Węgiel brunatny z osadów neogenu Kotliny Orawsko-Nowotarskiej - studium petrologiczne

Ireneusz Kołcon, Marian Wagner

Abstract


Przedstawiono charakterystykę litologiczną skał węglonośnych oraz wyniki petrologicznych badań węgla brunatnego z wychodni osadów neogenu Kotliny Orawsko-Nowotarskiej. Badania wykazały, że węgiel jest interesującym obiektem przyrodniczym nie tylko ze względu na obecność rzadkiej odmiany - węgla kutykulowego - lecz przede wszystkim z uwagi na stopień uwęglenia przejściowy od węgla miękkiego do odmian matowych węgla twardego. Opis petrograficzny węgla z Orawy uściśla pojęcie granicy między tymi odmianami węgla brunatnego.

BROWN COAL FROM NEOGENE SEDIMENTS OF THE ORAWA-NOWYTARG BASIN - PETROLOGICAL STUDY

Petrological investigations of Neogene carboniferous sediments in the Orawa-Nowy Targ Basin were conducted in the zones of their natural discovers between Lipnica Mała and Chochołów (Fig. 1). The compositions of Orawa Beds, Koniówka Beds and Podczerwone Beds were recognized there. Orawa Beds (Middle Miocene) are reprezented by loams with carboniferous detritus, loamy gravels and the brown coal seam from several cm to 2.1 m thick (Figs. 2-4). Koniówka Beds (Upper Miocene or a younger part of Middle Miocene) have been formed from the loams filled with sand and carboniferous detritus and a brown coal seam (about 0.8 m thick). The lithological nature of the younger complex in Podczerwone, reckoned among Lower and Middle Miocene, is similar to Koniówka Beds. The fundamental lithotype of coal in the Orawa Basin (Tab. 2) is formed from detrital coal, panialy tranziting continuously into Iiptobioliths-delrital coal. The contents of cutinite (Tab. 3) have influence megascopic appearance of coal, so this variety of coal was distinguished in the shape of liptobioliths-detrilal coal as the mediate link between humic (detrital) coal and liptobioliths (cutinite) coal. The less frequent ingredients of coal seams being described are xylitic coal, xylitic-detrital coal and loams (Tab. 2). The gelified attrinite, tranziting continuously into densinite, is a fundamental maceral of detriral coal. Ulminite, resinite, phlobaphinite are a significant addition. The microscopic image has revealed a liptobioIiths-detrital microtexture caused by an accumulation of cutinite. This maceral has been concentrated in the thin bends which have appeared alternately with a little thicker ones which have had petrological contents typical for detrital coal (Tab. 3). Cutinile has appeared in the shape of isolated, strongly curved, one-side jagged tapes and associations with texto-ulminite in the shape of phylinite. The analysis of chemical features of coal prove that the oldest investigated part of Neogene profile in Orawa has contained coal with the features typical for dull brown coal. In the younger levels coal has had transitory features. Considering the superiority of the features connected with rank in the soft brown coal it has been included to soft brown coal (Tab. 4). Examined coal is mainly a deposit of swampy flood level grounds which have been formed in the meta-ridge of the Carpathian Foredeep.


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