Results 1 to 3 of 3
  1. #1
    Widdekind's Avatar
    Widdekind is offline SUPER GIANT
    Points: 14,643, Level: 83
    Level completed: 41%, Points required for next Level: 207
    Overall activity: 0%
    Join Date
    Dec 2008
    Posts
    829
    Points
    14,643
    Level
    83
    Thanks
    42
    Thanked 247x 177 Posts

    Default Moon Volcanism ceased ~3 billion years ago



    Lunar Radar Sounder Observations of Subsurface Layers Under the Nearside Maria of the Moon -- Ono et al. 323 (5916): 909 -- Science

    ... Radar sounding from the Kaguya spacecraft has revealed subsurface layers at an apparent depth of several hundred meters in Nearside Maria. Comparison with the surface geology in the Serenitatis basin implies that the prominent echoes are probably from buried regolith layers accumulated during the depositional hiatus of mare basalts. The stratification indicates a tectonic quiescence between 3.55 and 2.84 billion years ago; mare ridges were formed subsequently. The basalts that accumulated during this quiet period have a total thickness of only a few hundred meters. These observations suggest that mascon [Mass Concentration*] loading did not produce the tectonics in Serenitatis [Basin]after 3.55 billion years ago. Global cooling probably dominated the tectonics after 2.84 billion years ago.
    TRANSLATION (?): After 3.55 billion years ago, Nearside Volcanism (Basaltic Eruptions) wound down dramatically, amounting to merely a "few hundred meters" of Basalt deposits, over the ensuing 700 million years.

    After 2.84 billion years ago, all Volcanism essentially ceased.

  2. #2
    Widdekind's Avatar
    Widdekind is offline SUPER GIANT
    Points: 14,643, Level: 83
    Level completed: 41%, Points required for next Level: 207
    Overall activity: 0%
    Join Date
    Dec 2008
    Posts
    829
    Points
    14,643
    Level
    83
    Thanks
    42
    Thanked 247x 177 Posts

    Default

    Long-Lived Volcanism on the Lunar Farside Revealed by SELENE Terrain Camera -- Haruyama et al. 323 (5916): 905 -- Science

    Most mare volcanism that formed mare deposits on the lunar Farside ceased at 3.0 billion years ago, suggesting that mare volcanism on the Moon was markedly reduced globally during this period. However, several Mare deposits at various locations on the lunar Farside also show a much younger age, clustering at 2.5 billion years ago. These young ages indicate that Mare volcanism on the lunar Farside lasted longer than was previously considered and may have occurred episodically.
    CONCLUSION (?): In the main, Mare Volcanism on the Farside ceased about 3.0 billion years ago, about 150 million years sooner than the Nearside. This is consistent w/ claims that the Farside Crust is older, and thicker, than the Nearside's, perhaps from Tidal Effects from the Earth*.

  3. #3
    Widdekind's Avatar
    Widdekind is offline SUPER GIANT
    Points: 14,643, Level: 83
    Level completed: 41%, Points required for next Level: 207
    Overall activity: 0%
    Join Date
    Dec 2008
    Posts
    829
    Points
    14,643
    Level
    83
    Thanks
    42
    Thanked 247x 177 Posts

    Default

    Mantle Plumes, which make massive eruptions, must be materials both hotter and lighter, to move up and reach the crust. Given the Gravity of the Earth, perhaps the Moon's Mantle Plumes, which erupted about 2.5 billion years ago, were tidally induced towards the Far Side. Indeed, the lighter Lunar Crust is much thicker on the Far-Side, so clearly lighter materials moved preferentially away from the Earth.

 

 

Similar Threads

  1. Replies: 1
    Last Post: 07-24-2008, 10:31 AM
  2. Given that Earth is some 5 billion years old,?
    By thequeen_jacqui in forum Earth Forum
    Replies: 0
    Last Post: 07-10-2008, 03:11 AM
  3. Is the earth really 2.19 Billion years old?
    By heady in forum Earth Forum
    Replies: 2
    Last Post: 05-30-2008, 05:00 AM
  4. Replies: 6
    Last Post: 05-14-2008, 05:32 PM
  5. Star is found to be 13.2 billion years old
    By Klaatu in forum Amateur Astronomy Forum
    Replies: 2
    Last Post: 05-12-2007, 05:01 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 05:45 AM.