Saturday, May 21, 2011

Crater in Mare Humorum

This crater, located in Mare Humorum, is relatively fresh and very bouldered. LROC Narrow Angle Camera (NAC) M157851844LE, LRO orbit 8396, April 19, 2011; field of view is 500 meters. See the full-size Featured Image HERE [NASA/GSFC/Arizona State University].

Drew Enns
LROC News System

Why is this crater so bouldered?

Bouldery craters are primarily the result of bolides impacting solid material. More cohesive materials produce larger boulders when they are impacted. Craters like these can give clues as to the thickness of the regolith. As craters increase in diameter, they excavate further into the surface. So if a crater has no boulders, it has probably excavated only regolith. This impact though has punched through the overlying regolith and fragmented the underlying mare basalt into large boulders.

An intermediate view of the subject crater belies the loss of granularity in what only appears to be the relatively smooth background of the basin floor in the LROC Wide Angle Camera (WAC) contextual view below. In high sun myriad far older craters of similar size are visible [NASA/GSFC/Arizona State University].

LROC WAC context image of the LROC Featured Image, May 20, 2011. It's field of view is the white square in this 100 km-square scene. See the full-size context image HERE [NASA/GSFC/Arizona State University].

Can you find the transition between unbouldered and bouldery craters in the full LROC NAC!

Related Posts:
Bouldery crater near Mare Australe
Fresh crater on Oceanus Procellarum
Buckland Boulders

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