Tonsztajn ze złoża węgla kamiennego "Słupiec" w Zagłębiu Sudeckim

Wiesław Heflik, Ireneusz Lipiarski


Tonstein in the Słupiec coal deposits, Sudetes Coal Basin

A tonstein bed has been found in the colliery Nowa Ruda in the roof of the coal seam Nr 5, in the Lower Zacler Beds (Fig. la). The tonstein bed, ranging in thickness from 10 to 25 cm, is composed of three layers separated by coal intercalations (Fig. 1 b). The layers are lithologically differentiated, and the lithologic sequence present in all layers consists of: aleuritic and psefitic material at the base, followed upwards by pelitic material, and a coal layer at the top. This sequence is repeated twice in the upper layer. The tonstein is characteristically brown-coloured. Owing to the distinctive lithology and widespread occurence in the colliery, the desctibed tonstein bed is extremely useful as a marker bed. The described rock consists chiefly of kaolinite-dickite, quartz, and carbonized plant material. Flakes of altered micas, apatite and zircon form minor constituents (PI. X V and XVI). Three varieties of kaolinite and dickite were distinguished: the fine-crystalline variety was formed most probably by alteration of volcanic glass. The coarse-crystalline variety crystallized during sedimentation or during diagenesis, while the spiral variety forms pseudomorphoses after potassium feldspars, plagioclases and micas. The quartz grains display features typical for pyroclastic provenance. It is concluded that the described rock was formed of tuff material deposited and altered in peat environment.

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