- Home Plate (Mars)
MarsGeo
name=Home Plate
caption=HiRISE image of Home Plate.
type=Rock outcrop
latitude=14.6
N_or_S=S
longitude=175.5
E_or_W=EHome Plate is an informal nickname used by
NASA scientists to refer to a geological feature onMars currently under study by theSpirit rover , as of April 2006. It is a rocky outcrop that appears to show layered features. Its name comes from the similarity of its shape with abaseball home plate .Home Plate is a rocky outcrop about 100 meters across with a flat-topped shape; from above, it looks vaguely
pentagon al. It is located within the hugeGusev crater , just south ofHusband Hill .The feature is interesting to scientists because of its layered appearance. "Spirit's" twin, "Opportunity", currently studying sites on the opposite side of the planet, has discovered numerous layered rocks, but Home Plate is the first example to be found at Spirit's site. It bears a striking similarity to
Burns Cliff , a feature studied by Opportunity at Endurance crater.Spirit arrived at Home Plate on sol 744 (
February 7 ,2006 ) and has completed a scientific investigation with her robotic arm before moving to Low Ridge Haven due to power concerns. She returned on sol 1126 to resume those studies. [cite web|url=http://planetary.org/news/2007/0331_Mars_Exploration_Rovers_Update_Spirit.html|title=Spirit Homes in on Mitcheltree Ridge, Opportunity Crosses Valley Without Peril|author=A.J.S. Rayl|accessdate=2007-03-31]Spirit is due to spend her third Martian winter on Home Plate's north edge. [cite web|url=http://space.newscientist.com/article/dn12884-mars-rover-spirit-to-head-north-for-the-winter.html|title=Mars rover Spirit to head north for the winter|author=Maggie McKee|accessdate=2007-12-26] __TOC__
Origins
Scientists now believe that Home Plate is an explosive volcanic deposit. It is surrounded by deposits of
basalt , which exploded on contact with water. The presence of brine is further supported by the high concentration ofchloride ion s in the surrounding rocks. The presence ofbomb sag s (laminae typically found in beds of volcanish ash) seems to confirm this hypothesis. [cite journal|journal=Science|author=Squyres, et al|title=Pyroclastic Activity at Home Plate in Gusev Crater, Mars|pages=738–742|volume=316|doi=10.1126/science.1139045]A patch of 90% pure opaline
silicon dioxide was unearthed by Spirit in the vicinity of Home Plate. The patch is believed to be formed in acidic hydrothermal conditions, which supports the theory that Home Plate is of a explosive volcanic origin. Water is also present as mineralhydrate s. [cite web|url=http://www.nasa.gov/mission_pages/mer/mer-20070521.html|title=Mars Rover Spirit Unearths Surprise Evidence of Wetter Past|accessdate=2007-05-30] [cite journal|journal=Science|volume=320|pages=1063–1067|author=Squyres, et al|title=Detection of Silica-Rich Deposits on Mars|doi=10.1126/science.1155429]References
External links
* [http://mars.jpl.nasa.gov/ Nasa's Mars Exploration Program]
* [http://marsrovers.nasa.gov/mission/traverse_maps.html Current position of the Mars rovers] - Home Plate is visible, with Spirit's journey around it.
* [http://www.marsgeo.com/Spirit/HomePlate.htm www.marsgeo.com The Geology of Home Plate]
* [http://www.planetary.org/blog/article/00000452/ The Planetary Society Weblog: Home, Sweet Home for Spirit]
* [http://marsrovers.jpl.nasa.gov/ Official Mars Rovers site]ee also
*
List of rocks on Mars
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