Difference between revisions of "December 22, 2009"
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=Braided Rille= | =Braided Rille= | ||
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| − | <em>image from [http://wms.selene.jaxa.jp/selene_viewer/jpn/observation_mission/tc/tc_056.html Kaguya Image Gallery], copyright JAXA/Selene (north to right)</em><br /> | + | <em>image from [http://wms.selene.jaxa.jp/selene_viewer/jpn/observation_mission/tc/tc_056.html" rel="nofollow Kaguya Image Gallery], copyright JAXA/Selene (north to right)</em><br /> |
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| − | This is most bizarre rille on the Moon. Apparently first noticed on Lunar Orbiter V [http://www.lpi.usra.edu/resources/lunarorbiter/frame/?5183 images] and later [http://www.lpi.usra.edu/resources/apollo/frame/?AS15-93-12725 photographed] by Apollo 15 astronauts, this weird feature west of Gruithuisen seems to have been forgotten. This recently released Kaguya Terrain Camera mosaic brings it back to our attention. It starts (upper right) in a banana-shaped depression similar to the beginning of Hadley Rille. From this vent lava flowed downward (in this image) constructing a lava tube whose roof partially collapsed. At the rounded diamond-shaped collapse the lava flowing through the tube turned 90° and began a 40 km long slightly sinuous flow to the south (left). The oddity is the roughly alternating oval collapses and low ridges, giving the rille a braided look. At its south end the twisted rille seems continuous with a mare ridge. This suggested to Pete Schultz (<em>Moon Morphology</em>, p 408) that the elevated bits along the rille were the remnants of a mare ridge and that the oval depressions collapsed into a lava tube under the ridge. Back in the early 1970's when Pete wrote, most lunar scientists (me too) thought that mare ridges were volcanic structures. But after Apollo it became clear that most were low angle faults, perhaps with no associated volcanism. And we have learned that banana-shaped depressions are source vents for lava tubes. Sometimes in Hawaii lava erupts out of collapse pits and that may have been what happened here. The rille's relation to the mare ridge is still unclarified - is it a chance impingement or is something happening that we still don't understand?<br /> | + | This is most bizarre rille on the Moon. Apparently first noticed on Lunar Orbiter V [http://www.lpi.usra.edu/resources/lunarorbiter/frame/?5183" rel="nofollow images] and later [http://www.lpi.usra.edu/resources/apollo/frame/?AS15-93-12725" rel="nofollow photographed] by Apollo 15 astronauts, this weird feature west of Gruithuisen seems to have been forgotten. This recently released Kaguya Terrain Camera mosaic brings it back to our attention. It starts (upper right) in a banana-shaped depression similar to the beginning of Hadley Rille. From this vent lava flowed downward (in this image) constructing a lava tube whose roof partially collapsed. At the rounded diamond-shaped collapse the lava flowing through the tube turned 90° and began a 40 km long slightly sinuous flow to the south (left). The oddity is the roughly alternating oval collapses and low ridges, giving the rille a braided look. At its south end the twisted rille seems continuous with a mare ridge. This suggested to Pete Schultz (<em>Moon Morphology</em>, p 408) that the elevated bits along the rille were the remnants of a mare ridge and that the oval depressions collapsed into a lava tube under the ridge. Back in the early 1970's when Pete wrote, most lunar scientists (me too) thought that mare ridges were volcanic structures. But after Apollo it became clear that most were low angle faults, perhaps with no associated volcanism. And we have learned that banana-shaped depressions are source vents for lava tubes. Sometimes in Hawaii lava erupts out of collapse pits and that may have been what happened here. The rille's relation to the mare ridge is still unclarified - is it a chance impingement or is something happening that we still don't understand?<br /> |
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| − | <em>[mailto:tychocrater@yahoo.com Chuck Wood]</em><br /> | + | <em>[mailto:tychocrater@yahoo.com" rel="nofollow Chuck Wood]</em><br /> |
| − | (Concentric crater aficionados will want to look at the [http://wms.selene.jaxa.jp/selene_viewer/jpn/observation_mission/tc/056/tc_056_1.jpg original] Kaguya image!)<br /> | + | (Concentric crater aficionados will want to look at the [http://wms.selene.jaxa.jp/selene_viewer/jpn/observation_mission/tc/056/tc_056_1.jpg" rel="nofollow original] Kaguya image!)<br /> |
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<strong>Related Links</strong><br /> | <strong>Related Links</strong><br /> | ||
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| − | <div>You can support LPOD when you buy any book from Amazon thru [http://www.lpod.org/?page_id=591 LPOD!]<br /> | + | <div>You can support LPOD when you buy any book from Amazon thru [http://www.lpod.org/?page_id=591" rel="nofollow LPOD!]<br /> |
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===COMMENTS?=== | ===COMMENTS?=== | ||
Click on this icon [[image:PostIcon.jpg]] at the upper right to post a comment. | Click on this icon [[image:PostIcon.jpg]] at the upper right to post a comment. | ||
Revision as of 19:16, 4 January 2015
Braided Rille
image from " rel="nofollow Kaguya Image Gallery, copyright JAXA/Selene (north to right)
This is most bizarre rille on the Moon. Apparently first noticed on Lunar Orbiter V " rel="nofollow images and later " rel="nofollow photographed by Apollo 15 astronauts, this weird feature west of Gruithuisen seems to have been forgotten. This recently released Kaguya Terrain Camera mosaic brings it back to our attention. It starts (upper right) in a banana-shaped depression similar to the beginning of Hadley Rille. From this vent lava flowed downward (in this image) constructing a lava tube whose roof partially collapsed. At the rounded diamond-shaped collapse the lava flowing through the tube turned 90° and began a 40 km long slightly sinuous flow to the south (left). The oddity is the roughly alternating oval collapses and low ridges, giving the rille a braided look. At its south end the twisted rille seems continuous with a mare ridge. This suggested to Pete Schultz (Moon Morphology, p 408) that the elevated bits along the rille were the remnants of a mare ridge and that the oval depressions collapsed into a lava tube under the ridge. Back in the early 1970's when Pete wrote, most lunar scientists (me too) thought that mare ridges were volcanic structures. But after Apollo it became clear that most were low angle faults, perhaps with no associated volcanism. And we have learned that banana-shaped depressions are source vents for lava tubes. Sometimes in Hawaii lava erupts out of collapse pits and that may have been what happened here. The rille's relation to the mare ridge is still unclarified - is it a chance impingement or is something happening that we still don't understand?
" rel="nofollow Chuck Wood
(Concentric crater aficionados will want to look at the " rel="nofollow original Kaguya image!)
Related Links
Rükl plate 9
COMMENTS?
Click on this icon File:PostIcon.jpg at the upper right to post a comment.
