paleonet Question from Iraq

["N. MacLeod" <N.MacLeod@xxxxxxxxx>]

This just in.

----------

A student in Iraq (Kurdish area) contacted the pbdb micropaleo group
with a question about his research - specifically he wants to know
why he was not finding microfossils in his samples.  Despite somewhat
minimal info in his answers to my questions (see below) I think he
has carbonate-marl sections and he has not found anything after
simple de-aggredation and washing with 125 mesh sieves.

Could you post this for me to paleonet and ask members there who
might be able to offer useful advice to respond directly to the
student's address (sirwanwrd@yahoo.com)?

Thanks, dave l.

Begin forwarded message:

> From: sirwan hama <sirwanwrd@yahoo.com>
> Date: 28 May 2006 09:09:30 GMT+02:00
> To: h0662bmt@cms.hu-berlin.de
> Subject: Re: answer to question on microfossils
>
>
>
> Dear Dave Lazarus
>
> thanks for replying your importance email.
>
> The presence or absence of microfossils in prepared samples depends on
> many things, including the actual presence or absence of
> microfossils in
> the samples, and also on how the samples were prepared in the
> laboratory.
> Different types of microfossil need different types of preparation
> methods. Lastly, because microfossils differ so much in size, the
> type of
> microscope used is also important. It would help us answer your
> question
> if you could first answer a couple questions from us:
> so
> 1. Are there any previous publications describing these formations?
> Could you give us full citations for these - Author, year, journal
> name,
> volume, pages, title?
> First describing by bellen 1958 (Regional geology of Iraq), so the
> type locality was by bellen in 1952 in sarmord village. after
> Charton and hart was described in 1960. so up to now no previous
> study was described.
> 2. Has anyone else found microfossils in the formations? If so, what
> precisely did they find (type of fossil) and did they explain how they
> prepared the samples?
> depend on bellen 1958 was study the type section describing that
> the only upper of 58m of the formation cantain significant flora
> and founa so the lower 400m not contain any flora and fauna. and I
> am take the sample from type locality (thickness 455m) so only
> 58-60m of the upper contain macrofossils such as Castro pods and
> brachiopods (I send you fig. when I prepared) but the lower 400m
> was no contain any fossils.
>
> 3. How did you prepare your samples in the laboratory (acids and/or
> other
> chemicals; sieving and size of sieve openings; ultrasound or other
> treatments; loose residue or mounted on slide; if mounted, what
> mounting
> medium)?
> I prepared the samples in to way after I Collect the sample depend
> on each lithologicaly facies change (rhythmic between marl and
> marly limestone):
> 1. by thin section.
> 2. cocking : I input sample in to Na2co3 with fresh water and
> coking around 30-45min after sieving by (125,100,60,50,30,20) mesh
> number type of sieving
> 4. What type of microscope are you using (transmitted or reflected
> light;
> magnification)?
> both type
>
>
>
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> rates.

David Lazarus
Museum fuer Naturkunde
Humboldt Universität zu Berlin
Invalidenstrasse 43
10115 Berlin, Germany
david.lazarus@rz.hu-berlin.de
www.museum.hu-berlin.de (path paleo/res.groups//microp)
ph: x49-30-2093-8579
fax: "  "  -8868