Friday, May 14, 2010

Regolith patterns in Mendel-Rydberg ROI

Regolith patterns in the Mendel-Rydberg Constellation Region of Interest (51.14°S, 266.93°E), from Lunar Reconnaissance Orbiter (LRO) Narrow-Angle Camera (LROC NAC) M118090761LE; field width = 0.64 km [NASA/GSFC/Arizona State University].

Peter Thomas
LROC News System

Regolith detail in the Constellation region of interest Mendel-Rydberg. Much of this region of interest is located in a terrain known as a "cryptomare." Cryptomaria are mare basalt volcanic deposits obscured by superposed materials usually of higher albedo. The obscuring materials are typically the ejecta of later-forming craters and basins, which blanket the older mare basalt. In the case of Mendel-Rydberg, much of the material covering the older mare may have been ejecta from the Orientale basin-forming impact event, which occurred hundreds of kilometers to the north.

The covering by ejecta of varying compositions, thicknesses, and albedos complicates the task of making an inventory of the amounts, composition, and history of lunar volcanism, and thus cryptomaria are of high scientific interest (see also the Balmer Basin region).

LRO (LROC) Wide-Angle Camera monochrome context image showing the Mendel-Rydberg Constellation Region of Interest and approximate location (arrow) of the Narrow-Angle Camera detail above. The smooth region to the west (left) of the arrow is the Mendel-Rydberg cryptomare. LROC WAC M118104209ME, click here for the full scene, 118 km across [NASA/GSFC/Arizona State University].

The full-resolution NAC view above illustrates the complexity of the highlands surface in the eastern portion of the Constellation region of interest. Here the cover of fragmentary material, or "regolith," displays the so-called "elephant skin" texture (also seen here and here) which is probably the result of slow movement involving thermal cycles of the lunar day-night and seismic shaking from meteorite impacts. The high resolution LROC images and accurate topographic information will help sort out the causes of this long-known surface characteristic of parts of the lunar surface.

Browse the full-resolution NAC image here.

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