Abstract

Devonian deposits crop out only in the southern part of Poland—the Holy Cross Mountains (Lower, Middle and Upper), the Silesian-Crakovian plateau (Middle and Upper) and the Sudetan Mountains (parts of all stages)—but have been recognized in wells drilled in Pomerania, the Lublin plateau and the Carpathians.

All stages of the Devonian are represented in Poland and, in the Lower and Middle Devonian, are characterized by marine and continental facies. The marine deposits, which are present in the west and central areas, show continuity of sedimentation both from the Silurian to the Devonian and from the Devonian to the Carboniferous. The continental deposits are present in the southeastern part of the country.

In the Bug depression there was continuous sedimentation from Silurian to Lower Devonian. The Lower Devonian is in Old Red Sandstone facies, while the Middle and Upper Devonian are predominantly carbonate — limestone and dolomite. The total thickness exceeds 1500 m.

South of the Holy Cross Mountains, on the Silesian-Crakovian plateau and in the Carpathians, the oldest Devonian sediments are of Emsian age. They are predominantly varicoloured shales, and also of spores. The thickness reaches 200 m. The Middle and Upper Devonian are mainly limestone and dolomite with terrigenous intercalations. They carry a rich marine fauna and reach 1600 m in thickness.

In the region of Lysa Gora in the Holy Cross Mountains and in Masovia, there is continuity of sedimentation from the Silurian to the Devonian. The Gedinnian carries an abundant marine fauna. The Siegenian constitutes a passage from the marine sediments to the continental Old Red Sandstone facies, which is well developed in the Emsian, being characterized by a rich vertebrate fauna and abundant flora. The thickness of the Lower Devonian in the region of Lysa Gora and Masovia is 1000 m.

The Devonian of Poland is divisible into three lithostratigraphic series: a lower, marine and continental, clastic series; a middle carbonate, mainly dolomite series, in part shaly or sandy, with a rich fauna particularly of corals; and an upper series of calcareous clays and shales with biostromes and bioherms in the lower part.

A wide representation of nearly all marine faunal groups of the period is present and many representatives of the continental fauna and flora.