Dear All
I agree with Lynda Scott Cummings; I have recently had to sieve samples of VERY sticky clay which we excavated from a cave in NW England. Soaking samples in hot water (very approx 45 degree C) worked quite well, although unfortunately the clay samples contained very few seed, insect or snail remains!
best wishes
Dave Wilkinson
Dr David M Wilkinson,
Biological and Earth Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK.
E mail: [log in to unmask]
Phone: 0151 231 2245
Personal Research site: http://www.staff.livjm.ac.uk/biedwilk/
Interested in Archaeology, Fossil mammals or climate change?
http://cwis.livjm.ac.uk/bes/fossilmammal/
> -----Original Message-----
> From: The archaeobotany mailing list
> [mailto:[log in to unmask]]On Behalf Of Linda Scott Cummings
> Sent: 26 January 2005 18:41
> To: [log in to unmask]
> Subject: Re: Hydrogen peroxide for clayey samples
>
>
> Hi Group,
>
> Hydrogen peroxide is an oxidizer. That means its purpose is to
> oxidize (attack) organic remains, including the seeds and other
> organics in your sample.
>
> The first thing that we use is hot water. That disaggregates many
> clays. No risk to the samples, since the water is not boiling, but
> just hot, as you would use for washing dishes or a hot bath.
>
> If that does not work, we use dilute sodium hexametaphosphate to
> disaggregate clays and find it works quite well. Sodahex is a base
> (a strong base in concentration), and all bases have the possibility
> of attacking organics. So far, we have observed no deterioration of
> seeds in samples that we have treated with dilute sodium
> hexametaphosphate.
>
> Linda Scott Cummings
>
> >Dear colleagues,
> >
> >One of the solutions for wet sieving of clayey samples is
> the addition
> >of hydrogen peroxide, which makes the clay desintegrate. I am
> >considering using this for a set of Dutch samples, in which the
> >preservation of the seeds is of great importance. Does anyone
> >know references to studies that deal with the effects of hydrogen
> >peroxide on botanical macroremains? If possible not only concerning
> >the present or absence of particular species in a comparison of
> >treated and untreated samples, but also on the corrosion observed
> >in individual seeds? The effects could be both positive and negative,
> >as H2O2 facilitates sieving, which might cause less harm to the
> >seeds during sieving, but H2O2 may also influence the seeds by
> >corroding them...
> >
> >Many thanks in advance for your reactions,
> >
> >oTTo
> >
> >
> >
> >
> >
> >
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> >
> >
> >
> >
> >
> >***** Rijksdienst voor het Oudheidkundig Bodemonderzoek *****
>
>
> --
> 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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