continuing from Christiane and Chris Prior
In general phytoliths (biogenic silica) are going to be smaller than pollen grains in any sediment. For my purposes very organic (ie, tropical rainforest) material sediments would be processed in the first instance by deflocculation to remove clay, followed by HCl (15%) and then H2O2 warm bath treatment until all or most of the reaction has finished, with intermediate distilled H2O washing, before flotation with NPT at 2.25-2.28 sg. Time consuming but it makes for clean, easier scanning of the many <15 micron phytoliths I encouter. This method has been used on samples submitted for AMS. NPT is preferred to the health hazardous Zinc bromide which gives a marginally cleaner float.
Doreen Bowdery, PhD, Visiting Fellow
School of Archaeology and Anthropology, Bdg 14
The Australian National University
Canberra ACT 0200 Australia
Phone 6125 4772
-----Original Message-----
From: The archaeobotany mailing list [mailto:[log in to unmask]] On Behalf Of Dr. Christiane Singer
Sent: Tuesday, 14 August 2007 8:46 PM
To: [log in to unmask]
Subject: pollen concentration
Dear all,
I am currently working on an organic rich clay deposit from the
Euphrates valley. AMS-dating of pollen seems to be the only way to
get any reliable age control, but as so far I did not manage to
receive sufficiently pure pollen concentrates.
The methods I have been using were: the standard methods (Faegri and
Iversen 1989) + heavy liquid separation with Sodium Polytungstate +
sieving and density solution with 1.3 sg following Vandergoes and
Prior 2003 and Newnham 2006. But still there is a lot of non-pollen
material.
Is there anybody out there who knows how to produce nice pollen
concentrates without too much other residues, or has experience with
the matter?
Best wishes
Christiane Singer
Dr. Christiane Singer
Johann Wolfgang Goethe-Universität
Institut für Archäologische Wissenschaften
-Abt. Vor- und Frühgeschichte-
D-60323 Frankfurt am Main
Tel.: +49 69 798-32112
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