Data from: Dedolomitization-driven karstification and speleogenesis in central Slovenia: Mineralogical and geochemical insights

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This study examines the petrography and geochemistry of dolomite wall rock and associated dedolomite in theMravljetovo brezno v Gošarjevih rupah cave system of central Slovenia, and evaluates the influence of dedolomitizationon speleogenesis and karstification. Three distinct dedolomitization-related facies were identified: (i)Type 1, featuring dolomite replaced and cemented by calcite; (ii) Type 2, characterized by bladed and coneshapedcalcite associated with clay minerals and iron oxides; and (iii) Type 3, a detrital, stratified depositresulting from host rock weathering and allogenic sedimentation and diagenesis in phreatic conditions.Geochemical analyses reveal a progressive loss of Mg and Sr, enrichment in Ca, starting from the unaltereddolomite of the wall rocks up to all facies associated with dedolomitization. In addition, enrichment of Si, Al, Feand other silicate-associated elements was observed in all dedolomite types. Stable isotope (δ13C, δ18O) datasuggest organic carbon input and meteoric diagenesis as primary controlling factors. ΣREE+Y patterns, negativeCe anomalies (Ce/Ce* < 1) and the enrichment in some trace elements (e.g. Zr, Zn, Cu, Pb, Ba) indicate anoxidative environment with a strong detrital influence. Structural discontinuities played a crucial role indirecting fluids and detrital material along fault zones and bedding planes, which facilitated dedolomitization andsubsequently cave formation. The findings show that dedolomitization not only altered the original dolostonefabric but also facilitated speleogenesis by enhancing rock heterogeneity and increasing its susceptibility todissolution, while at the same time playing an important role in karstification and the further development ofdolostone landscape. Here, we present datasets used in the article published in the journal Sedimentary Geology (Šarc et al., 2025; https://doi.org/10.1016/j.sedgeo.2025.106986), including: Whole-rock main, minor and trace element composition of dolostone host rock and dedolomite Type 1, 2 and 3 (Šarc_et_ al_Table 1) Representative chemical composition (wt%) and atom per formula unit (apfu) for host rock matrix and drusy dolomite, as well as remnant dolomite from Type 1 dedolomite (Šarc_et_ al_Table 2) Representative chemical composition (EMPA) for particular types of calcite in dedolomitic rocks (Šarc_et_ al_Table 3) Summary of δ13C and δ18O values of dolomite and dedolomite (Šarc_et_ al_Table 4).

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