[meteorite-list] Feedback: try this specific crater "R5" in Argentina: Darren Garrison: Rich Murray 2009.10.15

From: Rich Murray <rmforall_at_meteoritecentral.com>
Date: Thu, 15 Oct 2009 23:46:59 -0600
Message-ID: <ECEEF4974F314DC4AA1344D55032B5B2_at_ownerPC>

Re: [meteorite-list] Feedback: try this specific crater "R5" in Argentina:
Darren Garrison: Rich Murray 2009.10.15

Hello Darren Garrison,

Very apt! You have very high aptitude...

Here's a nice view to try Google Earth on:

R5 -41.474665 -67.912145 3.0 round,
flat shallow 1.3 white core, .968, 1.167 area el 1 km N
also crater 1.2X.6 on SW rim,
5 km E of Rd 8 ns, 28 km N of Rds 5 and 7.
1X.5 green [farm?] on NW rim of white core, with road.
Part of a regional crater field on a dark, incised plateau -- the
edges of the plateau are dark layers .1 km deep at least.
This area is 130 km N of the Bajada del Diablo impact crater field.

Sometimes clouds and their shadows look like craters,
and some features are sinkholes, circle irrigation farm fields,
farming terraces on hillside slopes, multitudes of oval
freeze-thaw lakes in permafrost regions, orphan oxbow loops
in river valleys, volcanos, and calderas,
or mud, ice, or human dams on rivers, as well as mines,
springs, inclined surface faults, valleys in mountain fold belts.
I was fooled this year by piles of yellow sawdust in an
abandoned sawmill yard in Las Vegas, New Mexico,
until I visited the site. Cowpaths that radiate from a central
stock tank make intriguing patterns, seen from above.

However, impacts can initiate, modify, or overlap any of
these -- for instance, an impact could create a shallow
long crater of cracked rocks on the west side of Santa Fe
Baldy, that might supply ground water and sustain an unusually
high altitude pine forrest, readily seen from Santa Fe.
On the east side I see [ 35.84 -105.75 ] a .13X.08 pond
at 3.494 km altitude on Google Earth. Google Maps- Terrain
often colors many ponds and lakes blue, expediting searches.

Briefly, Carolina Bays (bays mean a particular type of tree in
North and South Carolina) are in the range 0.1 to 20 km,
probably ice or slushy comet fragment impacts at low
velocity ( 5 km/sec ), commonly carrying white sand and
minerals, at small angles under 10 degrees, like raindrops
on a moving car's windshield, leaving shallow, flat craters,
blasted but not melted or vaporized, with low rims, higher
on the exit direction of movement, with little or no metal
or stone from the objects. The shapes include round, oval,
and irregular. They are especially visible on flat, dry bedrock
areas above 1 km altitude, slower to be eroded, filled,
or overgrown.

There is a typical region from Las Vegas, New Mexico,
north, east, and south for 10 to 30 miles, with scores
of impacts, usually with associated white deposits,
which, of course, would be moved a lot by wind and water.
The uniform character of these unburied craters hints at
a recent Holocene origin. I've found many samples of
bedrock sandstone and lava rocks that seem to have
been coated with a firm 0.1 to 10 cm layer of white minerals --
I envison it coming from a high-pressure blast of very hot mineral
laden steam.

Drawing upon ideas from many sources, many of which will
be soon domumented in other posts, I agree that many ice
comets exist, with great variation in origin (early solar system
accretion, impacts and collisions on moons and planets with
surface water or ice), variable composition (mostly water,
any amount of various minerals, some inclusion of ordinary
metals, stones, organics, common gases), size, temperature
(cyrogenic solid, hot or warm from recent impacts or
solar perigees, surface only wamth), density ( solid to boulder
piles to spongey fractal types to dust balls), fragmentation
(none, a few huge pieces in a cluster or line of flight, fractal
cloud of pieces, velocity, angle of approach, orbital
reoccurence), spin (direction and amount), and target areas
(mountains, bare plateaus, lowland deserts, jungles, and coasts,
human development, water and ice areas and depths).

Impact scenarios for 5 km/sec low velocity impacts at low
angles (5-10 degrees), with significant air resistance at 125 km
for a mostly ice, cyrogenic, dense comet with 1,000 kg/m**3
density might be:

1. surface melting creates streamlining, enough to prevent
breakup and explosive airbursts, and creating enough lift
to lower the angle of descent and reduce the velocity
(or later enough drag to cause a lower velocity falling impact
at high angles).

2. As the lower surface encounters denser air, spinning
may be caused, which may around the axis of velocity as a
evolving cigar shape, or like a wheel, forming a sideways
spinning sausage vortex, bent back on both sides like
a "V".

3. Thus, the start of contact might leave 1, 2, 3, or more
parallel grooves, growing in width and depth.

4. The dense core of the object may often leave a
characteristic entry corridor, a valley with increasing
depth -- showing the effective diameter of the object.

5.The main impact of the dense core will make the
deepest part of the crater, still with little melting or
vaporizing of the target rock, but it will be highly cracked,
fragmented, and powdered, while the mineral
laden high pressure high temperature steam
at the zone of impact will quickly deposit layers
of minerals on the floor, dislodged fragments,
and flying objects -- when white, these coatings appear
to be ordinary caliche deposits. Of course, water
erosion of white layers will lead to redistribution as
caliche deposits.

6. Expanding as a pancake of dense gases, dusts,
and fragments, the blast will make a shallow crater,
round, oval, or highly irregular,
with a single low rim, higher in the direction of movement,
often with a thin layer of ejecta past the rim.

7. Much of the forward momentum will make 1,2, more,
or a fan, grooves, channels, and lobes, ending in frozen flows
and deposits, sometimes with front and side ridges.

8. Hot dense high velocity sheets of mineral laden steam
may, as they shoot over huge rocks, create enough
aerodynamic lift to raise them and carry them, depositing
them downwind as erratics -- the same principle that
causes flowing air to generate lift over convex airfoils
(the commonly cited Bernoulli effect creates only a
fraction of the lift, while pressure on the bottom of
a upward inclined flat airfoil creates some more of the lift,
with the cost of increased drag resistance).

Enjoy,
Rich Murray 505-501-2298 rmforall at comcast.net


----- Original Message -----
From: "Darren Garrison" <cynapse at charter.net>
To: <meteorite-list at meteoritecentral.com>
Sent: Thursday, October 15, 2009 11:40 PM
Subject: Re: [meteorite-list] Feedback -- will get both from fine
townlibrary interlibrary loans -- you sold me MIA about 2 monthsago --
Thanks muchly!: Ed Grondine: Rich Murray 2009.10.15


> On Thu, 15 Oct 2009 22:14:36 -0600, you wrote:
>
>>Paul H, since I started posting about April to various lists, no one has
>>agreed with me...
>>
>
> Well, you said that there was a new consensus, after all...
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Received on Fri 16 Oct 2009 01:46:59 AM PDT