Utwory węglonośne jednostki magurskiej okolic Jordanowa i Nowego Sącza

Marian Wagner


Coal matter in the Flysch of the Magura nappe between Jordanów and Nowy Sącz

In the Eocene Flysch of the Magura Nappe there are found intercalations of coal-bearing rocks (Fig. 1, 2). They have been recorded among the Magura Sandstone (region of Naprawa — Jordanów) and in the Osielec Sandstones (region of Łabowa near Nowy Sącz) associated with Łącko Marls which form intercalations in the both above mentioned lithostratigraphic units. The following kinds of coal bearing rocks have been distinguished: coal grits, coal shales and hard-lustrous brown coal. In the Magura Sandstone the most frequent are the coal grits forming layers 1—15 cm thick (Fig. 3). Frequently they are accompanied by coal shales. The latter are built of alternating laminae of coal grits and coal. The average thickness of coal shales is 5 cm. Hard-lustrous brown coal is present in the form of lentiles 5—8 mm thick or forms coating around petrified palm stems or their fragments (Fig. 3). The brown coal is humic in character. It is almost entirely built of collinite, telinite and fusinite are its accesory components. The coal present in natural exposures is usually more or less weathered. Its chemical composition depends on the degree of weathering. The carbon content is 49,9—73,3, hydrogen 3.5—5.3 and oxygen 43.5—18 per cent by weight. The volatile components content is 35.4—58.5 per cent by weight. The least content of volatile components has been recorded in coal showing the initial stage of weathering (Table 1, Fig. 7). An attempt at explaining this phenomenon has been made (Table 1, 3, Figs. 5; 6) by constructing a model of structural unite of the examined coals with the help of statistical method of analysis of molecular structure suggested by Van Krevelen and Schuyer (1961). It seems that, a considerable decrease of volatiles matter during the initial' stage of désintégration is connected with the elimination of hydrocarbons from peripheral parts of structural units. The peripheral hydrocarbons are less stable than hydrocarbons present in the cores of units in the shape of condensed rings (Fig. 6). The coal bearing rocks dealt with are strictly connected with turbidites of Magura and Osielec Sandstones forming part of turbidite current sequences as is shown on Fig. 4.

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