[Terrapreta] More on clay/pottery
Kevin Chisholm
kchisholm at ca.inter.net
Wed May 9 18:56:07 CDT 2007
Dear Randy
Following are some "contrarian comments" for your consideration. :-)
Randy Black wrote:
>
> -----Original Message-----
> I think the reason for ceramic pieces in Terra Preta is most likely that
> the Amazonian Indians spread their garbage pits around when they moved
> their village and started another field.
If these were garbage pits, there would be more artifacts in them than
pottery shards.
And of course in the garbage
> along with all the organic wastes were broken pots. In Chapter 23 of
> Amazoinan Dark Earths
$229 :-(
it describes the size and shape of the Terra Preta
> fields and the fact that wood dwellings in the Amazon have a life of 2-4
> years and that probably when they moved dwellings they used the old
> cleared village for a new field.
The 2-4 year life stated for tropical woods is puzzling. I would have
thought that tropical woods have significant rot resistance. At any
rate, it does not make sense that they would abandon a village because
of rot, and rebuild anew elsewhere. It would be much less work to repair
the existing buildings. However, it might be possible that they would
abandon a reasonably good habitation if they had a nomadic type of
lifestyle.Perhaps they moved into an area, chopped down all the brush
and small trees for charcoal, and then when there were no more smaller
trees, then they would move on?
As Steiner described in a recent
> posting we can presume that the Indians fired their garbage pits to keep
> bugs, animals, and disease away
If they were garbage pits, there should be much more in them than
pottery shards and fine charcoal. There should be broken tools, bones
from food animals, etc. Charcoal would be irregular in size... some
would be large pieces, yet apparently there are no large pieces of
charcoal in Terra Preta fields. Additionally, if they were intentionally
fired, the charcoal recovery rate would be low, and the ash content
would be relatively high.
found that this made good dirt and they
> may have found that the ceramic pieces helped by providing aeration.
I doubt that pottery shards would provide aeration. Fine charcoal would
surround them. If anything, they would have less aeration capability
than the charcoal alone.
One
> way to confirm some of this would be to date the long Terra Preta fields
> and see if different parts are of differing ages.
3-D age mapping could tell an enormous amount. If the terra preta fields
were a disposal site for a charcoaling operation, there would be greater
depths of charcoal of the same age in depressions. If charcoal was
produced primarily for soil building, the People would level the ground
before they applied teh charcoal... it would be less costly to level the
ground than fill it with valuable charcoal produced for agricultural
purposes. I suggest they would not waste valuable charcoal filling
depressions.
Best wishes,
Kevin
>
> Randy Black
>
>
>
>
> From: terrapreta-bounces at bioenergylists.org
> [mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of
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> Subject: Terrapreta Digest, Vol 4, Issue 130
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> Today's Topics:
>
> 1. Re: commercial charcaol. (Michael Bailes)
> 2. Commercial charcoal briquettes (Janice Stettler)
> 3. Re: Commercial charcoal briquettes (Allan Balliett)
> 4. Re: More on clay/pottery etc (Michael Bailes)
> 5. Re: More on clay/pottery etc (Kevin Chisholm)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 10 May 2007 03:25:52 +1000
> From: "Michael Bailes" <michaelangelica at gmail.com>
> Subject: Re: [Terrapreta] commercial charcaol.
> To: terrapreta <terrapreta at bioenergylists.org>
> Message-ID:
> <7dcba7be0705091025u6ac5a463jd482b9aad71fa14b at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
>>
>> While in Korea last Fall I noticed an article in the paper that
> reported
>> on
>> high levels of heavy metals in charcoal fuel briquettes made from
> refuse.
>> Tom
>
>
> i agree Tom heavy metals are a problem a problem with char made from
> sewage.
>
> In Oz there is usually a distinction made between charcoal and "heat
> beads"
> that are compressed with all sorts of extraneous flamable stuff (They
> don't
> say what)
> MB
>
>
>> Subject: [Terrapreta] commercial charcaol.
>>
>> Can anyone advise does regular commercial charcoal such as
>> Kingsford have any particularly nasty materials in it as binders
>> or anything or is it acceptable to add to soil as well.
