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Impact Melt Features in Tycho Crater's Floor
12.09.10
 
Depressions and positive relief features in Tycho crater › View larger image
Depressions and positive relief features in Tycho crater were caused by a complex mixture of granular material and impact melt settling to the floor. Image width is 370 m, LROC NAC M119923147L [NASA/GSFC/Arizona State University].


Impact melt creates a wide variety of features on the Moon. These include melt ponds, draped ejecta, viscous flows, linear and nonlinear depressions, and positive relief features. As impact melts mix with loose rock during crater formation, solid pieces of rock stick above the surface of the ponding melt to form little peaks (positive relief features). The depressions are possibly cooling fractures in the melt that result as the melt slowly solidifies and contracts (the opposite of how water behaves when it freezes), however they could also be part of an impact melt drainage network.

LROC WAC mosaic with arrow noting the location of the melt › View larger image
LROC WAC mosaic with arrow noting the location of the melt features within Tycho crater seen in the NAC image above. Image width is 150 km [NASA/GSFC/Arizona State University].