Making a Splash at King Crater

Melt Ponds at King Crater
Impact melt ponds adorn the lumpy terraces of King crater. If you look carefully, you can see small fractures in some of the these ponds. LROC NAC mosaic (M1159315479L/R), image width is approximately 8 km [NASA/GSFC/Arizona State University].

In the image above, impact melt pooled among the terraces in the walls of King Crater, a complex Copernican crater on the lunar farside. Impact melt is generated when kinetic energy associated with an impact is transferred to the target rock. Shock waves cause the rock to melt nearly instantaneously. The impact melt is flung all over the interior of the crater and some even makes it out of the crater.  Melt splashed on the crater walls tends to drain back down pooling on ledges. This downward flow resulted in a coating of impact melt called a veneer, visible in this region, along with other features like fractures. Fractures in impact melt rocks can be the result of tectonic stresses and cooling and contracting of the impact melt. Sometimes craters also form before the impact melt has fully solidified, resulting in oddly shaped craters that resemble craters that form when pebbles are thrown into mud.

Upon closer inspection, these impact melt ponds display the aforementioned fractures (center) and oddly shaped craters. LROC NAC mosaic of King crater. Image width is approximately  1 km [NASA/GSFC/Arizona State University].

Aside from its rather peculiar central peak, King is rather unique in that the impact melt is not evenly distributed around crater, but rather accumulated in the north-northwest region outside the crater rim. This may be the result of an oblique impact. In the case of an oblique impact, impact melt is concentrated downrange of the incoming projectile.

WAC context image of King Crater
LROC WAC context image of King crater (76 km) with its main melt pond to the northwest. Today's Featured Image is denoted by the yellow box. Image width is approximately 120 km [NASA/GSFC/Arizona State University].

Impact melt forms many exquisite features on the lunar surface such as flows, lobes, pits, fractures, channels, polygonal patterns, and more. Explore the impact melt features of this region in the full NAC mosaic below!

Related Posts:

Anomalous Mounds on the Floor of King Crater

King Crater's Unusual Melt Pond

Rippled Pond

Jackson's Complexity

Anaxagoras Exterior Melt 

Herigonius K Impact Melt Flow

Published by H. Meyer on 29 July 2014