Revealed Surface, eastern Mare Insularum

Southern slope of unnamed fracture along the eastern mare/highland boundary of Mare Insularum. LROC Narrow Angle Camera (NAC) frame M1114199297R, LRO orbit 16439, January 30, 2013; 1147.2 meter field of view centered on 13.135°N, 355.638°E, 42.94° angle of incidence, resolution 0.96 meters per pixel from 114.18 km. (Downslope toward upper-right, north at top) [NASA/GSFC/Arizona State University].

Hiroyuki Sato
LROC News System

Today's Featured Image highlights a portion of an unnamed linear fissure located along the eastern edge of Mare Insularum, near the mare/highland boundary.

The width of this fissure varies from about 1.5 to 2 km, its  length is about 90 km, and it extends in the northwest-southeast direction.

The upper-right portion of the opening image, showing a shallow groove extending from up to middle right of the image, corresponds to the bottom of the fissure. Thus most of the image reveals the southern wall of the fissure.

The LROC Featured Image field of view rendered approximately in elevation data from the LROC WAC DTM. Local slopes in the vicinity of the fracture of interest can be difficult to otherwise see. LROC QuickMap [NASA/GSFC/DLR/Arizona State University].

On this slope, there is a high reflectance area with sinuous boundaries. This unit is hard to interpret in terms of what is on top and what is below, stratigraphically. The sunlight is from left side, highlighting what appears as a slightly raised boundary between the two units (arrows). Elsewhere it looks as if the high reflectance material overlies the lower reflectance material. Which unit is younger? Try counting craters between the two, but be careful, if the units have different hardnesses, then the more coherent unit may preserve craters better. 

Unnamed fracture running northwest to southeast on the eastern side of Mare Insularum and surrounding vicinity in LROC WAC monochrome mosaic (100 meters per pixel), centered is 13.12°N, 355.66°E. The LROC NAC footprint (blue box) and location of the field of view in the Featured Image (yellow arrow) are marked [NASA/GSFC/Arizona State University].

Since this whole area is on a slope, slope failure may have revealed an underlying immature surface. Indeed multiple higher reflectance boulders are sitting at the downslope side of this high reflectance unit. But the upper complicated shapes are difficult to explain by this simple story. Or perhaps low reflectance materials could have slumped and covered portions of the high reflectance material? A high resolution NAC DTM would help scientist unravel this complicated morphology.

Explore this enigmatic patterned surface in full NAC frame yourself, HERE.

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