Lithology-specific IRD counts of sediment core GeoB18530-1

Total and lithology-specific ice-rafted detritus (IRD) counts of sediment core GeoB18530-1 were determined by stereomicroscopically identifying, picking and counting all recognizable IRD grains from the > 1mm dry sieve fraction, which had been obtained from the 125 µm wet sieve fraction of 10 cm^3 ultrasonically dispersed sediment (10 ml syringe sample). Total IRD counts vary between 1 and 300 grains per sample, i.e. 0.1 to 3 IRD grains/cm^3. The IRD lithologies were initially sorted by their physical properties including color, hardness, cleavage, grain size, and texture. Based on these stereomicroscopic observations, we devised a new (and evolving) IRD classification scheme of rocks and rock-forming minerals that was validated and refined by SEM and thin section analysis of the largest observed IRD particles (dropstones). Digital micrographs and thin sections of each classified IRD lithology are presented in dataset (https://doi.pangaea.de/10.1594/PANGAEA.971268).