Inverted topography

From Wikipedia, the free encyclopedia

Inverted channels on Mars. These curved and crisscrossing ridges in the Aeolis region were once channels in a sediment fan. The channels were more resistant to wind erosion than the surrounding materials, so now they are left standing as ridges rather than valleys. Image Credit: NASA/JPL/Malin Space Science Systems

Inverted topography or topographic inversion refers to landscape features that have reversed their elevation relative to other features. It most often occurs when low areas of a landscape become filled with lava or sediment that hardens into material that is more resistant to erosion than the material that surrounds it. Differential erosion then removes the less resistant surrounding material, leaving behind the younger resistant material which may then appear as a ridge where previously there was a valley. Terms such as "inverted valley" or "inverted channel" are used to describe such features. Plateaus, mesas and buttes may also be formed as inverted features. Examples of inverted topography have been discovered on Mars.