Elongated Crater

Full resolution LROC NAC M155084711R showing the northeastern wall and floor of Arago E crater. The floor is peppered with rocks that tumbled down the crater wall. In this image North is up, image width is ~0.5 miles (800 m) [NASA/GSFC/Arizona State University].

Arago E (8.5°,22.71°) is an elongated crater located in Mare Tranquillitatis, site of the first Apollo landing, Apollo 11! Arago E is nestled between two wrinkle ridges (see WAC context image below), which are tectonic features formed by deformation of the basaltic rocks that make up the lunar maria. Massive maria lavas placed an extra load on the surface, these deformations are adjustments of the surface due to the unrelenting force of gravity buckling the rock.

LROC WAC morphologic map showing a portion of Mare Tranquillitatis.  Arago E is nestled between two wrinkle ridges. The width of this image is  ~230 miles (370 km) [NASA/GSFC/Arizona State University].

This crater's elongated shape is perhaps due to an oblique impact, which impart excess horizontal momentum into the surface leaving an elongated shape. However, for this to happen it is thought that a projectile had to be coming in less than just 30° above the horizon. Volcanic vents can also display elongated shapes, but they don't exhibit raised rims and usually lack a flat floor, both features are seen in this crater.

LROC NAC mosaic M155084711R and L of Arago E crater, the width of this craters is ~3.7 miles (6 km) [NASA/GSFC/Arizona State University].

A picture of this crater was taken from orbit during the Apollo 15 mission.  How does the LROC at full resolution NAC compare?

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Published by Raquel Nuno on 1 May 2014