Hi Jim,

do you have access to a geological institution?
For preparing thin sections, you need a few tools (simple ones but without them
it won't be easy). These tools are standard equipment for Geological
Institutions.

I couldn't find any literature (maybe someone else one the list can), so I give
you short instructions:

1) Cut a slab or cube from your sample (at least 4 or 5 mm thick so that it
doesn't break)
2) imbed it in resin (Epoxide will do if your samples are not oily or so)
3) evacuate to make sure no gas bubbles will be trapped in your sample
4) polish one side in machine (or by hand - takes time - be careful) to create
a plain surface
5) glue this plain surface unto a slide with resin (here you have to be careful
not to trap gas bubbles either, so press slab on slide and slide it off the
slide three times to avoid bubbles)
6) let it dry in oven for 24 hours or so (temperature depending on resin -
probably 50°C)
7) saw off side of slab or cube facing away from slide so it has a desirable
thickness (maybe 200 micrometers depending on sample)
8) polish in machine until it has a nice plain surface and is roughly 100
micrometers thick (this really depends on your sample)

Now you can check on the thickness under the microscope and polish off by hand
what seems too much. Keep the surface wet with water or glycerine to get a
clear, sharp image
Alternatively, to get a clear image you can
either
polish the sample on glassplates with polish powders having successively
smaller grain sizes until it has the appropriate thickness (usually 30
micrometers, but it depends on your sample) and smoothness
or
glue a cover glass on (maybe a good idea if you have found a suitable thickness
and need high magnifiction under the microscope or need to take pictures)

I hope this is of any help and doesn't sound too kryptic. Please don't hesitate
to contact me for details, questions,....
It's easiest if you find a geologist who can assist you with this. This is
standard knowledge and practice for them.

Good Luck,
Bettina




Jim Wyatt wrote:

> Hello Bettina,
>
> It is an un-described sponge from the Wolf Mountain shale of Texas. I have
> cut two specimens so far and wish to examine some of the structures in
> thin-section.
>
> Age: Pennsylvanian
> Series: Missourian/Kasimovian/ Canyon group 294-303 mybp
> Group: Graford
> Formation: Wolf Mountain Shale
>
> Locality: Pioneer Quarry / Lake Bridgeport, Wise County, Texas
>
> Associated Sponge Fauna:
> Girtyocoelia sapherica
> G. beedei
> Girtycoelia typica
> Heliospongia ramosa
> Fissispongia jacksboroensis
> F. spinosa
> Coelocladia spinosa
>
> It is from a small sample of specimens I have been working on now for
> several years. I have had some wonderful people on the list assist me in the
> past with guidance and references, such as Dorte Mehl (I have forgot her new
> married name) and Andrzej Pisera among several others. In time I will write
> up what I have found as a technical paper and seek a professional on the
> list to author it for me for publication.
>
> As an aside, I have just received a small package of 8 Cretaceous (Upper and
> Lower Santonian) sponges from Kazakhstan. Does anyone on the list know of
> any research that has been done on the paleo-porifera from the Zharyk River
> or Chilisay, Aktjubinsk region of Western Kazakhstan? One specimen is from
> the genus Guettardiscyphia, two seem to be some genus of the family
> Becksiidae, very similar superficially to Plocoscyphia with a radial
> arrangement of excurrent canals at the base with a central attachment stalk.
>
> I can load the specimens up to the internet if anyone is interested in
> seeing them.
>
> Take care,
>
> Jim Wyatt
> [log in to unmask]

___________________________________
Bettina Brodersen
GEOMAR Forschungszentrum fuer
marine Geowissenschaften
Abtlg. Palaeo-Ozeanologie
Wischhofstrasse 1-3, Geb. 4
D-24148 Kiel

Tel.: +49 (0)431 600 2822
Fax:  +49 (0)431 600 2941
email: [log in to unmask]