Researchers have determined the now-infamous Martian rock resembling a jelly doughnut, dubbed Pinnacle Island, is a piece of a larger rock broken and moved by the wheel of NASA's Mars Exploration Rover Opportunity in early January.
Only 40 mm wide, the white-rimmed, red-centered rock caused a stir last month when it appeared in an image the rover took Jan. 8 at a location where it was not present four days earlier.
More recent images show the original piece of rock struck by the rover's wheel, slightly uphill from where Pinnacle Island came to rest.
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Examination of Pinnacle Island revealed high levels of elements such as manganese and sulfur, suggesting these water-soluble ingredients were concentrated in the rock by the action of water.
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JPL manages the Mars Exploration Rover Project for NASA's Science Mission Directorate in Washington. For more information about Spirit and Opportunity, visit: http://www.nasa.gov/rovers .
Reading these sites you posted and the minerals found reminded me of my college geology classes,
The order of solidification from magma:
My goodness, that was 58 years ago.
I appreciated learning mnemonics when a school boy. Two examples:
When very young there was Richard of York Gave Battle in Vain.
When older and building radio sets there was "Buy better resistors or your grid bias may go west".