>>
>> Thank you,
>>
>> Michael; N Trevor
>> Marshall Islands
>>
>> _
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> Message: 2
> Date: Wed, 9 May 2007 10:27:46 -0700
> From: "Janice Stettler" <shibbolethf at earthlink.net>
> Subject: [Terrapreta] Commercial charcoal briquettes
> To: terrapreta at bioenergylists.org
> Message-ID: <410-22007539172746843 at earthlink.net>
> Content-Type: text/plain; charset="us-ascii"
>
> Mr. Trevor asked about commercial brands of charcoal like Kingsford.
> These products use coal dust, saw dust and charcoal in their
> formulation. While coal is carbon, it is a crystallized form without
> the necessary porosity. Saw dust sucks up nitrogen in the course of
> breaking down. Neither of these constituents are desirable.
>
>
> Tony Stettler
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>
> Message: 3
> Date: Wed, 9 May 2007 13:35:56 -0400
> From: Allan Balliett <aballiett at frontiernet.net>
> Subject: Re: [Terrapreta] Commercial charcoal briquettes
> To: shibbolethf at earthlink.net, terrapreta at bioenergylists.org
> Message-ID: <p0623091bc267b6e0fdb2@[192.168.254.4]>
> Content-Type: text/plain; charset="us-ascii" ; format="flowed"
>
> What about the 'organic' brands? The ones sold a Whole Foods, etc?
> -Allan
>
> At 10:27 AM -0700 5/9/07, Janice Stettler wrote:
>> Mr. Trevor asked about commercial brands of charcoal like Kingsford.
>> These products use coal dust, saw dust and charcoal in their
>> formulation. While coal is carbon, it is a crystallized form
>> without the necessary porosity. Saw dust sucks up nitrogen in the
>> course of breaking down. Neither of these constituents are
>> desirable.
>>
>>
>> Tony Stettler
>>
>>
>>
>> _______________________________________________
>> Terrapreta mailing list
>> Terrapreta at bioenergylists.org
>> http://bioenergylists.org/mailman/listinfo/terrapreta_bioenergylists.or
> g
>
>
>
>
> ------------------------------
>
> Message: 4
> Date: Thu, 10 May 2007 06:05:45 +1000
> From: "Michael Bailes" <michaelangelica at gmail.com>
> Subject: Re: [Terrapreta] More on clay/pottery etc
> To: "Allan Balliett" <aballiett at frontiernet.net>, terrapreta
> <terrapreta at bioenergylists.org>
> Message-ID:
> <7dcba7be0705091305s4bc573e0nf243b2d9307d4ed3 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Yes you are right. Logically,you would think if they went to the trouble
> of
> grinding up charcoal they would do the same for pottery.
> So what is the answer?
> Shards would have to be fired to some extent surely?
> Pottery made just for TP ? I don't know but would love to find out.
> I doubt that firing temps would be much higher than that needed for
> Terracotta. But I don't know.
> There may be a bit on this In Amazonian Dark Earths if you can steal a
> copy
>
> Here are a few posts I made on Hypography parent thread
> I don't know if they get us anywhere.
> mb
>
> This is from a research article translated from Portuguese a bit hard to
> follow
> http://www.scielo.br/scielo.php?pid=...pt=sci_arttext<http://www.scielo.
> br/scielo.php?pid=S0044-59672004000200004&script=sci_arttext>
>
> Quote:
> most of mineral grains were taken from fresh crystalline rocks and
> intentionally crushed and introduced into clay material as well as
> cauixi
> and cariap?.
>
> The above described minerals and organic substances led to identify the
> following materials as raw materials for the ceramics:
>
> 1) clay material derived from weathering (saprolite/mottling zone) of
> fine
> crystalline and less frequent sedimentary rocks (indicated by
> clay-derived
> minerals and iron oxy-hydroxides, anatase and quartz );
>
> 2) fresh crystalline rocks crushed (feldspars, quartz and rock
> fragments);
>
> 3) organic materials (cauixi and burned cariap?).
>
>
> The abundance of fresh feldspars, rocks fragments and roundless quartz
> indicate that coarse igneous rocks, e.g. granites, granodiorites, and
> even
> rhyolites and quartz of veins were used as temper, after crushing. It's
> possible that pre-historic Indians extracted the fresh rocks from the
> same
> place where they took the clayey saprolite.
>
> To improve the plasticity of the raw material they introduce organic
> material like cauixi and cariap?, crushed quartz, or even old ceramic
> (waste) crushed, in an old process of recycling.
