Tag Archives: Petrography

First week at the Lab

Posted on by
2

Here in Vienna, things are proceeding quickly and very well. Thanks to the efficiency and the professionalism of our colleagues from the Departments of Lithospheric Research and of Geodynamics and Sedimentology and to the excellent scientific facilities available at their ‘Dünnschlif​flabor’ (thin section laboratory) in the Centre of Earth Sciences, the first set of samples is already prepared: ready for being looked at under the microscope!
http://www.airmaxfreedom.com nike air max tn

First set of thin sections.

First set of thin sections.

So, last week, coming back from London, we started also with the preparation of the second group of ceramics: 24 samples including different Nubian and Egyptian fabrics as well as imports.

At present, I’m temporary settled in the lab where I’m splitting my day between the observation of the first set of thin sections at the microscope and the preparation of the new samples together with Claudia Beybel who is patiently teaching me how to realize – step by step – a perfect ‘Dünnschliff’!

First of all, before starting with the cutting, the samples need to be consolidated, so they were immerged in a special glue (araldite) and put in vacuum so that the glue can penetrate deeply into the ceramic material. Since several of our samples (for example the Nubian wares) are very porous and brittle, this operation has sometimes to be repeated more than one time.
oakley sunglasses repair
As a next step, the samples remain 24 hours in the oven at 40 degree Celsius to become completely dry.

On the next day, they are finally ready to being cut in order to obtain a straight slice,almost completely plan.

The new cutting machine.

The new cutting machine.

Thanks to the new wonderful machine present in the lab, this procedure took relatively short time and the result was perfect.

Further steps involve the grinding and the polishing of the section; for this operation horizontal rotary plates with diamond discs of various grit sizes that magnetically adhere to the grinding wheel were used.
ray ban 3342

Polishing the section on the plate.

Polishing the section on the plate.

The plates work in water and in transition from a coarse to the next fine grit size, the surface of the sample becomes perfectly flat and smooth! The final polishing is realized by hand with Si abrasive powder.

Gluing the section on the glass.

Gluing the section on the glass.

 

 

 

 

At this point, the samples can be glued on the glass slides, previously cleaned and matte on one side. After another night in the oven at 40 degree Celsius, the samples are ready to be cut at 30 micron.

And for Claudia and me it is finally the time for a coffee together on the nice terrace of the department!

Making progress: Towards petrographic studies of our pottery samples

Posted on by
Reply

Today, Giulia is invited to watch first steps of works with our samples in the thin section laboratory of the Center for Earth Sciences, University of Vienna, Department of Lithospheric Research. We brought the first 12 samples for thin sections there yesterday – a group of Marl clay amphorae and another group of Oasis ware.

Samples1We are very grateful to all the colleagues who made this cooperation possible – the infrastructure at the Center is fabulous and promises high quality results, important steps forward for our petrographic studies on New Kingdom ceramics from Sai Island! The thin sections will allow Giulia to investigate under various types of microscopes the properties of the individual wares in detail and to assess the microstructure of the sherds. This will help us tremendously to understand the differences we have made between the wares from the macroscopic point of view and might already challenge some of our classification. For example, one “Marl D” sherd is a bit peculiar and different from the others – I suspect it might be a Mix clay after all, but hopefully the thin sections and the comparison between the samples will shed light on these questions.

We wish to thank in particular Prof. Christian Köberl, Deputy Head of the Department of Lithospheric Research (and Director General of the Natural History Museum Vienna) for his kind support, Dieter Mader for welcoming us at the department and Sigrid Hrabe and Claudia Beybel for the work in the lab, for realising the thin sections of our samples and especially for giving Giulia the great opportunity to learn a little bit about the technical steps of work.

Strengthening AcrossBorders in Vienna

Posted on by
Reply

DSC_4467Today, Giulia d’Ercole joined us at the Austrian Academy of Sciences.  As new PostDOC researcher of AcrossBorders, she will investigate in the next three years chemical, mineralogical and petrographic properties of New Kingdom ceramics from Sai. Giulia has worked at Sai Island since 2009, focused on the local ceramic tradition of the Prehistory (within the research project directed by Dr. Elena Garcea, Cassino University, Italy). She has already conducted petrographic (MI), mineralogical (X-Ray Diffraction) and chemical (X-Ray Fluor­escence) analysis on pelitic and ceramic samples from selected sites on the island. She will now expend her exper­ience of archaeometry to apply scientific analysis on samples from New Kingdom contexts on Sai.

I hope that Giulia will very soon settle down in her new domicile Vienna – “Seervaas und herzlich Willkommen!”