LROC: Veneer of Melt

A veneer of impact melt rock erodes away the surface just north of Newcomb crater in the lunar highlands. A 406 meter-wide field of view from LROC Narrow Angle Camera (NAC) frame M162026367LE, LRO orbit 9012, June 6, 2012; angle of incidence 73.95° over 0.91 meter per pixel resolution, from 43.88 kilometers. (View the 700 meter-wide field of view shown in the LROC Featured Image, released September 14, 2012, HERE.) [NASA/GSFC/Arizona State University].

Drew Enns
LROC News System

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 the area shown at high-resolution in the LROC Featured Image, a veneer of melt located on Newcomb's northern ejecta blanket. Note the large smooth surfaces on the crater's floor. LROC Wide Angle Camera (WAC) 100 meter resolution Global monochrome mosaic, field of view 100 kilometers across. [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 Newcomb, crater in the full LROC NAC frame, HERE.

Related Posts:
Boulder on the Edge
Splish Splash
An Impact Melt Veneer in the Highlands
King crater's unusual melt pond

Simulated view of the same WAC mosaic above draped over LOLA 128 point-per-degree elevation model (v.2) from a perspective 10 km over the eastern side of Newcomb, looking northwest. ILIADS application, NASA LMMP.

A more recent look, from a higher altitude (147.13 km), shows the erosion of melt in context with local topography, especially three distinct melt ponds north of Newcomb. LROC NAC frame M180887966R, spacecraft orbit 11774, January 11, 2012; incidence angle 72.63° at 1.46 meters resolution [NASA/GSFC/Arizona State University]/