Forming conditions of the Graikas lignite, N. Peloponnese

In Northern Péloponnèse (southern Greece) several lignite seams occur, many of which were exploited in the past decades. In the small Graikas basin, in the upland Aigialia, a 2.5-m-thick lignite seam outcrops within the Pliocene/ Pleistocene sediments. The pre-Neogene margins and the basement of the basin consist of radiolarites, pelagic limestones, and flysch of the Pindos isopic zone. The sediments filling the basin include marly, sandy and clay layers, which deposited under marine, brackish and lacustrine conditions, during the rifting of the Corinth graben (Late Pliocene-Early Pleistocene). The seam consists of lignite and clay-rich lignite layers, of matrix lithotype, with total thickness of 1.4 m, intercalating with thin marly, silty, clay and humic clay layers. Fourteen lignite samples were obtained for proximate and ultimate analyses and coal-petrography studies. The ash contents of the Graikas lignite range up to 46.2% on dry base revealing intense inorganic input. The total sulphur contents are also high up to 4%. The fixed carbon and volatile matter contents (33.2-46% and 53.9-66.8% on daf, respectively), as well as the H/C and O/C atomic ratios and the reflectance of Eu-ulminite Β (Rm 0.26-0.30%), indicate a low rank (soft brown coal, Weichbraunkohle). Micropetrographic studies revealed a Huminite content >73%, Liptinite