The Use of Museum Collection for Studying the Origin of \u201cRose-Like\u201d Calcite in the Holy Cross Mountains (South\u2013Central Poland)

Abstract

The “rose-like” calcite belongs to the most beautiful decorative carbonate rocks in the Holy Cross Mountains region in south–central Poland. This mineral occurs in the form of veins cutting Devonian limestones. The origin of the rose-like calcite was initially linked to the Variscan orogeny, but more recent studies, conducted in the 1990s of the twentieth century, documented quite a few generations of rose-like calcite mineralization and its Late Permian/Early Triassic age. It is interesting to note that the best example for studying the rose-like calcite provenance in the paleoenvironmental context is polished slabs facing six pillars in the Geological Museum of the Polish National Geological Institute - National Research Institute, Świętokrzyski Branch in Kielce. These calcite slabs come from the abandoned Mt. Zelejowa quarry located near Chęciny. Based on the calcite textural relationships and the results of stable C and O isotope determinations (changes in δ13CPDB and δ18OPDB values), the rose-like calcite from Mt. Zelejowa was postulated to be linked to the older and the younger post-Variscan (Permian/Triassic) phases. The δ18OPDB values indicated crystallization temperatures of hydrothermal fluids in the range of 21–59 °C whereas the index Z, based on clumped δ13CPDB and δ18OPDB values (≥ 120), pointed to their marine provenance. No calcite sample showed a significant influence of meteoric waters. The hydrothermal activity took place in a terrestrial environment with developed karstification (hydrothermal paleokarst), which is evidenced by the presence of red–brown internal Fe- and Mn-rich precipitates and single dripstones (stalactites). The polished rose-like calcite slabs are a unique educational example of using stable C and O isotopes for discriminating hydrothermal from meteoric karst features. It should be emphasized that these specimens are the only complete collection retained from the current Mt. Zelejowa nature reserve. Both their scientific and educational values raise visitors’ awareness of geoheritage and geodiversity protection.