Thank you Elton. I'll study on it.
Jerry
--------------------------------------------------
From: "MEM" <[email protected]>
Sent: Saturday, October 09, 2010 1:28 PM
To: "Jerry Flaherty" <[email protected]>; "Meteorite Mailing List"
<[email protected]>
Subject: Re: [meteorite-list] Mars Odyssey THEMIS Images: October 4-8, 2010
The term" rift valley/rift" is somewhat subjective as a rift proper is
normally
associated with plate movement but this example in not from the "tectonic
plate
movement" we are familiar with on earth. This valley resulted from a
"tectonic
process". Specifically a branch of tectonic study called
thrust/contraction
tectonics <http://en.wikipedia.org/wiki/Thrust_tectonics>
The feature is a graben . A graben <http://en.wikipedia.org/wiki/Graben>
is type
of fault feature where contraction( vs compression) pulls perpendicular to
to
the linear features and a block of landscape drops in relation to the
surrounding. On each side of the graben will be steep sloped escarpments.
A
horst is the highland between two grabens that remained at the same
elevation of
may have been up-thrusted.
In the example you posted the movement was a few inches/feet left and
right of
the escarpments( parallel lines) as well as a downward movement of the
valley
floor a distance I am unable to determine from the photo but could have
been
tens to hundreds of feet. This is not a slip strike fault where the
opposite
sides are displaced laterally.
I've read recently about contraction of the lunar crust owing to overall
cooling producing these features. On a lunar-wide basis when the formerly
liquid mantle transitioned to a solid the sum total of all the nanometer
sized
compression of the space between molecules is seen on the surface as these
grabens. The link above shows a substantial graben on the moon.
To read about recent graben formation on earth you might google the
1811-1812
New Madrid Earthquare
or<http://en.wikipedia.org/wiki/New_Madrid_Seismic_Zone>
and the formation of the ReelFoot lake in western Tennessee. That area
lies on a
failed rift where North America almost split. I think the Reelfoot Lake
basin
came from a graben drop of only about 6 ft but left a lake of 30 square
miles
and about 3 ft /1meter deep.
Elton
----- Original Message ----
From: Jerry Flaherty <[email protected]>
To: Ron Baalke <[email protected]>; Meteorite Mailing List
<[email protected]>
Sent: Fri, October 8, 2010 8:22:25 PM
Subject: Re: [meteorite-list] Mars Odyssey THEMIS Images: October 4-8,
2010
A little geologic help please.
In the image "Alba Mons Tectonics" could someone elucidate and elaborate
on
the tectonic features shown.
Are we looking at a rift at one or both parallel "lines" depicted and if
so:
are the lines related
what is the direction of the movement
what specific features demonstrate this movement
any other features which demonstrate tectonic activity that I'm not
seeing
Thanks to any respondents in advance
Jerry Flaherty
--------------------------------------------------
From: "Ron Baalke" <[email protected]>
Sent: Friday, October 08, 2010 5:55 PM
To: "Meteorite Mailing List" <[email protected]>
Subject: [meteorite-list] Mars Odyssey THEMIS Images: October 4-8, 2010
>
> MARS ODYSSEY THEMIS IMAGES
> October 4-8, 2010
>
> o Wind Erosion (04 October 2010)
> http://themis.asu.edu/zoom-20101004a
>
> o Pavonis Mons (05 October 2010)
> http://themis.asu.edu/zoom-20101005a
>
> o Wind Texture (06 October 2010)
> http://themis.asu.edu/zoom-20101006a
>
> o Central Peak Crater (07 October 2010)
> http://themis.asu.edu/zoom-20101007a
>
> o Alba Mons Tectonics (08 October 2010)
> http://themis.asu.edu/zoom-20101008a
>
>
> All of the THEMIS images are archived here:
>
> http://themis.asu.edu/latest.html
>
> NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission
> for NASA's Office of Space Science, Washington, D.C. The Thermal
> Emission
> Imaging System (THEMIS) was developed by Arizona State University,
> Tempe, in co.oration with Raytheon Santa Barbara Remote Sensing.
> The THEMIS investigation is led by Dr. Philip Christensen at Arizona
> State
> University. Lockheed Martin Astronautics, Denver, is the prime
> contractor
> for the Odyssey project, and developed and built the orbiter. Mission
> operations are conducted jointly from Lockheed Martin and from JPL, a
> division of the California Institute of Technology in Pasadena.
>
>
>
> ______________________________________________
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> http://www.meteoritecentral.com/mailing-list-archives.html
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