[Terrapreta] Long term durability of Low Temp Chars

[Sean Barry]

Hi AJH


Carbon dating of "chunks" of charcoal still in the soil can tell about the surviving "fixed" carbon in the charcoal vs other organic carbon matter.
EPRIDA has scanning electron micrographs of charcoal bits from Terra Preta.  It still shows the structure of the original cell walls from the plant that was pyrolyized to make the charcoal.  That same charcoal bit is dated back 2500+ years.  I don't think that it is doubted that anything less than a very high percentage of the original charcoal matter that was put into the soil over some thousands of years ago, is not still there.

SKB
  ----- Original Message ----- 
  From: AJH<mailto:list at sylva.icuklive.co.uk> 
  To: still.thinking at computare.org<mailto:still.thinking at computare.org> 
  Cc: terrapreta at bioenergylists.org<mailto:terrapreta at bioenergylists.org> 
  Sent: Thursday, April 26, 2007 4:28 PM
  Subject: Re: [Terrapreta] Long term durability of Low Temp Chars


  On Thu, 26 Apr 2007 15:19:17 -0600, Duane Pendergast wrote:

  >I suspect that archeologists could develop some conclusions from layers
  >built up over the centuries and carbon 14 content of remaining char. I think
  >I've seen some papers along those lines but have no references right at
  >hand. I also recall seeing some references that indicate the char can last a
  >very long time - into the thousands of years.

  Hi Duane

  I'm sure carbon 14 dating can tell us some things, despite not really
  knowing how this method copes with changes in solar activity or
  atmospheric CO2 concentrations, but can it tell us whether the
  surviving carbon in the terra preta soil started out as fixed carbon
  in biochar or oxygenated hydrocarbons bound within a char matrix?

  AJH


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