Hello -- I too have found wood that looks vitrified in samples from Balkan
/ Eastern Mediterranean contexts. It is often olive, as Julie noted, but I
have also seen this in oak charcoal.
I had thought this was due to fluxing of
silicates already present in the wood under conditions of high heat, but
Linda's comment and others raise the question of secondary burning as
possibly being more important.
Regarding phytoliths in wood, I have read that while taxa such as
Salicaceae and Rosaceae are low in phytoliths, other taxa (some Fagaceae,
Pinaceae, Ericaceae) do have abundant phytoliths. It seems that there
have been few studies of dicotyledonous wood phytoliths, so maybe the
verdict is still out or there isn't a one-wood-fits-all answer?
Carnelli et al. 2004 have a nice article about alpine forest phytoliths in
Review of Paleobotany and Palynology 129:39-65 that has excellent SEM's of
several woody taxa.
Best regards,
Susan
Susan E. Allen
Department of Archaeology
675 Commonwealth Ave.
Boston University
Boston, MA 02215
tel. (617)353-3415
fax. (617)353-6800
On Thu, 26 Aug 2004, Linda Scott Cummings wrote:
> We also see this phenomenon in charcoal samples. We have done some
> experimentation and note the same result (glassy look) when we burn
> green wood at a high temperature. We get this result the first time
> we burn the wood, so reburning appears not to be necessary. Perhaps
> it is due to the presence of sap when the wood burns. There are not
> enough phytoliths in most wood to result in this look.
>
> Linda Scott Cummings
>
> >Hello, I have seen that glassy look in charcoal from the
> >"destruction level" at Gordion...the wood is pine, from beams burned
> >in a very hot fire (i.e., hot enough to deform the pottery, too, and
> >some of the wheat and lentils also have a gray look). I wonder ...
> >are there phytoliths in wood (i.e., silica) that might vitrify at
> >high temperature?
> >
> >Naomi.
> >
> >On Thursday, August 26, 2004, at 09:54 AM, Owen Davis wrote:
> >
> >>I find these in westernUSAarcheological samples, too. Here,
> >>charcoal for specialists probably isn't the answer. But, perhaps
> >>they might indicate burning of charcoal from an earlier fire -
> >>repeated use of a hearth. I have also thought the glassy appearance
> >>might result from high-temperature combustion.
> >>
> >>
> >>
> >>Yes, experimentation is the best idea.
> >>
> >>
> >>
> >>Owen.
> >>
> >>
> >>
> >>-----Original Message-----
> >>From: The archaeobotany mailing list
> >>[mailto:[log in to unmask]] On Behalf OfVan Der Veen, Dr
> >>M.
> >>Sent: Thursday, August 26, 2004 4:42 AM
> >>To: [log in to unmask]
> >>Subject: Re: deformed charcoal
> >>
> >>
> >>
> >>I have found this in my Egyptian material (Mons Porphyrites and
> >>Mons Claudianus), in press.
> >>
> >>This is likely to happen when charcoal, rather than wood is used
> >>for fuel, ie material is fired twice (usually specialist use of
> >>fuel, in my case in smithies associated with stone quarries)
> >>Though experimentation would be good idea to test this idea.
> >>
> >>
> >>
> >>Marijke van der Veen
> >>
> >>-----Original Message-----
> >>From: The archaeobotany mailing list
> >>[mailto:[log in to unmask]]On Behalf OfBIAX Consult
> >>Sent: 26 August 2004 10:48
> >>To: [log in to unmask]
> >>Subject: deformed charcoal
> >>
> >>Dear botanists,
> >>
> >>
> >>
> >>I am an archaeologist and am involved in wood and charcoal research
> >>in the Netherlands. Regularly I come upon the phenomenon in
> >>charcoal, that the cell walls of the wood seem to have melted and
> >>the cell structure has disappeared . These charcoal fragments have
> >>a metallic shine, are very hard and difficult to break. It often
> >>seems to occur in bark fragments first. Does any of you recognize
> >>this and does anyone have an idea what causes this or where I can
> >>find references to this phenomenon.
> >>
> >>
> >>
> >>Thanks a lot and greetings from Pauline van Rijn
> >>
> >>
> >>
> >>BIAX Consult
> >>Onderzoeksbureau voor Biologische Archeologie en Landschapsreconstructie
> >>Hogendijk 134
> >>1506 AL Zaandam
> >>tel. 075 616 10 10
> >>fax: 075 614 99 80
> >>E-mail [log in to unmask]
> >>
> >>
> >-------------------------------------
> >Naomi F. Miller
> >University of Pennsylvania Museum
> >MASCA-Museum Applied Science Center for Archaeology
> >33rd and Spruce Streets
> >Philadelphia, PA 19104
> >--------------------------------------
> >tel: (215) 898 4075; FAX: (215) 898-0657
> >www: [log in to unmask]" target="_blank">http:[log in to unmask]
>
>
> --
> Linda Scott Cummings, Ph.D.
> Paleo Research Institute
> 2675 Youngfield St.
> Golden, CO 80401
> USA
> (303) 277-9848
> fax: (303) 462-2700
> http://www.paleoresearch.com
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