Friday, March 11, 2011

LROC: Right Angle

A section of a lobate scarp inside Karrer crater. Frame from LROC Narrow Angle Camera (NAC) Science Mission observation M145557281R, LRO orbit 6584, November 28, 2010; solar illumination incidence is 71° at a corrected resolution of 64 centimeters per pixel. See a full-size view of the Featured Image HERE [NASA/GSFC/Arizona State University].

Sarah Braden
LROC News System

Karrer (52.13°S, 142.31°W) is mare-filled crater on the far side of the Moon, approximately 51 km in diameter. Karrer is special because there are fewer mare basalt surfaces on the far side compared to the near side of the Moon.

Within Karrer crater's mare basalt covered floor is a lobate scarp, unofficially designated as Karrer scarp for the crater within which it is located. Today's image shows a section of this scarp, where the deformation of the mare basalt is close to forming the shape of two right angles. Mare basalt surfaces often have lobate scarps and wrinkle ridges, two types of contractional tectonic features. In the WAC monochrome mosaic (below), you can see that the scarp extends south outside the rim of Karrer crater onto highlands material. Lobate scarps are thought to be the surface expression of thrust faults, formed when an upper fault block is pushed up and over a lower fault block.

LROC Wide Angle Camera (WAC) 100 meter per pixel monochrome mosaic of the mare-filled crater Karrer. The lobate scarp runs approximately north-south through the crater's interior basin. For a full-sized view of this contextual image, click HERE [NASA/GSFC/Arizona State University].

As LRO's Science Mission observation become available, an opportunity presents itself to gather further observations of a target area, courtesy of the LROC team and the Planetary Data System. The WAC view above of Karrer's interior, for example, was swept up at the same time as the Featured Image, November 28, 2010 [NASA/GSFC/Arizona State University].

Stepping back in pixel depth brings Karrer and its immediate vicinity into view, in this monochrome (604nm) mosaic stitched together from six orbital passes, during which time the lunar surface rotated eastward under LRO's 54 km-high orbit, at that time [NASA/GSFC/Arizona State University].

Even at a simulated perspective of 12 kilometers over the mosaic, draped on the lunar digital elevation model available to users of Google Earth (version 5 and higher), the south rim of Karrer is16 km below. Situated on the eastern side of ancient and deep South Pole-Aitken basin, not far from the Apollo basin, Karrer's rim is 4100 meters below mean lunar elevation.

Browse the full NAC frame to see other parts of this lobate scarp.

Related Images:
Slipher Crater: Fractured Moon in 3-D
Aiken Crater Constellation Program ROI
The Moon in 3D

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