Gypsum-ghost limestones facies of the Polish sulphur deposits: an analog of selenitic gypsum facies?

Andrzej Gąsiewicz

Abstract


Calcite or calcite-sulphur limestones pseudomorphic limestone after gypsum selenite crystals are a salient feature of the Polish sulphur deposits and associated (barren) carbonate rocks which serve as a cardinal argument for the bioepigenesis of the Polish stratiform sulphur deposits. Detailed investigations indicate that these postselenite rocks form distinct facies defined as gypsum-ghost facies. This facies is composed of empty or filled (mainly with calcite and sulphur) spaces ("pseudomorphs") after selenite gypsum. With regard to the main component, which is ghosts of variously developed original selenite gypsum crystals (fine, coarse selenite or sabre-like forms), they may be divided into fine gypsum-ghost subfacies and coarse gypsum-ghost subfacies. Petrographic characteristics of the gypsum-ghost limestones are inconsistent with the features of selenite gypsum deposits and clearly indicate no close analogies between these two lithologies. The differences between these facies with regard to components, matrix, porosity, structures and textures excludes them from being facies equivalents. Characteristics of these limestones suggest additional diagenetic factors which could play an important role in the preservation of original gypsum structures during the course of the alteration.


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