[Terrapreta] More on clay/pottery etc

[Kevin Chisholm]

Dear Kurt

rukurt at westnet.com.au wrote:
> Kevin Chisholm wrote:
>> Dear Kurt
>>
>> That is a good point you raise. However, obviously, if the wood was on 
>> the surface, it would rot, but in such submerged conditions, it does 
>> indeed remain good for centuries. Is there perhaps some intermediate 
>> condition of pH and oxygen, or particular micro-organism, where the 
>> wood is "denatured" in a way that elemental carbon remains?
>>
>> Consider a peat bog... the vegetation is humified, and its blackness 
>> suggests a significant degree of carbon. Consider also the so-called 
>> "bog soils", which are definitely not "fire related", but which are 
>> indeed black... the Northern Equivalent of Brazilian Terra Preta?
>>
>> It is an interesting puzzle indeed.

> Indeed, but is there any *real* evidence of these ideas? We can 'blue 
> sky' all sorts of things, but they need to be proven to become real. 
>  From what I have see written it seems that all the charcoal in 
> terrapreta is indeed charcoal and not something "charcoal-like". Or have 
> I missed something?

It strikes me that there are a lot of "loose ends" on Terra Preta:
1: The pottery shards were explained away as being for aeration. This 
does not make sense to me, in that there is no way I can see that adding 
broken pottery to soil will enable improved oxygenation, or improved 
drainage. Far better explanations, in my opinion, include:
* The shards are from buried water jugs,
* The shards are used as a means of inoculating the TP with a desirable 
fungus.
* The shards are from broken charcoal retorts, or smudge pots.
* The shards are simply discarded broken pottery that was thrown on a 
dump, or "kitchen midden."

2: We were told that the area covered by Terra Preta in Brazil was 
greater than the area of France. It boggles my mind that an area like 
this would be covered with charcoal to depths of up to 6 feet simply to 
grow produce. See : http://www.civilization.ca/academ/articles/sway_01e.html
for an insight into bogs and their Archeological significance. If people 
started looking in Canadian Muskeg, of which there are many hundreds of 
thousands of square miles, they would probably find evidence of 
agriculture and use being made of the TP properties of Canadian bogs. If 
a Brazilian Aboriginal went on a long walk-about to another area and saw 
others growing great crops in black soil associated with bogs, he would 
probably want do the same in his area. He wouldn't have to be a genius 
to figure out that charcoal makes things black, and it would be a very 
simple advancement for him to mix some charcoal with local soil, to see 
if his crops improved.

3: While SOME TP areas were identified as being from man-made charcoal, 
we can ask the questions:
a: Is ALL TP made from man-made charcoal?
b: Are we assuming that because some of the TP sites contained man made 
charcoal that natural "black earth sites", such as would be found in 
humified bogs would not qualify as TP sites?

I would suggest that there are still enough "loose ends" associated with 
TP that its origin and evolution are far from being "cast in stone."

Best wishes,

Kevin
> 
> Kurt
> 
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