Mineralogical and geochemical significance of secondary burial-related barite and celestine : evidence from Late Paleozoic evaporites in the Karawanke Mountains (Slovenia)

Šoster, Aleš (author), Dolenec, Matej (author), Grum Verdinek, Luna (author), Zavašnik, Janez (author)

The evaporites in the Karawanke Mountains (northwestern Slovenia) are hosted in a structurally complex lithological sequence, intercalated between Carboniferous-Permian and Permo-Triassic rocks. These evaporites are primarily composed of gypsum, with minor amounts of anhydrite, dolomite, and barite-celestine. Geochemically, the evaporites are characterized by elevated Sr (2000–2700 mg kg$^{−1}$) and low Ba (210–400 mg kg$^{−1}$) contents, reflecting the contrasting solubility behaviors of these elements in low-temperature syngenetic environments. Thermal dehydration, induced by peak burial temperatures ranging from 190 to 260 °C facilitated the transformation of gypsum to anhydrite. Subsequent cooling below the anhydrite stability threshold enabled gradual rehydration, accounting for the coexistence of both minerals. Thermal alteration also mobilized trace elements from the evaporites, which precipitated as secondary celestine and barite through dissolution-reprecipitation mechanisms, producing compositionally zoned fracture infills. The observed zoning, transitioning from Ba-rich to Sr-rich endmembers, likely reflects shifts in temperature, solubility and the chemical reactivity of evaporite-derived brine. Sulfur isotope analyses reveal δ$^{34}$S values of +11.8 to +13.7 ‰ for the evaporitic sulfates, showing minimal variation and only a small difference relative to coexisting sulfides. This small isotopic offset indicates nearly complete sulfate reduction under high-temperature conditions, consistent with thermal alteration inferred from burial temperatures. These geochemical and isotopic results put forward not only the thermal and diagenetic evolution of the Karawanke evaporites but also their broader significance as minor reservoirs of strontium, a critical element with growing industrial and technological importance.

• Language: English
• Keywords: evaporites, gypsum, barite, celestine, geochemistry, critical elements
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 12 str.
• Numbering: Vol. 85, iss. 4, art. 126354
• PID: 20.500.12556/RUL-182779
• UDC: 55
• ISSN on article: 0009-2819
• DOI: 10.1016/j.chemer.2025.126354
• COBISS.SI-ID: 258757379
• Publication date in RUL: 22.05.2026

Record is a part of a journal

• Title: Chemie der Erde
• Shortened title: Chem. Erde
• Publisher: Gustav Fischer Verlag
• ISSN: 0009-2819
• COBISS.SI-ID: 25211136

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P1-0195
• Name: Geookolje in geomateriali

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: N1-0164
• Name: Geobiokemijski cikel molibdena v kamninah in sedimentih