Veneer of Melt

A veneer of impact melt rock erodes away just north of Newcomb crater, in the lunar highlands. LROC NAC M162026367LE, image width is 700 m [NASA/GSFC/Arizona State University].

Impact melt forms in most impacts on the Moon. The melt shown here was emplaced during the impact event that produced Newcomb crater (29.76° N, 43.67° E). Rather than producing a melt pond or flow in this location, the melt here formed a thin veneer that cooled and formed a rigid crust. The melt veneer is now identifiable thanks to a thin scarp along its margin with boulders breaking from it. Two cracks split a small crater on the melt veneer, indicating the crater formed after the melt solidified. A larger crater is less pronounced, so perhaps it was covered by the melt as it was deposited. But how was this thin deposit of melt originally emplaced?

Newcomb crater is in center in this context image. The arrow points to today's Featured Image, a veneer of melt located on Newcomb's ejecta blanket. Note the large smooth surface on the floor of the crater - this surface is the top of a  once pond of melt that cooled into solid slab. Image width is 100 km [NASA/GSFC/Arizona State University].

Most impact melt normally stays inside a crater, forming flows and ponds on terraces, and resulting in flat floors. Often, a small portion of the melt is sloshed out of the crater and forms spectacular forms on the ejecta blanket. Some of the ejected melt flows down the flanks until it finds a depression and pond. But not all of the melt makes it to the depression as some melt solidifies on the slope. The result is a thin film of impact melt covering the shallow slopes of the crater flank, like we see in the today's Featured Image!

Explore more impact melt inside and outside of Newcomb crater in the full LROC NAC

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Posted by Drew Enns on September 14, 2012 10:05.