Difference between revisions of "March 30, 2004"
(Created page with "__NOTOC__ =Silicic Domes?= ---- ===COMMENTS?=== Click on this icon image:PostIcon.jpg at the upper right to post a comment.") |
|||
| (11 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
__NOTOC__ | __NOTOC__ | ||
=Silicic Domes?= | =Silicic Domes?= | ||
| − | + | <!-- Start of content --> | |
| − | + | <table width="640" border="0" align="center" cellpadding="6" cellspacing="2"> | |
| − | + | <tr> | |
| − | ---- | + | </tr> |
| − | === | + | </table> |
| − | + | <table width="85%" border="0" align="center" cellpadding="6" cellspacing="2"> | |
| + | <tr> | ||
| + | <td colspan="2"><div align="center"> | ||
| + | {{HoverImage|LPOD-2004-03-30.jpeg|LPOD-2004-03-30b.jpeg}}</div> | ||
| + | </td> | ||
| + | </tr> | ||
| + | </table> | ||
| + | <table width="100%" border="0" cellpadding="8"> | ||
| + | <tr> | ||
| + | <td><div align="center"><p>Image Credit: [mailto:weileong@singnet.com.sg Tan Wei Leong]</p></div></td> | ||
| + | </tr> | ||
| + | </table> | ||
| + | <table class="story" border="0" bgcolor="#FFFFFF" width="90%" cellpadding="10" align="center"><tr><td> | ||
| + | <p class="story" align="center"><b>Silicic Domes? </b></p> | ||
| + | <p class="story" align="left"> Lunar volcanism was pervasive, producing mare lava [[February_8,_2004|flows]] and associated | ||
| + | features such as sinuous [[February_29,_2004|rilles]], pyroclastic | ||
| + | [[February_10,_2004|deposits]] and [[March_26,_2004|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 [[January_2,_2004|Cauchy]] | ||
| + | and [[March_26,_2004|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? | ||
| + | </p> | ||
| + | <p><b>Technical Details:</b><br> | ||
| + | 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.</p> | ||
| + | <p class="story"><b>Related Links:</b><br> | ||
| + | [http://www.sg-planets.org/index.html H-R Lunar and Planetary Images from Singapore]<br> | ||
| + | [http://www.agu.org/pubs/crossref/2003/2002JE001909.shtml Lunar Gruithuisen and Mairan domes: Rheology and mode of emplacement]<br> | ||
| + | [http://www.lpi.usra.edu/research/lunar_orbiter/images/img/iv_145_h1.jpg Lunar Orbiter IV view]</p> | ||
| + | <p><b>Yesterday's LPOD:</b> [[March 29, 2004|Hoover Dam (and Surroundings)]] </p> | ||
| + | <p><b>Tomorrow's LPOD:</b> [[March 31, 2004|Great Graben!]] </p> | ||
| + | </td></tr> | ||
| + | </table> | ||
| + | <!-- start bottom --> | ||
| + | <table width="100%" border="0" cellspacing="2" cellpadding="4"> | ||
| + | <tr> | ||
| + | <td><hr></td> | ||
| + | </tr> | ||
| + | <tr> | ||
| + | <td> | ||
| + | <p align="center" class="main_titles"><b>Author & Editor:</b><br> | ||
| + | [mailto:tychocrater@yahoo.com Charles A. Wood]</p> | ||
| + | <!-- Cleanup of credits --> | ||
| + | <!-- Cleanup of credits --> | ||
| + | <!-- Cleanup of credits --> | ||
| + | <!-- Cleanup of credits --> | ||
| + | <!-- Cleanup of credits --> | ||
| + | <!-- Cleanup of credits --> | ||
| + | <!-- Cleanup of credits --> | ||
| + | </tr> | ||
| + | </table> | ||
| + | <p> </p> | ||
| + | <!-- End of content --> | ||
| + | {{wiki/ArticleFooter}} | ||
Latest revision as of 19:14, 7 February 2015
Silicic Domes?
|
Image Credit: Tan Wei Leong |
|
Silicic Domes? Lunar volcanism was pervasive, producing mare lava flows and associated features such as sinuous rilles, pyroclastic deposits and 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 Cauchy and 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: Related Links: Yesterday's LPOD: Hoover Dam (and Surroundings) Tomorrow's LPOD: Great Graben! |
|
Author & Editor: |
COMMENTS?
Register, Log in, and join in the comments.
