Explanation:
Why do portions of this huge crater on Mercury have so much iron?
The unusual
Rembrandt impact basin was discovered recently
in images taken during the robotic
MESSENGER spacecraft's
2008 October flyby of the
Solar System's
innermost planet.
The unusual Rembrandt
spans over 700 kilometers and at 4 billion years old is
possibly the youngest
large impact basin on the planet.
Multicolored images of the crater floor, however, indicate reflections from areas containing unusually high amounts of
iron and
titanium.
These elements
indicate that some exposed materials have not been covered by more recent
lava floes,
and so might originate from an epoch of Mercury's formation.
Data from Rembrandt and across
Mercury
are now being interpreted as indicating a relatively active and volcanic past for Mercury that includes surface tectonics.
Close inspection of the
above image will reveal rings of
Mercury's Rembrandt
impact basin circling around the image center.
Mercury's limb is visible on the upper left, high cliffs and small craters are
visible inside Rembrandt,
and the terminator between night and day runs diagonally through the image.
MESSENGER is on track to fly past
Mercury again this September and enter orbit around
Mercury in 2011.
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