THERMAL EFFECTS OF A BASALTIC INTRUSION ON THE SOMA LIGNITE BED IN WEST TURKEY

A mineable lignite bed (k1) in the Soma Formation from the southern pa rt of the Soma basin is of middle Miocene age and was deposited in a l acustrine environment. Its thickness reaches up to 24 m, and it is ext ensively mined by open-pit methods. The Soma Formation was invaded by an olivine basaltic intrusion during the Pliocene-Pleistocene. The int rusion has resulted in a local contact metamorphic influence at the to p level of the k1. The coal bed, on the basis of proximate analyses an d random reflectance measurement (Ro, random) of huminite/uitrinite of coals or groundmass of cokes, can be divided into normal coal, transi tion zone, and natural coke, differing in their degree of coal metamor phism. Closer to the contact point with the intrusion, moisture and vo latile matter contents rapidly decrease,while calorific value and the %Ro, random values increase.