Wednesday, April 24, 2013

Getting Cracked at Weiner F

An impact crater is caught in the process of disintegration, barely visible today on the complex terrace of Weiner F crater (40.881°N; 150.608°E). LROC Narrow Angle Camera (NAC) frame M169574198L, spacecraft orbit 10124, September 2, 2011. Illumination angle of incidence 46.95° from the southwest, resolution reduced from the original 43 cm per pixel from 30.02 km [NASA/GSFC/Arizona State University].
James Ashley
LROC News System

This small impact crater happened to form just a little too close to the widening edge of the Wiener F crater. Fault-slumping of the upper wall of Wiener F has cracked it along a series of linear, subparallel fractures, and the whole area appears to be in the process of down-slope migration. Eventually, if the process were to continue, the disintegration would be complete and the small superposed crater would no longer be recognizable.

The context images above and below show the location of this feature -- nestled within the slumping and fault-bounded eastern crater wall that has produced an irregular protrusion into the surrounding highland terrain. The occurrence of Wiener F within a former, older and larger crater is a coincidence of nature. Who says impacts cannot occur in the same place twice? Here we see three nested craters!

Context image from NAC frame, 1.3 km across; downslope to lower left [NASA/GSFC/Arizona State University].
The WAC global mosaic context image field of view approximately 48 km from west to east [NASA/GSFC/Arizona State University].
Click HERE to examine the full NAC frame. Other examples of fault-terraced crater walls can be found with Top of the Landslide, Aristarchus Spectacular!, and Post-impact Modification of Klute W.

Center crop from HDTV still centered on Weiner F, view toward the south over the farside anorthositic highland terrain from an estimated 100 km altitude in 2007. From Japan's lunar orbiter SELENE-1 (Kaguya) [JAXA/NHK/SELENE].
Other related posts:
Impact melt outside Weiner F (October 27, 2012)
Secondary melt on the rim of Weiner F (October 2, 2012)

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