Re: RATE Vol. II

Thanks, Phil. That makes sense. Should plate tectonics therefore be on the checklist of necessary conditions as people study planetary astronomy and look for life bearing planets?
Randy

P.S. By the way, the comment on carbon reminds me of another jaw-dropping comment in the RATE Vol. II book. Baumgardner has his chapter on trace amounts of carbon-14 in "old" organic rocks but there isn't enough of it for him. He gets dates of 50,000 years old which is too old. Then he notices that based on all the fossil data, the total number of organisms that have ever lived is enormous. Since they all lived simultaneously just prior to the Flood, the carbon level required to support that life must have been 500 times greater than it is now. However, carbon-14 would have been at the same level as it is today since it is produced from cosmic ray neutrons encountering nitrogen atoms. Therefore the ratio C-14/C-12 was 500 times lower, and voila the age becomes the correct value of 5,000 years. Unfortunately I can't find his explanation of how the accelerated plate tectonics during the Flood managed to do the isotope separation and entrap the carbon-12 but not the carbon-14.
  ----- Original Message -----
  From: Philtill@aol.com
  To: alexanian@uncw.edu ; asa@calvin.edu
  Sent: Friday, May 19, 2006 5:21 PM
  Subject: Re: RATE Vol. II

  In a message dated 5/19/2006 5:11:07 PM Eastern Daylight Time, alexanian@uncw.edu writes:
    Why is plate tectonics necessary for a planet to
    sustain life?
  I think the idea behind this is that sooner or later many of the necessary resources for life wash completely into the oceans and so there could be no way to have life on the land (or in some cases extensive life in the oceans, either) if these were not recycled and re-surfaced through plate tectonics.

  Example: carbon in the form of carbon dioxide gets bound up into carbonates by little ocean critters, and these sink to the bottom when the critters die forming massive carbonate banks like Florida and the Bahamas. Eventually the carbonates get subducted due to plate tectonics and released back into the atmosphere through volcanism. Then new life forms have access to the carbon through carbon dioxide. You and I depend on this because we get the carbon by eating the plants that got them out of the atmosphere (which in turn got them from the volcanoes...) This part of the carbon cycle makes life possible on Earth over long periods of time.

  Not being an expert on this, I can't personally vouch for these arguments, but they seem reasonable to me. I know that some planetary scientists (Kastings?) have argued that this aspect of the carbon cycle helps maintain global temperatures over long-aged wavelengths, because temperatures regulate life and life regulates carbonate deposition which feeds back into greenhouse gases released through volcanism. Hence, it forms a self-regulating closed-loop. But without plate tectonics the loop would not be closed.

  Phil Metzger
  Orlando, FL
Received on Sat May 20 09:07:00 2006