Home Plate Mars rover summary

[aldo12xu]

Hi folks,<br /><br />For those of you following the Spirit Mars rover, you know it's returning some cool images and info about the geology of Home Plate. There's been discussions on this and other forums about the latest observations and theories on Home Plate's origin. Well, I summarized those observations and posted them on my website to help sort things out. <br /><br />So hopefully people will find it useful while we're waiting for NASA to give us a more comprehensive report on Home Plate. The link to the summary is on my homepage.<br /><br />Cheers, Aldo.<br /><br />

 

[ag30476]

Hey nice site. Thanks.

 

[aldo12xu]

Thanks ag, <br /><br />Any thoughts from the geology orientated members out there on the latest microscropic images of outcrops from the top of Home Plate?<br /><br />To me the texture looks volcanic. What about those small dark spheroids? They don't look like clastic grains. Are they vesicles, amygdules, or beads of basaltic glass? <br /><br />http://marsrovers.jpl.nasa.gov/gallery/all/2/m/763/2M194100779EFFAODQP2956M2M1.JPG <br />

 

[aldo12xu]

Apparently the latest working model is that Home Plate may represent the eroded remnants of a volcanic tuff cone or maar volcano. The idea is that as the magma moved through the Columbia Hills rocks there was enough moisture in the rocks to interact with the magma, resulting in an explosive form a volcanism. <br /><br />From the Planetary Society:<br />http://www.planetary.org/news/2006/0228_Mars_Exploration_Rovers_Update_Spirit.html <br /><br />So those dark beads in the microscopic image above might actually be former droplets of basaltic glass that were explelled in the expolsion.<br /><br />--Aldo--

 

[exoscientist]

Maars and tuff cones arise from volcano/water interaction. Some examples here: <br /><br /><br />Volcanic Features of Victoria's Western District. <br />http://members.iinet.net.au/~boxer/WesternDistrict.htm <br /><br />What might be key are the "bomb sag" features given on the "Volcanic features in Western District of Victoria" page: <br /><br /><br />Volcanic bomb sag in tuffs at the Lake Purdiguluc maar. <br />http://members.iinet.net.au/~boxer/images/24-09-BombSag1.jpg <br /><br /><br />Volcanic bomb sags in tuffs at the Tower Hill maar complex. <br />http://members.iinet.net.au/~boxer/images/24-32-TowerHill_Bomb_Sag1.jpg <br /><br /><br /> Another example of a bomb sag is given on this page: <br /><br /><br />HYDROVOLCANIC ERUPTIONS <br />http://www.geology.sdsu.edu/how_volcanoes_work/Hydrovolcanic.html <br /><br /><br />Here: <br /><br /><br />Bomb sag. <br />http://www.geology.sdsu.edu/how_volcanoes_work/Images/Hydrovolcanic/block_sag2_l.jpg<br /><br /> There was a discussion here about some Spirit images that might show a bomb sag, referred to as a "drop stone": <br /><br /><br />Uncalibrated color image at Home Plate. <br />http://uplink.space.com/attachments//453602-2P193032947EL5M1.jpg <br /><br /><br />Taken from these Pancam images: <br /><br /><br />Panoramic Camera :: Sol 751. <br />http://marsrovers.jpl.nasa.gov/gallery/all/spirit_p751.html <</safety_wrapper> <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Steve Squyres referred to this possible "bomb sag" in his talk in this week's Lunar and Planetary Science Conference:<br /><br />By Emily Lakdawalla<br />LPSC: Wednesday and Thursday: A few Mars Exploration Rover-related talks<br />Mar. 16, 2006 | 15:10 PST | 23:10 UTC<br />"Laterally, you get to one of the most interesting things we have seen, a probable bomb sag in this deposit. A rock has fallen from the sky and has deformed these layers. This is the only one of these we have found anywhere and we have looked hard."<br />http://www.planetary.org/blog/article/00000497/<br /><br /> He offered no conclusion though on whether it supported the maar/tuff cone hypothesis for Home Plate.<br /><br /><br /><br /> Bob Clark<br /><br /><br /> <div class="Discussion_UserSignature"> </div>