[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Dinosaur Extinction: Impact vs Volcanoes

Hi All,

Just thought I'd mention that there's been an intriguing programme on TV here
in the UK tonight, on our Channel 4...

The science program EQUINOX ran a special ("Killer Earth") about a new theory
being proposed to explain the mass extinction suffered by the dinosaurs, 65m
yrs ago. All on the List will be aware, I'm sure, that the fave theory is that
a massive asteroid / comet impacted the Earth off the Yucatan peninsula,
making a helluva mess and triggering a distinctly dinosaur-unfriendly nuclear
winter... 

A new theory being proposed, and being taken very seriously, is that the
impact happened when the mass extinction was already well underway, many
species had already been made extinct, and the culprit was volcanism on a
MASSIVE scale. Apparently "basalt floods" can flood tens of thousands of
square miles with very fluid, fast-flowing lava, triggering fires, causing
massive air pollution... and geologic records show that a basalt flood was
already in progress - and covering more than half of India - when the
"dinosaur killer" struck. And, apparently, there's lots of evidence to link
other mass extinctions - especially the most terrible of all ME's, 250m years
ago - with basalt floods. 

It was a fascinating programme, very well produced, filmed and written, and
made a very good argument. If I can track down a  website for the program I'll
pass it on. In the meantime, does anyone on the List have any info about /
opinions on this alternative theory..? (Ron? Can you hear me?) Could these
massive lava eruptions have created tektites?

... and talking of "killer impacts"...

I'll share an embarassing story with you, if you promise not to laugh. I was
co-presenting an astronomy lecture last evening, and at the end of the talk I
invited everyone around to look at my (humble) meteorite collection, passing
around my well-handled Canyon Diablo fragment and Gibeon slice etc... everyone
seemed very impressed, and I only had to explain SIX times how we know that
*that* dust comes from a rock blasted off the planet Mars... !

At the end, someone asked me if a falling meteorite would "do much damage"...
so, holding up my good-sized chunk of Sikhote Alin,  I asked him to imagine
how much "damage" it would do if it hit him on the head after tearing through
the atmosphere. I moved to hand him it, telling him to feel the weight... 

...and I *dropped* it... from some height... onto an empty pint glass standing
on the table below. There was a terrible sound of shattering glass, and clear
slivers scattered everywhere, leaving my poor SiAl lying there surrounded by
sparkling glass shards... 

As Homer would say... "DOH!!!"

Well, despite my desperate prayers the ground *didn't* open up and swallow me,
so I had to try and laugh it off and ignore the curious faces peeping around
the door from the other room... 

Yes, very embarrassing... but still, I'd love to have heard the waiter trying
to explain to his boss how a glass really had got broken by a falling
meteorite... !  :-))

Stuart A,
(from a very foggy UK)

----------
Archives located at:
http://www.meteoritecentral.com/list_best.html

For help, FAQ's and sub. info. visit:
http://www.meteoritecentral.com/mailing_list.html
----------
Follow-Ups: