Karlsbader Sprudelstein

by Bernardo Cesare, Department of Geosciences, University of Padova, Padova, Italy

Technological Progress in optical microscopy includes the automated acquisition of hi-resolution digital version of geological samples under polarized light. The huge quantity of data stored in these files allows, among other things, to zoom continuously from the entire thin section – up to 5 cm wide – down to micrometric features such as grain boundaries or mineral inclusions. This novel mode of observation opens unprecedented avenues both in research and teaching.
This animation provides a short and incomplete idea of this novel viewing option. It shows the general view of an unusual sedimentary rock - “Karlsbader Sprudelstein” from the Czech Republic - made of coated grains (“ooids”) of the carbonate aragonite. Zooming in, one can appreciate the fine structure of the cement crystals coating all grains and filling the porosity among grains, as well as the details of the aragonite coatings, whose thickness can be <10 µm.

Composite of 1482 tile images obtained in 6 crossed linear polarization channels with a Zeiss Axioscan Z1mounting a N-Achroplan 10x 0.25 Pol objective and an Axiocam 705m camera. Tiles were stitched online, a merged image of all 6 polarization angles is shown. Circular polarization mode.

Maximum width of view c. 1 cm.

Sample kindly provided by Axel Munnecke.
Further info at https://imaggeo.egu.eu/view/12282/