The traces of the oldest glaciations in mountainous regions are often difficult to identify. Repeated glacier advances can destroy or cover earlier landforms, meaning that conventional geomorphological evidence may no longer be preserved in the landscape. However, new insights can be gained by analyzing individual sand grains.
In our recent paper published in Geology, we present the first direct evidence of Chibanian (Middle Pleistocene) glaciation in the Western Carpathians. The study was conducted in the Demänová Cave System in the Low Tatras, Slovakia. Using scanning electron microscopy, we analyzed the surface microtextures of quartz grains. Their characteristic microfeatures can reveal grains that were transported and modified by glacial activity.
Of particular importance were grains preserved in dated clastic cave sediments. Their presence indicates that glacier activity occurred before 350,000 years ago, i.e. prior to MIS 10. In addition, some well-rounded quartz grains derived from Triassic rocks may indicate glacial activity during MIS 6.
The method is particularly useful in karst areas, where younger sediments may contain material reworked from older moraines. Analyzing grain microtextures can therefore help identify traces of glaciations whose geomorphological record has subsequently been erased.
The first author of the paper is Dawid Siemek, MSc – a graduate of our Faculty and currently a PhD student at Jagiellonian University. His PhD supervisor and co-author of the paper is Jacek Szczygieł, PhD, DSc, Associate Professor at the University of Silesia, from our Institute of Earth Sciences. The paper was also featured on the cover of Geology.
Open-access publications can be read here: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G54825.1/733716/Middle-Pleistocene-gt-350-ka-glaciation-in-the