LPOD May 5, 2008
image by Stefan Lammel, Uxbridge, England
Every piece of maria on the Moon was laid down as a lava flow. And almost every one of those flows has been eroded by constant gardening by small meteorite impacts so that their edges are invisible. This area in western Mare Imbrium is famous for having the best preserved lava flows. To maximize their visibility I have strongly enhanced Stefan's original image. The largest flow is in the upper right but most of the flows are narrower and run from the bottom left toward the upper center. The relationship between the flows and the mare ridges is uncertain. Two flows seems to be stopped by the Heim ridge, implying that the ridge existed before the flows were active. The large flow on the left appears to have its source south of the Zirkel ridge and its snout to the north of it, suggesting that the ridge was formed after the flow. There are excellent Apollo images of this area, and a handful of previous amateur views so the relation of flows to ridges can be examined under different lighting conditions.
Chuck Wood
Technical Details
16-Feb-08 21:22UT. 10in f4.8 Newtonian, Infinity 2-1M, 4x PowerMate, green filter, 700/2500, MAP: 18x128, Registax V4, PSE 5, Focus Magic
Related Links
Rükl plates 9, 10, 19 & 20
Stefan's website
COMMENTS
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(1) Sryx, can't see the picture. But am a reading guy anyway ;)
(2) Sorry - I was having trouble last night and could not complete this LPOD then, finished it this AM.
--Chuck
(3) So if the flow came after the Zirkel ridge what forces caused the ridge? Could the impact of Lambert help to make it? Aethrae, Andrew Martin SFO
(4) Because mare ridges usually help define a concentric circle within a basin they must be due to more than just a local event such as an impact. The ridges are thought to form from the weight of the lava piles that cause the basin floor to subside and the lavas have to fit within a smaller volume.
--Chuck
