عنوان مقاله [English]
Lavij coal deposit is situated at a distance of 48 km SW of Amol, in Central Alborz coalfield, North of Iran. Lavij coal-bearing strata in Central Alborz zone are within the Upper Triassic– Lower Jurassic formation. The coal-bearing sediments in this area are called Shemshak Formation (Upper Triassic –Lower Jurassic). This Formation consists mainly of sandstone, shale, calcareous sandstone, argillite and siltstone. Several coal seams with different thickness are interbeded with these sediments. The Shemshak Formation is underlain by the Upper Middle Triassic (thick bedded to massive dolomitic limestone) oolitic limestone (Elika Formation). It is also overlain in western section by the Upper Permian cherty limestone (Nesen Formation). The present paper deals with maceral, mineral and geochemical composition of these coals. Petrographical studies showed that the main macerals of these coals are vitrinite to semivitrinite, fusinite and exinite. The minerals of these coals are mainly clays like argillite, carbonates like calcite and sulphides like pyrite.
Seven samples were analyzed from ash of coal seam in the Lavij area. The samples were analyzed by XRF and ICP-OES for major and minor elements. The data processing showed K, Si, Al, Ti indicating presence of quartz and clay minerals, Fe, As, Mo, Se, Pb indicating presence of sulphides like pyrite, Ca and Mg indicating the presence of carbonates and Rb, Cr, Th, Ga, Ta, Nb, V indicating presence of clay minerals. The coal contained in low ash (17%) and low moisture (1.4%) and high volatile matter (32%) as compared to other coals in central Alborz.