Re: KT Boundary Inquiry

In article <g%L2g.698687$084.569421@attbi_s22>,
" George" <george@xxxxxxxxxxxxxxxxxxxxx> wrote:

"Alan Kellogg" <mythusmage@xxxxxxxxxxxxxx> wrote in message
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In article <KPa2g.695261$084.275927@attbi_s22>,
"George" <george@xxxxxxxxxxxxxxxxxxxxx> wrote:

"Alan Kellogg" <mythusmage@xxxxxxxxxxxxxx> wrote in message
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In article <XS82g.695129$084.428317@attbi_s22>,
"George" <george@xxxxxxxxxxxxxxxxxxxxx> wrote:

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George wrote:
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George wrote:
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Alan Kellogg wrote:
Where can I find up-to-date information on the period of
time
leading
up
to the KT Extinction Event?

Walter Alvarez's book "T. Rex and the Crater of Doom"

I believe the question was about "up-to-date information".
Isn't
that
book
nearly ten years old?

So?

So, it is not up-to-date information. It is also not an unbiased
view
of
the current thinking.

Seems pretty thorough to me. Can you point out significant weak
points
in his book?

The weakest link in the book is that it is ten years old. As such,
there
has since been tons of data collected and interpreted, a lot of which
questions whether an impact actually caused the dinosaurs to go
extinct.
The date of the Yucatan impacter has been brought into question - it
may
be
older than the K-T boundary event. That and the fact that the famous
irridium layer has been found right smack in the middle of the Deccan
traps, a fact which not only helps date the traps, but indicates that
the
volcanism associated with them was ongoing before during and after
the
K-T
boundary event. In other words, a lot of data has been collected
that
dispute the impact theory of the demise of the dinosaurs, and that
supports
the volcanism associated with the Deccan traps and the resulting
climate
change as a possible major cause. These are my major beefs with the
book.
I'm sure there are others I've overlooked.

The fact that the largest extinction level event in geologic history,
that
of the P-T event, is not associated with an impact, but is associated
with
the Siberian traps weakens the impact theory for the K-T event, and
strengthens the theory for the Deccan traps being the most likely
cause
of
the changes which resulted in the demise of the dinosaurs and many
other
lifeforms. Stay tuned.

George

Now, the Siberian Traps occured during major climatological changes
caused by the formation of Pangea, thus I can't hold the Traps
entirely
responsible. Nothing so dramatic was going on when the Deccan Traps
were
underway, except for the Chixilub impact. Thus I consider it most
likely
that the impact was contributory to the extinction event at the K-T
Boundary, much as the formation of Pangea was contributory at the P-T
extinction event. In either event too many severe changes too fast for
certain species to survive.

I can't say that I agree with that assessment. Data from the nearly
complete P-T boundary stratigraphic sections located in Greenland appear
to
indicate severe climate changes that coincided with the production of
the
Siberian Traps. It has been postulated that the Siberian volcanism
caused
a rise in global temperatures that was high enough to cause rapid
release
of clathrates built up on the ocean floor. The sudden release of such
huge
quantities of methane is suggested to have resulted in a runaway
greenhouse
that caused the extinctions. In addition, the evidence suggests that
this
happened repeatedly over an extended period of time, and very nearly
coincided with the periodic eruptions in Siberia. That there were two
'great dyings' that coincide or nearly coincide with the release of
massive
quantities of basaltic lava onto the Earth's surface certainly does make
a
strong case that the events (the extinctions and the production of
prodigious amounts of lava) are linked.

George

What of the climatic changes produced by the assembly of Pangea at or
around the same time? As I said, contributory.

I've not seen an papers that describe climate changes resulting from the
coming together of the continents toform Pangea. Obviously, they would
contribute to climate change in some way, but whether it would beenough to
wipe out 95% of all species, I have a doubt. But then, neither have I seen
the data.

I don't doubt the Siberian Traps would've produced a massive extinction
event in and of themselves, but the contemporaneous tectonic events
surely made matters much worse.

Why? What tectonic changes could have had a more severe effect on land and
aquatic life than the production of so much greenhouse gas, and the
resulting increase in global atmospheric and oceanic temperatures, and how?

George

Habitat loss; coastal becomes inland, oceans currets chang,; wind
patterns change, marshes and swamps dry up, change in humidity both
local and world wide, change in sea leves, mountain building. Enough
changes to place sufficient stress on species to push them over the edge
towards extinction. Thus exaserpating the extinction event.

George, you are a tad too enamored of the Siberian Traps. They were,
after all, not the only act at that concert.
.

Relevant Pages

  • Re: KT Boundary Inquiry
    ... George wrote: ... to the KT Extinction Event? ... traps, a fact which not only helps date the traps, but indicates that the ... dispute the impact theory of the demise of the dinosaurs, ...
    (sci.bio.paleontology)
  • Re: KT Boundary Inquiry
    ... George wrote: ... traps, a fact which not only helps date the traps, but indicates ... The fact that the largest extinction level event in geologic ... the Siberian Traps occured during major climatological ...
    (sci.bio.paleontology)
  • Re: KT Boundary Inquiry
    ... George wrote: ... traps, a fact which not only helps date the traps, but ... The fact that the largest extinction level event in geologic ... the Siberian Traps occured during major climatological ...
    (sci.bio.paleontology)
  • Re: KT Boundary Inquiry
    ... George wrote: ... traps, a fact which not only helps date the traps, but indicates ... The fact that the largest extinction level event in geologic ... the Siberian Traps occured during major climatological ...
    (sci.bio.paleontology)
  • Re: KT Boundary Inquiry
    ... traps, a fact which not only helps date the traps, but indicates that ... The fact that the largest extinction level event in geologic history, ... the Siberian Traps occured during major climatological changes ... I've not seen an papers that describe climate changes resulting from the ...
    (sci.bio.paleontology)