Geological structure and mineral resources

In the base of central Poland there is a wavy East European Precambrian Platform, inclined towards the west. (in the vicinity of Serock at a depth of approx. 4000 m), mainly composed of crystalline and metamorphic rocks, and adjacent to it from the west. Palaeozoic platform covered with a thick Hercynian foreground sinkhole, which is a tectonic zone of deep splits. On the Precambrian and Palaeozoic platforms there are Mesozoic deposits depicted during periods of sea transgression, tj. mainly limestones and marls. Tertiary Cenozoic formations are sea glauconite and quartzite sands, which were displaced during the subsequent Quaternary ice ages.

In the area under discussion, outside the north. the edge of the former voivodeship. Płock there were only three older glaciations: Podlasie, Krakow and Central Poland. The Baltic glaciation reached only the aforementioned end of the former voivodeship. Płock and its south. the border is similar to the north. the border of the historic Mazovia. The formations on the surface are postglacial moraine tills, sand and gravel for kem and sander. They are up to several hundred meters thick.

River valleys often have floodplain terraces, the bottom is filled with Holocene peat, river muds and dune sands. Due to the considerable thickness of the Quaternary formations, raw materials found in older rocks in the area in question are not exploited. Mainly Quaternary formations are exploited, np.: lake clays and tills as a raw material for ceramic products, river and dune sands used for the production of glass and silicate bricks, sander gravel used in the production of concrete; less often calcareous deposits under peats, which are used as fertilizer and peat.

Oligocene and mineral waters occur in the discussed area (»p. in Konstancin and Osieck) and thermal waters (Szczytno). In the past, bog iron was mined, and in the Kurpie Forest also amber. Amber appeared as the so-called. a drag torn from the bottom of the Baltic Sea by a glacier, ground and moved here along with sandwiches.