Lithostatistical variability of beach gravels along the Polish coast of Baltic Sea

Contribution of petrographic groups along the shore collected in the middle part of the beach; the Zingg-based grain shape parameters obtained during laboratory measurements. Gravels with a dominant grain size diameter of 2–5 cm collected from the berm (or beach face) of dune and cliff sections of the Polish seacoast. The beach gravels were collected at a radius of about 50 m, along 250 m intervals of the coastline. Individual samples weighed from 2 to 5 kg and were sampled in 10 × 10 m squares. If the amount of collected material was above 2 kg, the sampling procedure was finished; if <2 kg, then the sampling area was expanded to 50 × 10 m rectangles.