Coal facies studies in Denmark and Greenland

Coal of Jurassic age occurs onshore Denmark and in the Danish North Sea, whereas coal of Carboniferous and Miocene age only occurs in the Danish North Sea and onshore Denmark, respectively. The Lower-Middle Jurassic coals are the most widespread and best documented. Onshore Denmark the coals are of low rank while the Jurassic coals in the North Sea are thermally mature and hydrocarbon generating in the Søgne Basin. The Jurassic coals have a maximum thickness of ∼ 2 m and were formed in coastal plain mires and in inland fresh water mires. The Miocene brown coals, up to ∼ 2 m thick, were formed in an overall deltaic setting. Lower Carboniferous and Palaeogene coals occur in northern Greenland, Middle Jurassic coals in northeast Greenland, and Cretaceous coals in western Greenland. The Middle Jurassic low rank coals have been investigated in detail. The up to ∼ 3.5-m-thick coal seams accumulated in coastal mires and they may have an extraordinary resinite-enriched composition. Only a single Cretaceous coal seam has been investigated with regard to the depositional environment; the seam records drowning of a peat mire. The Lower Carboniferous and Palaeogene coals have not been investigated.