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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 |
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North polar geysers on Mars?
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 |
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Mars geysers "caught in the act?"
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 |
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