An analysis of the of the chemical composition of the upper slimy precipitate layer in the Gdansk Deep demonstrated increased concentrations of Ca, Mg, K, and Na in areas associated with tectonic faults. A cluster analysis of sediment layers, with a resolution of 1 cm, revealed an alternation of layers in the pockmark with a shortening of cluster bonds between the marker elements, indicating that the groundwater enters the sedimentary strata.