Procesy wietrzeniowe i epigenetyczne w obrębie pstrych utworów Rybnickiego Okręgu Węglowego
Abstract
WEATHERING AND EPIGENETIC PROCESSES IN MOTTLED ROCKS IN THE RYBNIK COAL MINING AREA
Summary
The processes acting within relic patches of pre-Miocene weathering cover in southern part of the Rybnik Coal Basin are characterized. In that area, weathering cover is present above top surface of the Carboniferous in over, 30% of its distribution. The studies showed the weathering of barren rocks to be accompanied in outcrop zone by fires of coal layers, leading to origin of structureless allophane and hydrohalloisite in zones of glow. Detrital quartz and illite were found to be expulsed in the course weathering degradation processes. This was accompanied by alteration of siderite into hematite and formation of gibbsite. Subsequent epigenetic processes, connected with subsidence of fossil weathering zone, resulted in origin of smectite and, thereafter, silification. The latest processes, leading to epigenetic illitization and zeolitization, were related to supply of alkali-rich solutions to Carboniferous rock massif. Distribution of products of halloisitization, smectitization and silification appears zonal and the products successively appear along with increase in distance from relic coal layers. Processes of illitization and zeolitization were superimposed on the above mentioned. That is why illite of the IInd generation (epigenetic) may be found in cement of brecciated kaolinite, halloisite as well as siliceous (quartz and ctistoballite) rocks.
Summary
The processes acting within relic patches of pre-Miocene weathering cover in southern part of the Rybnik Coal Basin are characterized. In that area, weathering cover is present above top surface of the Carboniferous in over, 30% of its distribution. The studies showed the weathering of barren rocks to be accompanied in outcrop zone by fires of coal layers, leading to origin of structureless allophane and hydrohalloisite in zones of glow. Detrital quartz and illite were found to be expulsed in the course weathering degradation processes. This was accompanied by alteration of siderite into hematite and formation of gibbsite. Subsequent epigenetic processes, connected with subsidence of fossil weathering zone, resulted in origin of smectite and, thereafter, silification. The latest processes, leading to epigenetic illitization and zeolitization, were related to supply of alkali-rich solutions to Carboniferous rock massif. Distribution of products of halloisitization, smectitization and silification appears zonal and the products successively appear along with increase in distance from relic coal layers. Processes of illitization and zeolitization were superimposed on the above mentioned. That is why illite of the IInd generation (epigenetic) may be found in cement of brecciated kaolinite, halloisite as well as siliceous (quartz and ctistoballite) rocks.