Hi Bill
Bill Payne wrote:
> Jonathan,
>
> Thank you for the informative post.
>
Glad you found it useful.
>
> > Possibly snowdrifts accumulating round the aircraft were a factor.
>
> This might be a factor initially, but I would think after the planes were
> buried a few meters the drifts collecting because of the interference of
> the planes would disappear.
>
I agree. A B17 is 3.59 m high. I think at best it is a very partial
explanation.
>
> If 2 m of snow accumulate per year, and the planes were down from 1942 to
> 1992, then 2 m * 50 years = 100 m of dry snow with a density of 0.01. In
> a year and at a depth of 2 m the dry snow becomes firn with a density of
> 0.4, which becomes glacial ice with density of 0.8 at 60 m and 0.91 at
> 100 m. Let's say the average density of the snow/ice from 0 to 80 m is
> 0.6. Then the snow with a density of 0.01 compacts 60 times to become
> ice with an average density of 0.6 (0.01/0.6 = 60). So in 50 years we
> should get 100 m of snow which compacts 60 times to 1.7 m in 50 years. I
> think you said there should be 5 m of cover instead of 1.7 m. What did I
> do wrong? Or were you just ballparking the number?
I am impressed. Your method is much more elegant and accurate than mine.
The only thing you need to allow for is that the uppermost 2 m is going to to
have a density of between 0.01 and 0.6. So 3 m might be the best ball park
figure.
>
> If the rate of burial *were* to be found to be accurate ("higher than
> [recent] average accumulation"?) at 82 m per 50 years, then ice builds at
> about 1.5 m per year, and the 3000 m ice sheet took only 2000 years to
> form. No wonder the YECs like this one.
>
> Bill
The YEC argument is still specious. First, as I pointed out before, the
predicted accumulation rate from counting the lice layers is very close to
extrapolating from present rates. Secondly, if 82 m of ice has accumulated
in 50 years, and assuming an average density of 0.6, then that annual
snowfall would have to be 98.4 m. Even assuming very wet snow (density 0.1)
still requires an extraordinary snowfall over the last 50 years. There is no
evidence for these rates either in the Greenland meteorological records
(Remember that the ice cap is a cold desert) or in the long term rates
deduced from the annual layers in the ice cores.
One minor quibble. In your calculation, you need to allow for the fact that
the ice has to increase in density to 0.9 m, the timenecessary, assuming the
98 m annual snowfall you require, to build up 3000 m of ice is 2700 years not
2000.
Respectfully
Jon
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