Grain size distribution from permafrost cores collected in 2014 on Sobo-Sise Island, Lena River Delta, Siberia

Permafrost cores were collected in the framework of the joint Russian-German Expedition LENA 2014 on Sobo-Sise Island in August 2014. Details on the sampling locations as well as the geochemical analysis of the collected samples can be found in Fuchs et al. (2017, doi:10.1594/PANGAEA.883582). In total 69 samples from four different cores were analyzed for grain size distribution. Samples were measured with a Malvern Mastersizer 3000 in a Malvern Hydro LV wet-sample dispersion unit (with deionized water as liquid). Prior to measuring, samples were treated with hydroxen peroxide (30%) three times a week and kept on a shaker for five weeks in order to remove the organic components. After this treatment, a 1% ammonia solution and 1 g of dispersing agent (Na4P2O7 × 10 H2O) were added to disperse the samples on an overhead shaker for 12 h. At least three sub-samples of each sample were measured whereof one measurement run consisted of three repeated measurements. This resulted in at least nine measurements for each sample. In the end, all the measurements for a single sample were averaged and further analyzed with GRADISTATv8 (Blott and Pye, 2001) in order to calculate the mean grain size, sorting, skewness and kurtosis according to Folk and Ward (1957). In addition, results are presented in volume percentage for the three main grain-size categories clay (< 0.002 mm particle diameter), silt (0.002 - 0.63 mm) and sand (0.63 - 2 mm).