Team Meeting & Science Themes
We’re in the midst of another HiRISE team meeting here in Tucson. I can’t believe it’s been almost two years since the team meeting I blogged about here. There are a few new faces, but mostly familiar friends that we’ve worked with for years by now. Our two newest Targeting Specialists are meeting the science team for the first time. (They’re actually not that “new” any more – they started last June, but this is their first team meeting.) Some of the other new folks are students and post-docs who are working on interesting research projects using HiRISE data. There are also a few people from JPL here at the meeting, who we talk to on the phone and email often, but we’ve never actually met face-to-face before.
Today during the meeting we are getting updates on all the Science Themes. Our images are divided into groups according to the geologic process that we hypothesize occurred. For each of these themes, a Science Theme Lead is assigned. These “STLs” are Co-Investigators or postdocs who are experts in that area. For example, the Volcanic Processes theme contains images intended to explore phenomena related to volcanism, such as inflated lavas, water-lava interactions, volcanic pits and cones, and mysterious types of collapse features such as the one shown in the anaglyph to the left. As you can read in the caption for that image, we’re still not sure how this feature formed. There are several different possibilities. The image was originally placed in the Impact Processes theme because that was one hypothesis. However, after seeing the high resolution image and stereo data from HiRISE, formation by a meteor impact doesn’t seem as plausible. Collapse after loss of material beneath the surface, such as magma or water, is a better fit to our observations.
February 2nd, 2009 at 11:47 am
[...] Mars HiRISE Camera Update: Team Meeting & Science Themes [...]
February 3rd, 2009 at 11:30 am
Actually, the main feature in PSP_5813_2150 may have been ‘instigated’ by an impact followed by subsequent collapse. Given that there is ejecta and several rays, as well as numerous crater chains radial to the feature center, I can’t imagine any other mechanism that could generate those features alone. The only volcanic mechanism I can think of is a maar (e.g. http://en.wikipedia.org/wiki/File:Ukinrek_Maars,_Alaska.jpg), but I don’t see how a maar can create those crater chains. Interestingly, surrounding the main feature are ‘fields’ of smaller circular features that at first look like pedestal craters, but I suspect are some type of rootless cones, indicative of magma/water interactions; one field of these smaller features also appears to have been partially destroyed by the larger collapse.
As a model, I hypothesize that the ground was very water saturated (given the soft sediment deformation seen in the interior ‘rim’), then an impact occured which through ejecta out and formed the crater chains, but additionally vaporized a fair amount of subsurface water causing the subsequent collapse terracing we see. If the impact was near vertical and if the target was very saturated, most of the target would launch more vertically than horizontally (i.e. >45deg. as seen in early experiments by Greeley), perhaps explaining the limited horizontal extent of the ejecta.
February 5th, 2009 at 6:15 am
To me rootless cones seems more likely.
If it is a maar type feature than the only possibility of the maar not being a regular ’shape’ is if it formed inside a nested caldera, like that atop Olympus Mons. However there’s no evidence of this particular feature being that & no maar features do not form crater chains.
Talking of science objectives, will HiRISE ever be used to observe Deimos, as has already been done to spectacular effect with Phobos?
Also glacial type features in Tharsis?
http://www.google.com/url?sa=U&start=4&q=http://www.lpi.usra.edu/meetings/modeling2008/pdf/9030.pdf&ei=tOWKSZvyOOTSjAfKj5WWCA&usg=AFQjCNFAqkiAM642zJ76-PGwOyNK93WOYw
The volcanoes are fascinating anyway & the search for cinder cones, signatures of inactive fumeroles (may be difficult due to the dust), greater HiRISE coverage of the caldera floors, etc, to pin down more precisely the last active periods.
The MGS MOC appeared to be very effective with this & HiRISE could follow on with those investigations.
Whether or not it would be worth to follow on with continued searches for Mars Polar Lander & Beagle 2 is doubtful, though it would be great to get further evidence of what may have gone wrong in either case, though I have heard suggestions that Beagle 2 may have missed Mars completely & ended up in heliocentric orbit, though I do not think that is the case.
Andrew Brown.