Finsch crater AS17-P-2335

Forfatter/Opretter:

NASA

Kredit:

Arizona State University, Apollo Image Archive, Apollo Browse Gallery, Apollo 17 Panoramic Camera

AS17-P-2335

Shortlink:

https://dkwiki.dk/b/419c0

kilde:

Wikimedia Commons

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1440 x 1200 Pixel (747131 Bytes)

beskrivelse:

Oblique view facing north of Finsch crater in Mare Serenitatis, the moon. This image is based on to Figure 242 of Apollo Over the Moon: A View from Orbit (NASA SP-362), which has the following caption:

This picture, showing an area in central Mare Serenitatis 200 km from the nearest outcrops of terra rocks, is an oblique view of a 4-km diameter crater form about 200 m deep. The crater floor is similar to the surface of the surrounding mare, which is presumably mare basalt covered by 3 to 6 m of regolith. The rim of the crater is raised, although subdued; from this we infer that the present form was developed when mare lava flooded a normal impact crater that had formed on a lower, preexisting surface. The flooding basalt then subsided, more or less in proportion to its thickness, which was greatest inside the crater. The subsidence may have resulted from escape of bubbles from the lava while it was soft, thermal contraction of the lava, and compaction of an underlying relatively loosely packed regolith. Regolith compaction may have occurred when the load and heat of the flooding lava crushed irregular fragments of regolith into more compact shapes and plastically deformed the glassy components of the regolith into more compact shapes or into voids between other particles.

R. J. Pike's (1972) data on the rim heights of lunar craters 90 m to 10 km in diameter indicate this crater probably had a rim about 200 m high when it was buried. The lava plain around the depression presently stands about 25 m below the rim crest, giving a minimum thickness for the flooding lava of 175 m.-R.E.E.

Licens:

Public domain