North polar geysers on Mars?

Fan shaped deposits at the south pole have been attributed to CO2 gas
geysers:

Gas jets spawn dark 'spiders' and spots on Mars icecap.
http://themis.asu.edu/news-polarjets

This MOC image might show a similar process occurs at the north pole:

North polar terrain.
http://ida.wr.usgs.gov/html/r15000/r1500035.html

MOC image of Mars north pole.
http://uplink.space.com/attachments/...0035a-comp.JPG


Blown up image of the fan deposits:

http://img238.imageshack.us/img238/3...hpolardhy1.jpg

Dana Johnson on the Mars forum Markcarey.com/mars/ produced this
blown up image:

North polar geysers?
http://www.marsroverblog.com/discuss...r-geysers.html

In post #5 in that thread he noticed there are deposits on both sides
of dunes that are fan shaped. On one side of the dunes, the fan-shaped
deposits are more compact and not as blown out by the wind. The wind
direction determines which side the more blown out deposits are on.
The deposits on either sides of the dunes seem to originate from a
point source at the crests of the dunes.
In his post Johnson, argues the deposits are due to a liquid flow but
I can't confirm this.



Bob Clark

On Jul 27, 11:28 am, Robert Clark wrote:
Fan shaped deposits at the south pole have been attributed to CO2 gas
geysers:

Gas jets spawn dark 'spiders' and spots on Mars icecap.http://themis.asu.edu/news-polarjets

This MOC image might show a similar process occurs at the north pole:

North polar terrain.http://ida.wr.usgs.gov/html/r15000/r1500035.html

MOC image of Mars north pole.http://uplink.space.com/attachments/...0035a-comp.JPG

...

This report to the 7th International Conference on Mars may give
another example of the north polar geysers in Fig. 4:

BASAL SUBLIMATION OF THE SEASONAL CAPS AND SUB-ICE GAS FLOW: A MAJOR
GEOMORPHOLOGICAL AGENT IN THE MARTIAN POLAR REGIONS.
Sylvain Piqueux and Philip R. Christensen, School of Earth and Space
Exploration, Mars Space Flight Facility, Arizona State University,
Tempe AZ 85287, USA, .
Seventh International Conference on Mars 3069.pdf
http://www.lpi.usra.edu/meetings/7th...7/pdf/3069.pdf

In Fig. 5 of this report is also given an example of a formation that
might be a north polar analogue of the "spiders" that had already been
seen at the south pole.
The authors also discuss polygonal terrain seen nearby. They
attribute these polygons to CO2 gas release, as has been used to
explain the geysers and the "spiders".
However, on Earth such polygonal terrain is due to freeze-thaw cycles
in periglacial regions requiring liquid water in the thaw phase.
Then liquid water or brines at the poles on Mars, perhaps protected
by a dust or ice cover, may be involved in the formation of the
geysers and "spiders" as well.

Here's the image containing possible north polar geysers in that
report:

Traverse across north polar scarp.
http://ida.wr.usgs.gov/html/e20001/e2000185.html

A follow up to that image is contained he

North polar defrosting dunes repeat portion of E20-00185.
http://ida.wr.usgs.gov/html/e21002/e2100248.html

The authors of the report also noted the geysers appeared to orginate
from dune crests.
Here is a list of MOC images of north polar dunes:

MOC Images of North Polar Dunes.
http://www.markus-harder.de/dunes.html

This may be a good place to start to search for other examples of the
geysers.


Bob Clark

This report presented to the 7th International Conference on Mars
suggests they *might* have seen one of the more common south polar
geysers actively venting:

HiRISE Views of the Sublimation of Mars' Southern Seasonal CO2 Cap.
C. J. Hansen1 , C. Okubo2, A. McEwen 2, Shane Byrne3, E. DeJong1, K.
Herkenhoff3, M. Mellon4, P. Russell5, and N. Thomas5, 1Jet Propulsion
Lab, Pasadena, CA 91101, 2University of Arizona, Department of
Planetary Sciences, Tucson, AZ 85721, 3USGS, 2255
N. Gemini Dr., Flagstaff, AZ 86001, 4University of Colorado, Boulder,
CO, 5Physikalisches Institut, Universitaet Bern, Schweiz.
Seventh International Conference on Mars 3364.pdf
http://www.lpi.usra.edu/meetings/7th...7/pdf/3364.pdf

From the report:

"Our approach was to attempt to detect dust
plumes by acquiring stereo images separated by a very
short time interval. Near the pole the orbit groundtracks
are closely spaced allowing us to image a given
location with just one orbit (~2 hour) separation. Any
geyser-like activity should be detectable in stereo images
as a plume rising above the surface. The hypothesis
that every spot is a site of gas jets [3,4] implies
that the probability of catching a geyser in action
is very high."
HiRISE Views of the Sublimation of Mars' Southern Seasonal CO2 Cap, p.
1.

and:

"At one location in the Manhattan Island region, using
our stereo imaging technique, we may have captured
a geyser in the process of eruption. It is a tenuous
detection at best, very near the limits of the camera
capability. The putative plume is not high above the
surface ( 10m high) and is optically very thin. In
stereo small bumps on the surface can be observed that
may be the site of other gas jets. Figure 5 shows the
bumps and small fans that may be the initiation of the
gas release. They show up in stereo as small localized
slightly elevated areas on the surface. Figure 6 shows
the fan we believe may be actively venting."
HiRISE Views of the Sublimation of Mars' Southern Seasonal CO2 Cap, p.
3.


Here's a link to the 3-D anaglyph from the report *possibly* showing
a venting geyser:

http://uplink.space.com/attachments/...r-anaglyph.JPG

In Fig. 1 of this report are also given color before and after images
of a geyser region. The authors do not say these images are "false
color" or "enhanced color", but it is interesting the changes appear
blue in color.


Bob Clark