This image mosaic from the microscopic imager aboard NASA's Mars
Exploration Rover Opportunity shows detailed structure of a small fin-like
structure dubbed "Roosevelt," which sticks out from the outcrop pavement
at the edge of "Erebus Crater."
Roosevelt lines a fracture in the local pavement and scientists
hypothesize that it is a fracture fill, formed by water that percolated
through the fracture. This would mean the feature is younger than
surrounding rocks and, therefore, might provide evidence of water that
was present some time after the formation of Meridiani Planum sedimentary
The image shows fine laminations (layers about 1 millimeter or .04 inch
thick) that run parallel to the axis of the fin. Some of the textures
visible in the image likely indicate that minerals precipitated from the
outcrop rocks, but sediment grains are also apparent.
The three frames combined into this mosaic were taken during Opportunity's
727th Martian day, or sol (Feb. 8, 2006). In subsequent days, the rover
completed textural and chemical inspection of Roosevelt to help the
science team understand this structure's significance for Martian history.
Image Credit: NASA/JPL/Cornell/USGS
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