Showing posts with label Oligocene. Show all posts
Showing posts with label Oligocene. Show all posts

Friday, August 15, 2014

Foraminifera of Rupelian age



Dieter (Foraminifera.eu-Team) made micrographs of forams found in Rupelian (Oligocene) material from Malliss, Northern Germany
http://www.foraminifera.eu/single.php?no=1008499&aktion=suche

A field trip will lead us to this clay-pit on the 31th of August.
Details at http://ak-ozean.de/2014aug.html



Thursday, February 10, 2011

Drawings versus SEM- and optical imaging

The first foraminiferologists used drawings as the only available means of illustration. Nowadays the usage of SEM and optical imaging has become very popular. Drawings are out of fashion. The modern neglect of drawings though is questionable.
SEM and ESEM only show the surface. Internal structures seen in many transparent specimens are not visible. Soaked in oil or water even agglutinated forams show internal structures. As a result the SEM-images differ substantially from the real appearance, thus not representing, what should be shown.



Asterigerina rotula (Kaufmann, 1867), Eocene, Moravia, Czech Repbulic painted by Miroslav Bubik, Czech Geological Survey and SEM of Asterigerina guerichi Franke 1912, Eocene, Northern Germany.
While the SEM shows details, the drawing illustrates the internal structure.

Optical Images often lack quality


The optical images of Asterigerina guerichi Franke 1912, Oligocene, Kasseler Meeressande lack quality as many optical images. The smaller the size the more difficult gets the optical imaging. The main problem is caused by the thickness of the forams. The area of sharpness is very small, so that many images need to be made and stacked together. Thus optical imaging is far less used than SEM imaging.

Conclusion

Drawings should nowadays still be seen as a proper means in foram-illustration and should be used more. A combination of drawings, SEM- and optical-imaging is recommended to achieve the best result in optical representation:



Cibicides lobatulus (=Lobatula lobatula) (Walker & Jacob, 1798), recent, from sea around Smoegen, Sweden.




Cibicides lobatulus (=Lobatula lobatula) (Walker & Jacob, 1798), recent, from sea around Lizard, Cornwall, UK.




Cibicides arguta Bykova, 1954, Eocene, Moravia painted by Miroslav Bubik, Czech Geological Survey, Czech Republic

Thursday, July 1, 2010

Exhibition Foraminifera of Northern Germany


Opening:
Saturday, 7th of August 2010 at 14.00h

Ice Age Museum Lütjenburg/Germany
www.eiszeitmuseum.de

Foraminifera objects
by artist Anna Mandel
www.annamandel.de

Contact me, if you want to organize an exhibition where you are. Michael:
michael [at] foraminifera.eu

More Info



Friday, March 26, 2010

Oligocene foraminifera from Atzendorf, Germany


Prof. Mueller, Geologisch - Palaeontologische Sammlung, University of Leipzig provided a sample from Atzendorf near Stassfurt, Germany. It dates back 30 mya to the Rupelian stage, lower Oligocene. Most foraminifera are small, below 500µm in size and lived benthic. An example is Bolivina fastigia seen to the left. See the whole collection at http://www.foraminifera.eu/atzendorf.html


Some planktonics (well preserved) are found, I classify them as Globigerina globularis (see image to the right. There are several Spiroplectinellas respresenting the agglutinating foraminifera.

I am not much familiar with faunal interpretation, but would interprete from the faunal composition: 5-10% planktonics indicate open waters, which correlate with the overall smaller sized benthonics.