>
> .http://www.scielo.br/scielo.php?scri...72004000200004<http://www.scielo
> .br/scielo.php?script=sci_arttext&pid=S0044-59672004000200004>
> ABSTRACT
>
> Several archaeological black earth (ABE) sites occur in the Amazon
> region.
> They contain fragments of ceramic artifacts, which are very important
> for
> the archaeological purpose.
> In order to improve the archaeological study in the region we carried
> out a
> detailed mineralogical and chemical study of the fragments of ceramic
> artifacts found in the two ABE sites of Cachoeira-Porteira, in the Lower
> Amazon Region.
> Their ceramics comprise the following tempers: cauixi, cariap?, sand,
> sand
> +feldspars, crushed ceramic and so on and are composed of quartz, clay
> equivalent material (mainly burned kaolinite), feldspars, hematite,
> goethite, maghemite, phosphates, anatase, and minerals of Mn and Ba.
> Cauixi
> and cariap?, siliceous organic compounds, were found too.
> The mineralogical composition and the morphology of their grains
> indicate a
> saprolite (clayey material rich on quartz) derived from fine-grained
> felsic
> igneous rocks or sedimentary rocks as source material for ceramic
> artifacts,
> where silica-rich components such cauixi, cariap? and/or sand (feldspar
> and
> rock fragments) were intentionally added to them.
> The high content of (Al,Fe)-phosphates, amorphous to low crystalline,
> must
> be product of the contact between the clayey matrix of pottery wall and
> the
> hot aqueous solution formed during the daily cooking of animal foods
> (main
> source of phosphor).
> The phosphate crystallization took place during the discharge of the
> potteries put together with waste of organic material from animal and
> vegetal origin, and leaving to the formation of the ABE-soil profile.
>
> I was wandering arround the Permaculture forums and came accross this
> post
> which is interesting.
> You should vist the site if you are into useful plants and gardening.
> It's
> great
> SEE:
> http://forums.permaculture.org.au/vi...?p=18201#18201<http://forums.perm
> aculture.org.au/viewtopic.php?p=18201#18201>
>
> Re: Terra Preta What is the fuction of the clay pottery shards?
>
> "PostPosted: Wed May 03, 2006 11:26 pm
> On reading about the actual terra preta mix and process there are a lot
> of
> questions about the presence of clay shards. I havent even read any
> speculation as to why they are there.
> Two, things spring to mind.
>
> Firstly, the ancients may have been carting this soil to other areas or
> water to that site but woven baskets would have been more feasible for
> the
> soil.
>
> Secondly and more likely, possibly part of the reason for the burning
> was
> that this was the place that clay was fired. Once a pot was broken they
> could have been smashed over time or used as 'heat beads' in the next
> firing. The refined pottery we use is fired at incredible temperatures,
> this
> may not have been known to these people and their climate was not
> condusive
> to sun drying [which can take months].
>
> Just idle speculation I doubt the ancients would have deliberately tried
> build soils but they may have been building pots and stumbled across a
> symbiosis in their process which lead to the terra preta.
>
> I would love more speculation or clarification if anyone has tracked
> down
> why the clay shards appear through this mix. The show I saw on terra
> preta
> didnt mention them, only found it in further reading.
>
> Cheers
>
> Floot
> mb
>
> On 10/05/07, Allan Balliett <aballiett at frontiernet.net> wrote:
>>> I think clays are acid while charcoal tends to be alkaline so there
>>> may be a clue thery to why it was used in TP. Like charcoal it also
>>> has adsorption properties.
>>> If anyone could point me to reach aricles wher it was used as asoil
>>> amendment i would apreciate it
>> Michael - I've received contradictory information on whether or not
>> the shards in Terra preta had been fired or not. I understood Charles
>> C. Mann to say that they were not fired and the many of the shards
>> were not from pottery but apparently made in sheets for terra preta
>> use (only). From other sources, including general archeologists I
>> hear that 'all pottery is, by definition fired"
>>
>> My 'point' here is sort of: if the makers of terra preta wanted to
>> incorporate clay for clays sake and they were already pulverizing
>> char to 1x1mm, wouldn't they as well pulverize clay (or add in in a
>> natural state) rather than include it in large pieces? Large pieces,
>> which, the vary 'largeness' of could have a function outside of
>> chemistry or nutrition?
>>
>> -Allan
>>
>
>
>
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