MINERAL PHASES IN CARBONATE ROCKS OF THE GOGOLIN BEDS FROM THE AREA OF OPOLE SILESIA

The results of the study presented in this article made it possible to determine the types of mineral phases from which the carbonate rocks of the Gogolin Beds of Opole Silesia were built. The limestone samples were collected in the Ligota Dolna Quarry and the Gogolin Quarry. Eight samples were taken from the Gogolin Deposit - five from the Lower Gogolin Beds and three from the Upper Gogolin Beds. Eight samples were taken from the Ligota Dolna Deposit. These came from Upper Gogolin Beds. The results of the study show that the limestone of the Gogoglin Beds from the area of Opole Silesia exhibit diversified types of carbonate phases as well as non carbonate phases. In the limestone of both formations, the Lower Gogolin Beds and Upper Gogolin Beds, four types of carbonate phases were identified which present differing content of magnesium - "pure" calcite (low-magnesium calcite), Mg-calcite (magnesium calcite, also known as magnesio-calcite), dolomite, and huntite. Moreover, in the examined limestone, ankerite phase (carbonate calcium-iron phase) and siderite phase (carbonate iron phase) occurred. Carbonate phases rich in iron were also determined based on X-ray diffraction. Non-carbonate mineral phases identified in the examined rocks were mainly quartz, feldspars, clay minerals, and muscovite. These minerals were determined in the limestone of both formations: the Lower Gogolin Beds and the Upper Gogolin Beds. Potassic feldspars occurred in the limestone of the Gogolin Beds. The results of the study show that the limestone of the Lower Gogolin Beds from the area of Opole Silesia is characterized by a more diverse presence of carbonate mineral phases with differing content of magnesium than the limestone of the Upper Gogolin Beds. However, in the Lower Gogolin Beds, carbonate phases rich in iron were not determined. The limestone of the Upper Gogolin Beds presents a higher content of non-carbonate phases in comparison with the limestone of the Lower Gogolin Beds. This can be connected with the conditions of the carbonates' sedimentation. The limestone of the Lower Gogolin Beds constitutes littoral sediments poor in non-carbonate mineral phases but rich in fossils. The limestone of the Upper Gogolin Beds represents lagoonal sediments which are characterized by a low amount of organisms but a higher content of silicates and aluminosilicates.