This
fractured surface belongs to a portion of a region called Gorgonum Chaos
located in the southern hemisphere of Mars. Upon closer examination one
finds that these gullies and alluvial deposits, initially discovered by
Mars Global Surveyor, are visible on the trough walls. These gullies appear
to emanate from a specific layer in the walls. The gullies have been proposed
to have formed by the subsurface release of water. |
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Gullies are trenches cut into the land as accelerated streams of water (or
another liquid) erode the surface. To see these focus on the trenches at
the bottom of the image. Running down the walls of the trough are the thin,
dark lines of the gullies. Beneath the grooved, gully channels are faint,
softer-looking fans of material. These are called alluvial deposits. Alluvial
simply means all of the sand, gravel, and dirt that is carried and deposited
by a liquid. On Earth, that liquid is typically water. As the liquid carves
the gully, the eroded material from the channels get carried along and deposited
below in fan-like shapes. |
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