Upper Miocene lignite occurrences in the Oaş Depression, Satu Mare County, Romania

Abstract

The present paper contains a significant amount of data concerning the geology, genesis and physical and chemical features of lignite in the Oaş Depression (North-western Transylvania, Romania). The present-day circular Oaş Depression is bordered by Neogene eruptive complexes; however, it is most likely that initially it functioned as a gulf of Lake Pannon. It was open to the west, north-west and most probably to the east as well. The age of the lignite-bearing unit is Late Miocene. Due to climate changes and lake level fluctuations during the Late Miocene, the sedimentary basin was occupied repeatedly by mires of forest swamp. Genetically, coal accumulated from the swampy forest vegetation which developed in certain areas. The presence of the swampy forest is proved by Glyptostrobus europaeus, Byttneriophyllum tiliifolium, and Alnus cecropiaefolia. In the Oaş Depression the lignite has excellent quality . The physical and chemical characteristics show an average caloric value of 22,100 kJ/kg.