Jonathan,
Thank you for the informative post.
On Tue, 16 Jan 2001 11:39:17 +1100 Jonathan Clarke
<jdac@alphalink.com.au> writes:
> However, this does not mean that all is clear about the glaciology
> of the site. With the described accumulation on site and the
> compaction rate from the Camp Century ice core, the
> aircraft should be buried to a depth of about 5 m. Clearly the
> aircraft are much deeper than they should be. I don't know why this
> is the case. [snip]
> 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.
> As you suggest, most likely some glaciological/meterological process is
the
> answer. it could involve flow, lower compaction ratios, or higher
> than average accumulation. What it might be I have no idea.
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?
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
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