Difference between revisions of "March 30, 2004"

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      <td width="50%"><h2 align="left">Silicic Domes?</h2></td>
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  <td width="50%"><h2 align="right">March 30, 2004</h2></td>
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    [javascript:;" onMouseOver="MM_swapImage('main_image','','images/LPOD-2004-03-30b.jpeg',1)" onMouseOut="MM_swapImgRestore() <IMG SRC="images/LPOD-2004-03-30.jpeg" NAME="main_image" width="534" height="400" border="0">]</div>
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      <td><div align="center" span class="main_sm">Image Credit:  <a class="one" HREF="mailto:weileong@singnet.com.sg">Tan Wei Leong</A></div></td>
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<table class="story" border="0" bgcolor="#FFFFFF" width="90%" cellpadding="10" align="center"><tr><td>
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  <p class="story" align="center"><b>Silicic Domes? </b></p>
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  <p class="story" align="left">        Lunar volcanism was pervasive, producing mare lava [../02/LPOD-2004-02-08.htm flows] and associated
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        features such as sinuous [../02/LPOD-2004-02-29.htm rilles], pyroclastic
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        [../02/LPOD-2004-02-10.htm deposits] and [LPOD-2004-03-26.htm domes]. The magmas that made
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        these features were basalts - melted mantle rocks rich in silica, oxygen, iron and magnesium. The latter two
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        elements give basalts the dark color we see in the maria. Lunar scientists have hunted for other types of
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        volcanic rocks, and these two domes near the crater Gruithuisen are the best known examples. Gruithuisen Gamma is
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        about 20 km wide and 1200 m high; Gruithuisen Delta is 13 km wide and 1550 m high. Their steep sides suggest they
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        were formed by more viscous lavas than normal mare domes such as those near [../01/LPOD-2004-01-02.htm
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        Cauchy] and [LPOD-2004-03-26.htm Hortensius]. Mathematical models of dome growth reaffirm this
 +
        idea. On Earth, lavas with similar flow characteristics to the Gruithuisen domes are rhyolites, dacites and
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        basaltic andesites - rocks with more silica and less iron and magnesium than basalts. If these lunar domes are
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        made of silica-rich magma the next question is why?
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</p>
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  <p><b>Technical Details:</b><br>
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  Date: 13th Feb, 2003 15:22UT; Moon 13 days old. Takahashi Mewlon 250 (250mm F/12 Dall Kirkham) at
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f/27, mounted on a William Optics GT-1. Philips PCVC740K ToUcam Pro used with Televue 2X Barlow.</p>
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  <p class"story"><b>Related Links:</b><br>
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[http://www.sg-planets.org/index.html H-R Lunar and Planetary Images from Singapore]<br>
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[http://www.agu.org/pubs/crossref/2003/2002JE001909.shtml Lunar Gruithuisen and Mairan domes: Rheology and mode of emplacement]<br>
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[http://www.lpi.usra.edu/research/lunar_orbiter/images/img/iv_145_h1.jpg Lunar Orbiter IV view]</p>
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  <p class"story"> <b>Tomorrow's LPOD:</b> Great Graben!</p>
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  <p><img src="../../../MainPage/spacer.gif" width="640" height="1"></p>
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  <p align="center" class="main_titles"><b>Author & Editor:</b><br>
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      [mailto:chuck@observingthesky.org Charles A. Wood]</p>
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      <p align="center" class="main_titles"><b>Technical Consultant:</b><br>
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      [mailto:anthony@perseus.gr Anthony Ayiomamitis]</p>
 +
      <p align="center" class="main_titles"><b>[mailto:webmaster@entropysponge.com Contact Webmaster]</b></p>
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      <p align="center" class="main_titles"><b>A service of:</b><br>
 +
      <a class="one" href="http://www.observingthesky.org/">ObservingTheSky.Org</a></p>
 +
      <p align="center" class="main_titles"><b>Visit these other PODs:</b> <br>
 +
      <a class="one" href="http://antwrp.gsfc.nasa.gov/apod/astropix.html">Astronomy</a> | <a class="one" href="http://www.msss.com/">Mars</a> | <a class="one" href="http://epod.usra.edu/">Earth</a></p></td>
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      </tr>
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</table>
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<p>&nbsp;</p>
  
  

Revision as of 15:37, 4 January 2015

Silicic Domes?

Silicic Domes?

March 30, 2004
[javascript:;" onMouseOver="MM_swapImage('main_image',,'images/LPOD-2004-03-30b.jpeg',1)" onMouseOut="MM_swapImgRestore() <IMG SRC="images/LPOD-2004-03-30.jpeg" NAME="main_image" width="534" height="400" border="0">]
Image Credit: <a class="one" HREF="mailto:weileong@singnet.com.sg">Tan Wei Leong</A>

Silicic Domes?

Lunar volcanism was pervasive, producing mare lava [../02/LPOD-2004-02-08.htm flows] and associated features such as sinuous [../02/LPOD-2004-02-29.htm rilles], pyroclastic [../02/LPOD-2004-02-10.htm deposits] and [LPOD-2004-03-26.htm domes]. The magmas that made these features were basalts - melted mantle rocks rich in silica, oxygen, iron and magnesium. The latter two elements give basalts the dark color we see in the maria. Lunar scientists have hunted for other types of volcanic rocks, and these two domes near the crater Gruithuisen are the best known examples. Gruithuisen Gamma is about 20 km wide and 1200 m high; Gruithuisen Delta is 13 km wide and 1550 m high. Their steep sides suggest they were formed by more viscous lavas than normal mare domes such as those near [../01/LPOD-2004-01-02.htm Cauchy] and [LPOD-2004-03-26.htm Hortensius]. Mathematical models of dome growth reaffirm this idea. On Earth, lavas with similar flow characteristics to the Gruithuisen domes are rhyolites, dacites and basaltic andesites - rocks with more silica and less iron and magnesium than basalts. If these lunar domes are made of silica-rich magma the next question is why?

Technical Details:
Date: 13th Feb, 2003 15:22UT; Moon 13 days old. Takahashi Mewlon 250 (250mm F/12 Dall Kirkham) at f/27, mounted on a William Optics GT-1. Philips PCVC740K ToUcam Pro used with Televue 2X Barlow.

Related Links:
H-R Lunar and Planetary Images from Singapore
Lunar Gruithuisen and Mairan domes: Rheology and mode of emplacement
Lunar Orbiter IV view

Tomorrow's LPOD: Great Graben!

<img src="../../../MainPage/spacer.gif" width="640" height="1">

Author & Editor:
Charles A. Wood

Technical Consultant:
Anthony Ayiomamitis

Contact Webmaster

A service of:
<a class="one" href="http://www.observingthesky.org/">ObservingTheSky.Org</a>

Visit these other PODs:
<a class="one" href="http://antwrp.gsfc.nasa.gov/apod/astropix.html">Astronomy</a> | <a class="one" href="http://www.msss.com/">Mars</a> | <a class="one" href="http://epod.usra.edu/">Earth</a>


 


COMMENTS?

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