Determination of the degree of textural orientation in recrystallized carbonate rocks
Abstract
In the phases of late diagenesis - early metamorphism the interrelated change of several parameters can be observed in the texture of carbonate rocks. One of these is the preferred orientation formed alongside the anisometric particles. In petrographic descriptions the textural orientation is determined by a qualitative approach, such as non-, low- or highly-oriented texture. Conversely several stereological methods, applicable for petrographic descriptions too, are used to determine the degree of the textural orientation.
During the examination of thin sections of limestones from the Bükkium (NE-Hungary) the author adopted the method of parallel interapps. Using this slightly complicated method the author could separate textures types of carbonate rocks having different degree of orientation. The measurements has been performed by computer-controlled image analyzing equipment (SIS V3) built and installed on an IBM AT.
The author worked out another method in order to quicken the process of measuring, using data measurement calculated directly by the applied image analyzing equipment. The degree of textural orientation was determined by applying the angular distribution of the Dmax of anisometric particles in the thin sections.
As a result, well-recrystallized textures were sorted out by the degree of preferred textural orientation, characterizing the carbonate rocks on the different stages of late diagenesis and early metamorphism.