Charakter tektoniki glacjalnej w iłach poznańskich kopalni węgla brunatnego „Adamów”.

Abstract

CHARACTER OF GLACIAL TECTONICS IN THE POZNAŃ CLAYS OF THE BROWN COAL MINE “ADAMOW”

Summary 

Glacitectonic disturbances have been ascertained to occur in the Tertiary Poznań clays of the brown coal mine “Adamów”. In vertical section of the formations in study the disturbances change and show certain zoning. Fvom top to bottom three zones have been distinguished:

I zone - Top series of formations. Glacitectonic disturbances are characterized by flat foldings, faults, overthrusts, fractures and squeezing of clays into the overlying Quaternary sands;

II zone - Middle series of formations. In this zone fold forms and faults disappear, strong fracturing of clays being characteristic here;

III zone - Bottom series of formations. Here are found large flat fracture planes, frequently immediately above the coal seam. This is a zone of shearing of clays from the coal seam.

Based on the field observations the author has divided the fractures into genetical types and classes of length, giving their characteristics and criteria of the division. On the basis of measurements, fracture index (Ws) has been determined as the amount of fractures in m/m². This index shows a differentiation in the vertical section of the formations considered. On the basis of the measurements of azimuths, directions of dips of fracture planes, a rose of fractures has been drawn, too. On the roses are observed directions which are more frequently found. They form two cross systems twisted to each other under an angle of 45°. The rose of fractures has been drawn according to the fractures subdivided into genetical types. They show a partial differentiation in directions of the individual types. On the basis of the analysis of fracture directions and on the observations of geological character of the formations, probable directions of transgression and stress of the glacier have been determined. The results of measurements of kinds and directions of fractures are of practical importance. Landslides observed on the slopes of the open-cut mine frequently occur along the surfaces of glacitectonical fractures. The knowledge of the directions of fractures allow us to locate the landslides and to foresee the landslide emergency.