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Now that very high resolution imagery of the Moon's whole north, above 60oN, can be viewed on one giant awesome zoomable map, I've been taking a close look at a number of craters. Anaxagoras sticks out to me as odd. Here is a photo of the width of the crater, roughly 45 km across, from the gigapan site linked above:

floor of Anaxagoras crater showing mountains, ridges, and collapsing walls

And here are images of a couple of details, the top one taking in an area about 5 km wide, the bottom one about 12 km:

sinuous gullies in crater wall

impact melt field full of cracks and ripples, ejecta on hills

And a topographic image, where the red areas are about 10 km higher than the pink areas:

topographic map of Anaxagoras crater

From the sharp lines of the crater wall, I've gathered that this crater is young. Also because rays of ejecta extend from it, though not of bright material like Tycho. Those rays are a bit more visible in the LMMP version of this same map.

These are my confusions:

  • Why are there mountains over the entire floor of the crater, not just in the center like usual? Associated with that, how can there be such large ridges on the south-west wall of the crater?

  • How can all the hills and mountains be covered by gigantic boulders (one pixel is about 2 m so a lot of those boulders have got to be 30 m across), while the melt plains have almost none? Wasn't it the impact that produced both the boulders and the melt?


    Notes: Because this crater is so close to the north pole, the sun here is casting long shadows that fall to the north of everything, making it look lit from below.

All data is from the Lunar Reconnaissance Orbiter, which can also be explored at the Lunar Orbital Data Explorer site, as well as at the sites linked above.

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    $\begingroup$ You might point out that the images are lit from below, which is just unusual enough that it can take some active concentration to see the relief correctly rather than thinking it's inverted. :) $\endgroup$ – Russell Borogove Jun 26 '15 at 1:04
  • $\begingroup$ Here's that same zoomable map from the first three images in the question that's centered on Anaxagoras (73.48°N 10.17°W). The topographic image was made with Planetary Data System Geosciences Node Lunar Orbiter Data Explorer using LRO LOLA Topography (altimetry data) + Lunar Orbiter Global Digital Mosaic (morphologic map). $\endgroup$ – TildalWave Jun 26 '15 at 1:47

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