Difference between revisions of "December 22, 2007"

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<p>[[File:Gassendi-5-177_medLPOD.jpg|Gassendi-5-177_medLPOD.jpg]]<br />
 
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<p>[[File:Gassendi-5-177_medLPOD.jpg|Gassendi-5-177_medLPOD.jpg]]<br />
 
 
<em>Lunar Orbiter V-177M image from[http://www.lpi.usra.edu/resources/lunarorbiter/mission/?5  LPI Lunar Orbiter Photo Gallery]</em></p>
 
<em>Lunar Orbiter V-177M image from[http://www.lpi.usra.edu/resources/lunarorbiter/mission/?5  LPI Lunar Orbiter Photo Gallery]</em></p>
 
<p>For decades I have wondered how mare lava got onto the southernmost floor of Gassendi. Like Fracastorius, Gassendi was formed on a tilted basin floor. Mare Nectaris overflowed the low rim of Fracastorius, leaving a lava-filled breached crater. At Humorum, the flooding did not quite overtop the low southern rim of Gassendi, but there is essentially identical mare material inside and outside the rim. From terrestrial images it often seems that small shadows suggest that the rim may have a narrow pass that allowed Humorum lavas to pour in. But this Lunar Orbiter V image from 40 years ago, which I don&#8217;t remember ever seeing, shows that the rim is unbroken - the lavas did not flow into Gassendi from Mare Humorum. Fractures created by the impact that formed Gassendi must have provided the conduits that allowed magma generated at depth - probably in the same magma chamber that fed Mare Humorum - to rise upward and erupt onto the crater&#8217;s floor. </p>
 
<p>For decades I have wondered how mare lava got onto the southernmost floor of Gassendi. Like Fracastorius, Gassendi was formed on a tilted basin floor. Mare Nectaris overflowed the low rim of Fracastorius, leaving a lava-filled breached crater. At Humorum, the flooding did not quite overtop the low southern rim of Gassendi, but there is essentially identical mare material inside and outside the rim. From terrestrial images it often seems that small shadows suggest that the rim may have a narrow pass that allowed Humorum lavas to pour in. But this Lunar Orbiter V image from 40 years ago, which I don&#8217;t remember ever seeing, shows that the rim is unbroken - the lavas did not flow into Gassendi from Mare Humorum. Fractures created by the impact that formed Gassendi must have provided the conduits that allowed magma generated at depth - probably in the same magma chamber that fed Mare Humorum - to rise upward and erupt onto the crater&#8217;s floor. </p>
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Rükl plate 52</p>
 
Rükl plate 52</p>
 
<p align="center"><em>Get ready for Christmas giving and support LPOD when you buy ANYTHING from Amazon thru [http://www.lpod.org/?page_id=591 LPOD!]</em></p>
 
<p align="center"><em>Get ready for Christmas giving and support LPOD when you buy ANYTHING from Amazon thru [http://www.lpod.org/?page_id=591 LPOD!]</em></p>
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===COMMENTS?===  
 
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Revision as of 18:01, 4 January 2015

Unnecessary Mystery

Gassendi-5-177_medLPOD.jpg
Lunar Orbiter V-177M image fromLPI Lunar Orbiter Photo Gallery

For decades I have wondered how mare lava got onto the southernmost floor of Gassendi. Like Fracastorius, Gassendi was formed on a tilted basin floor. Mare Nectaris overflowed the low rim of Fracastorius, leaving a lava-filled breached crater. At Humorum, the flooding did not quite overtop the low southern rim of Gassendi, but there is essentially identical mare material inside and outside the rim. From terrestrial images it often seems that small shadows suggest that the rim may have a narrow pass that allowed Humorum lavas to pour in. But this Lunar Orbiter V image from 40 years ago, which I don’t remember ever seeing, shows that the rim is unbroken - the lavas did not flow into Gassendi from Mare Humorum. Fractures created by the impact that formed Gassendi must have provided the conduits that allowed magma generated at depth - probably in the same magma chamber that fed Mare Humorum - to rise upward and erupt onto the crater’s floor.

Chuck Wood

Related Links:
Rükl plate 52

Get ready for Christmas giving and support LPOD when you buy ANYTHING from Amazon thru LPOD!


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