Home Plate (Mars)

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Home Plate

HiRISE image of Home Plate.
Coordinates 14.6° S, 175.5°E
Type of feature Rock outcrop
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Home Plate is an informal nickname used by NASA scientists to refer to a geological feature on Mars currently under study by the Spirit 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 a baseball home plate.

Home Plate is a rocky outcrop about 100 meters across with a flat-topped shape; from above, it looks vaguely pentagonal. It is located within the huge Gusev crater, just south of Husband 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. [1]

Spirit is due to spend her third Martian winter on Home Plate's north edge. [2]

Home Plate (upper center), as seen from the summit of Husband Hill.
Home Plate (upper center), as seen from the summit of Husband Hill.

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[edit] Origins

Bomb sag at Home Plate.
Bomb sag at Home Plate.

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 of chloride ions in the surrounding rocks. The presence of bomb sags seems to confirm this hypothesis.[3]

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 mineral hydrates. [4][5]

[edit] References

  1. ^ A.J.S. Rayl. Spirit Homes in on Mitcheltree Ridge, Opportunity Crosses Valley Without Peril. Retrieved on 2007-03-31.
  2. ^ Maggie McKee. Mars rover Spirit to head north for the winter. Retrieved on 2007-12-26.
  3. ^ Squyres, et al. "Pyroclastic Activity at Home Plate in Gusev Crater, Mars". Science 316: 738–742. doi:10.1126/science.1139045. 
  4. ^ Mars Rover Spirit Unearths Surprise Evidence of Wetter Past. Retrieved on 2007-05-30.
  5. ^ Squyres, et al. "Detection of Silica-Rich Deposits on Mars". Science 320: 1063–1067. doi:10.1126/science.1155429. 


[edit] External links

Curious rock with a jutting portion. (Animated GIF image for stereoscopic perception).
Curious rock with a jutting portion. (Animated GIF image for stereoscopic perception).

[edit] See also