The Polish Geological Society hosted the 2nd edition of the Core Logging School (COLOS), held from 14 to 18 September 2025 in the Holy Cross Mountains, Poland. The 2nd COLOS programme was designed to further elevate the standard of sedimentological training by offering a refined blend of theoretical instruction and hands-on experience in the detailed logging of borehole cores. As archives of ancient depositional environments, climate variability, and geological processes, from fluvial dynamics to catastrophic events, cores remain indispensable to specialists across geosciences, mining, engineering geology, and environmental studies.

A total of 25 participants representing different stages of professional development took part in the workshop. The academic component of the programme was conducted at the European Centre for Geological Education in Chęciny, where attendees were introduced to advanced methods of sedimentary logging, facies analysis, and stratigraphic interpretation. The practical section of the school, held three days at the Central Core Depository in Chmielnik, allowed participants to apply these techniques directly to carefully selected successions. This edition focused on two distinct geological formations that provided an excellent basis for comparative sedimentological training:

the Miocene Machów Formation, representing a Carpathian Foredeep depositional system dominated by a large delta–fan complex, and
the Paralic Series and the Upper Silesian Sandstone Series, which comprise Upper Carboniferous coal-bearing successions of the Upper Silesian Basin, formed in coastal-marine and fluvial environments.
These contrasting settings offered participants a unique opportunity to examine a wide range of depositional features, architectural elements, and facies relationships, enriching both the analytical and interpretative aspects of the course.