Posted to sci.astro:

From: rgregoryclark@yahoo.com (Robert Clark)
Newsgroups: sci.astro,alt.sci.planetary,sci.geo.geology,sci.astro.amateur
Subject: Mesas in Cydonia, Mars are table mountains.
Message-ID: <832ea96d.0202090816.6cefe741@posting.google.com

In the post below I discussed the likelihood that the mesas seen in Cydonia, Mars are table mountains. A report to be presented at the upcoming 33rd LPSC conference will give further support for this by presenting evidence of hematite in this region of Cydonia showing mesas. This implies there was hydrothermal activity in this region which would be supportive of this being a region of hydrovolcanic activity, due to the abundant ice in the region:

HYDROVOLCANIC LANDFORMS IN ACIDALIA AND CYDONIA: PAN-SPECTRAL ANALYSIS WITH
MGS MOC, MOLA AND TES.
http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1820.pdf

The authors found the hematite in the region shown in this image:

Intersection of 'giant polygon' crack and mesa/butte in Cydonia
http://ida.wr.usgs.gov/html/m04005/m0400576.html

Note this is a smaller, separate detection of hematite than seen in the large scale region in Sinus Meridiani:

The Lure of Hematite
http://science.nasa.gov/headlines/y2001/ast28mar_1.htm

Further support for the idea that the mesas are table mountains comes from the appearance of "pyramidal" shaped landforms in the Cydonia area:

Geometric Observations of Cydonia, Mars
http://www.aadm.com/cydonia/Cydonia.htm

These are quite analogous to nunataks seen in arctic regions:

Nunataks sticking up above icefield, northeastern Ellesmere Island
http://www.forum.ic.ac.uk/canada00/feedback.htm

Bob Clark

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From: Robert Clark (rgclark@my-deja.com)
Subject: Re: Mesas in Cydonia, Mars are table mountains.
Newsgroups: sci.astro, alt.sci.planetary, sci.geo.geology, sci.astro.amateur
Date: 2001-08-06 04:20:34 PST

rgclark@my-deja.com (Robert Clark) wrote in message news:<5f181508.0108031038.511afd63@posting.google.com>...
> The mesas on Mars were speculated by Jim Garvin as beig analogous to
> lava domes:
>
> Unmasking the Face on Mars
> "What the picture actually shows is the Martian equivalent of a butte
> or mesa --landforms common around the American West. "It reminds me
> most of Middle Butte in the Snake River Plain of Idaho," says Garvin.
> "That's a lava dome that takes the form of an isolated mesa about the
> same height as the Face on Mars."
> http://science.nasa.gov/headlines/y2001/ast24may_1.htm
>
> A key feature of the mesas in Cydonia is they have concave sides.
> This is different from the form of Middle Butte in Idaho:
>
> Challis Volcanic Group & Intrusive Rocks
> http://imnh.isu.edu/digitalatlas/ida_histgeo/rrt/part2/s2c2p21.html
>
> Such landforms in the northern plains on Mars have previously been
> suggested to be table mountains:
>
> Title: Table Mountains of Mars
> Authors: Hodges, C. A.; Moore, H. J.
> Journal: LUNAR AND PLANETARY SCIENCE IX, PP. 523-525. Abstract. TKO.
> Publication Date: 00/1978
> LPI Keywords: MARS, MOUNTAINS, SURFACE, FEATURES, DESCRIPTION,
> CHARACTERISTICS
> http://adsabs.harvard.edu/cgi-bin/bib_query?1978LPI.....9..523H [full
> text]
>
> Table mountains are formed from volcanic eruptions under glacial ice
> and typically have concave sides and flat tops as seen in the Cydonia
> mesas.
>
> An image of a table mountain on Earth can be found here:
>
> http://isaac.exploratorium.edu/~pauld/summer_institute/summer_day16magnetism/magnetic_globe.html
>
>
> Bob Clark

I was intrigued by what could be the cause of the concave shape of
two of the sides in the structure known as the "Face" as seen on the
"Unmasking the Face on Mars" page. I was rereading a paper by Carlton
Allen, "Volcano-ice interactions on Mars", Jour. Geophys. Res.,
vol.84, no. B14, Dec. 30, 1979, pp. 8048 - 8059, when I noticed that a
mountain in one of the figures also had concave sides. This was of the
table mountain Gaesafjoll, or Gæsafjöll in Icelandic, as shown in an
aerial photo in Fig. 1. of the Allen paper. After searching on the
Icelandic spelling I found one online picture that might contain this
table mountain:

ÍSLANDSVEFURINN Norðausturland - Fjöll
http://www.islandsvefurinn.is/pages/xne/nem.html

Curiously the English version of this page doesn't list the mountains
in the image:

ICELAND WORLDWIDE Northeast Iceland - Mountains
http://www.iww.is/pages/xne/nem.html

An image of a table mountain making clear the concave sides appears
as Figure V-15.1 on this page:

SOUTHWEST ICELAND
Eiríksjökull
http://daac.gsfc.nasa.gov/DAAC_DOCS/geomorphology/GEO_3/GEO_PLATE_V-15.HTML

Another picture of Eiríksjökull is on this page:

http://www.islandia.is/~oskar-e/nature.htm

Other Icelandic table mountains:

Herðubreið
http://www.hi.is/~kbv/her.html

Geitlandsjökull
http://www.islandsvefurinn.is/pages/xs/si2.html

Mount Bláfjall
http://www.hi.is/HI/Stofn/Myvatn/blafjall.htm

Sellandafjall
http://www.ldeo.columbia.edu/~menke/slides/ICELAND/table-mt.html

An explanation for the shape of the table mountains appears on this
pages:

Atlantic Ocean Volcanism
"The effects of confinement on a subglacial lava eruption. Marginal
chilling against melt water results in these unusually steep-sided
cones. One might expect the outer walls to be formed of pillow basalt.
Note the cinder cone on the summit."
http://www.geokem.com/volcanic-atlantic.html

On this page are table mountains using another name for table
mountains, tuyas:

BOX 2 - VOLCANO/ICE INTERACTION WORKSHOP
http://wwwflag.wr.usgs.gov/USGSFlag/Land/IcelandMeeting/Overflight/box2.html

This page also ascribes the shape of the Kirkufell tuya as due to
ice-constrained lava.

Table mountains are shown diagramatically here:

How Do You Get An Ice Sheet Record from a Volcano?
http://www.albion.edu/geology/twilch/Antarctica/Takahe/volcanic-record.htm

Finally, a report given at the 32nd LPSC also concluded that a mesa
in Cydonia, nearby the "Face" structure, was a tuya, i.e., a table
mountain:

Possible Hydrovolcanic Landforms Observed in MOC NA Imagery: A
Preliminary Survey
http://adsabs.harvard.edu/cgi-bin/bib_query?2001LPI....32.1664F

Fig.2 here is of a mesa in the MGS image:

MESA AND BUTTE IN CYDONIA MENSAE
http://ida.wr.usgs.gov/html/sp1220/sp122003.html

Due to their similar form, the nearby "Face" structure is also most
likely a table mountain. Note also that near each mesa there is a
maar, or volcanic crater, as in the image:

Geitlandsjökull
http://www.islandsvefurinn.is/pages/xs/si2.html

Bob Clark

http://groups.google.com/groups?selm=5f181508.0108060320.1921bbeb@posting.google.com

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