Procesy diagenezy i epigenezy w skałach karbońskich północnej części podłoża monokliny przedsudeckiej na przykładzie profilu Września IG 1

Abstract

Przedstawiono wyniki badań mineralogiczno-petrograficznych skał karbońskich (namur górny, westfal A)z otworu wiertniczego Września IG 1. Określono rolę i miejsce procesów diagenezy i epigenezy w przeobrażeniach i mineralizacji badanych skał. Procesy epigenezy powiązano z działalnością płynów hydrotermalnych właściwych, których wiek określono jako waryscyjski.

PROCESSES OF DIAGENESIS AND EPIGENESIS IN CARBONIFEROUS ROCKS OF THE NORTHERN PART OF THE BEDROCK OF FORE-SUDETIC MONOCLINE ON THE EXAMPLE AT WRZESNIA IG 1 PROFILE

The paper presents the results of mineralogic and petrographic examinations of Carboniferous rocks (Upper Namurian, Westfalian A) from the Września IG 1 borehole.

The purpose of the work has been to describe a character of geologic processes which had been taking place during the development of the examined rock complex, at present, mainly built of different kinds of finegrained sandstones (dominant arkose arenites, feldspath and lithic graywackes) interlayered by siltstones and shales. Basing on the examinations' results one may assume that the decisive role for the existing shape and character of the Carboniferous beds was played by diagenesis processes while the epigenetic activity restricted itself to the close adjacent environment of hydrothermal veins. The following diagenetic processes: recrystalization of matrix, quartz blastasy, intergranular reactions, kaolinitization, sericitization, carbonatization, crystalization of autogenic carbonates and phylosilicates and increase in the stage of automorphism of some detritic mineral components, have been recognized and described.

Impact of the above processes on changes of the Carboniferous rocks has been variable (in vertical profile of the borehole). and dependent on the petrographic composition of rocks, and on the content and composition of matrix in psammite rocks.

In epigenetic veins cutting the Carboniferous rocks at high angles of 60 to 90°, presence of the following minerals has been confirmed: quartz. ankerite, siderite, adularia, albite, ankerite dolomite, dolomite. barite, calcite, gypsum and fluorite, and such ore mfnerals as: pyrite, hematite, chalcopyrite, sphalerite, marcasite, chalcocite and galena. Taking into consideration the mineral composition, structural features of the veins, their relation with the adjacent rocks and thermobarogeochemical analysis results, hydrothermal character of mineralization process has been suggested. Variscan age of the described phenomena has been assumed.