[meteorite-list] Fried egg crater!

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Sat, 19 Dec 2009 15:30:43 -0600
Message-ID: <C3062A1A579E4B8FB83365004A5D3CFB_at_ATARIENGINE2>

Chuck, Graham, List,

My first thought on seeing the crater candidate
was how much its broad flat "uplift" actually looked
like the so-called "pancake domes" of Venus, believed
to formed by an outflow of "slushy" viscous silica-rich
lava.

I wondered if there were "pancake domes" on Earth.
(Venus I know; the Earth's a mystery.) Particularly,
I wondered if there were pancake domes under the
sea. If this was a pancake dome, the very shallow rim
would merely be the edge of a subsided plain around
the eruption site, and so on.

It turns out there ARE pancake domes under the
Earth's sea (and on land). They're called "cow-patty"
sea-mounts (a more "Earthy" metaphor). They are
usually about 3 km in diameter (the size of this
dome feature).

http://www.thefreelibrary.com/Venus'+pancakes:+a+seafloor+analog%3F-a014998062
    "Supporting these ideas, researchers pointed out
that the pancake domes on Venus bear at least a superficial
resemblance to silica-rich volcanic landforms on Earth.
These include the flattened domes near Mono Lake,
California.
    But a detailed comparison now shows that the volcanic
domes on Earth typically measure one-tenth the width of
those on Venus and have a much rougher terrain, reports
Magellan researcher Jeffrey J. Plaut of NASA's Jet Propulsion
Laboratory. Instead, the pancake features may have more
in common with volcanoes on our planet's seafloor.
    Independent analyses by Nathan T. Bridges, who
conducted his work at the U.S. Geological Survey in
Menlo Park, Calif., and Susan E.H. Sakimoto of Johns
Hopkins University in Baltimore suggest that several flat,
steep-sided seamounts share similarities with the domes
on Venus. These seafloor volcanoes -- sometimes dubbed
'cow patties' because of their flattened appearance -- have
a size, shape, and smoothness akin to the pancake domes,
according to recent sonar data.
    The Earth's seafloor and the surface of Venus have a
key feature in common: Both are under high pressure.
Although the pressure on the ocean bottom exceeds that
exerted by Venus' thick atmosphere, the seafloor may in
fact mimic parts of the Venusian environment better than
any other site in the solar system, Bridges speculates.
Sakimoto suggests that heat transport and the eruption
of magma on the seafloor are similar to such activity on
parts of Venus.
    Because the seamounts are made by basalt, partly
solidified basalt might have the viscosity to create the
flat-top domes, Sakimoto notes..."


Sterling K. Webb
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----- Original Message -----
From: <ensoramanda at ntlworld.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Friday, December 18, 2009 3:48 AM
Subject: [meteorite-list] Fried egg crater!


> Hi All,
>
> Another possible crater/craters...not good hunting territory though!
>
> http://news.bbc.co.uk/2/hi/science/nature/8400264.stm
>
> Graham UK
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Received on Sat 19 Dec 2009 04:30:43 PM PST