Large animal extinctions - part 2
Timo Niroma (timo.niroma@tilmari.pp.fi)
3 Jul 1996 22:18:58 GMT
In article <4rabil$ma5@maze.dpo.uab.edu>, karen@uab.edu (Karen ) says:
>
>p3voices <p3voices@earthlink.net> wrote:
>
>(snipped for reasons explained in part 1)
>
Continued ... part 2.
I have corrected all those 12600 years in Karen's letter to 11600
years, because it was my error, as I explain in the first part.
5. "Is there any evidence to support the contention that there were so
few men and so many big animals 11600 years ago in the Americas?"
I have gathered all scientific estimates I have found about the amount
of people in North America 11000-12000 years ago and they range from
800 to 12500. Estimates of the amount of animals are more scarce, but
all estimates of the amount of mammoths, mastodonts and elephants I've
seen have five numbers.
6/A. Me: "My pet theory says that it was an allright catastrophe caused
by an asteroid or a comet hitting the Northern Atlantic."
6/B. Karen: "What happened 11600 years ago that hints at that
direction?"
a. Ice Age ended after having lasted for about 100,000 years, not
slowly, but in less than 3 years (probably during one year).
b. The temperature both in Greenland and Vostok (Antarctica) rose
suddenly and permanently from one varve to the next (1-2 years) by 14
degrees Celsius.
c. CO2 in atmosphere rose from 180 ppm to 240 ppm.
d. delta18-O rose fourfold.
e. The climate in tropic suddenly warmed and changed drier in some
decades. The warming in Africa was about 5 degrees, in the oceans 2-3
degrees, except in North Atlantic 5 degrees.
f. The radiocarbon dating of the megafauna show that it went into
extinction in North America and Siberia 10500+-500 BP, which calibrated
to calendar years is 11500+-500 years. For example Mammuthus columbi
in Clovis sites (Nebraska, Missouri, Texas, Arizona, Oklahoma, New
Mexico, Colorado, Wyoming) plus non-Clovis sites (South Dakota,
Wyoming, Texas), Mammut americanum (Michigan, Ohio).
g. Paleo-Indian legends, Edda, without date, except Plato: 9000 years
before Solon's visit to Sais, Egypt.
h. Taurid complex, the progenitor of comet Encke, near Earth.
7. "If there had been a major flood causing massive extinctions in
North America, wouldn't it have caused human extinction as well?"
The flood, whether from tsunami, torrential rains or melting of the ice
sheets were far away the only reasons for the catastrophe. An
extraterrestrial impact would also cause temporary loss of photosynt
hesis, winds (500 km/h plus), hot, forest fires, pyrotoxins, acid rain,
ultraviolent radiation (ozone hole), volcanism all around, earthquakes.
It certainly drived men into the brink of extinction, that's the main
theme in the flood legends.
8. "When you say such a high increase in temperature in such a short
time, exactly what increase in temperature are you talking about and
exactly how short a time are you talking about?"
Dansgaard with his workgroup found already in the late 1980s that
Greenland ice core proved that there was a permanent increase of at
least 7 degrees in less than 3 years 11600 years ago. In the early
1990s the time was lessened to 1 year. In 1995-96 there has been new
investigations both from Greenland and Antarctica that show that the
rise of the temperature was twice that amount or about 14 degrees
Celsius.
9. "How does this make your idea more plausible."
It's the simplest explanation that is offered to such an increase in
the temperature.
10. "You say that the impact theory for the extinction of the dinosaurs
has been eagerly accepted but this is misleading since for at least ten
years, paleontologists scoffed at the Alwarez theory."
I suggested this theory already in 1975, but could defend it only by
Occam's razor, because I had no hard evidence, only the logic. The
situation is analogical today as to the Ice age end, and as it was when
I as a schoolboy already in the 1960s wrote a 30-page treatise that
against all authorities insisted that Lappajarvi is a meteorite crater,
which was proven only in 1974. I felt very relieved when I read about
the Alwarez founding the iridium in 1980. I followed very keenly the
debate that raged the whole 1980s. The astronomers, to which group I
count myself as an active amateur, accepted it almost immediately,
geologists as last ones in their conference in 1989. Now we have the
Chicxulub.
----------------------------
Okay, if you have a better explanation for the catastrophic end of the
ice age, I would like to hear. And I'm ready to change my theory, if
it is proved to be wrong. Until then I regard it as the best
explanation, if not by other reasons, at least by Occam's razor. But
even if it proved wrong, it is not absurd. Or was the bombardment that
Jupiter suffered from a comet in 1994 somehow absurd? Or would it have
been absurd if the Tunguska asteroid would have twice as big and caused
a global catastrophe?
Friendly,
Timo
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