted rock are found in the Cretaceous-Tertiary, or
> KT, boundary around the globe. The spheres in the clay are remnants of
> the rocky masses that were vaporized and ejected into sub-orbital
> trajectories by the impact.

Shocked quartz no? But this is not an artefact of re-entry is it?
>
> A nearly worldwide clay layer laced with soot and extra-terrestrial
> iridium also records the impact and global firestorm that followed the
> impact.

But that's not evidence of re-entry either. They're both evidence of
global dispersal, which may be a result of orbit followed by re-entry
tho. But the shocked quartz isn't shocked by the re-entry process.
And the iridium is evidence of an impact, but hasn't got anything to
do with 'global firestorms'.

>
> The spheres, the heat pulse and the soot all have been known for some
> time, but their implications for survival of organisms on land have not
> been explained well, said Robertson.

Did they have some minimum estimate for the amount of material
re-entering, based on estimates of whats actually preserved?

> Many scientists have been curious
> about how any animal species such as primitive birds, mammals and
> amphibians managed to survive the global disaster that killed off all the
> existing dinosaurs.
>
> Robertson and colleagues have provided a new hypothesis for the
> differential pattern of survival among land vertebrates at the end of the
> Cretaceous. They have focused on the question of which groups of
> vertebrates were likely to have been sheltered underground or underwater
> at the time of the impact.
>
> Their answer closely matches the observed patterns of survival.
> Pterosaurs and non-avian dinosaurs had no obvious adaptations for
> burrowing or swimming and became extinct. In contrast, the vertebrates
> that could burrow in holes or shelter in water -- mammals, birds,
> crocodilians, snakes, lizards, turtles and amphibians -- for the most
> part survived.

Birds? In nest's made out of kindling or inside trees? If a dinosaur
is roasted by this heat, then a tree certainly is. And what about
things like mircoraptor?

Well, at least they said they restricted the study to a consideration
of land animals and didn't want to get into what happened in the seas.
 I would think tho that anything baking the continents must've had a
dramatic effect on creatures living near the surface of the oceans.
Especially planktons and forams and the like.