An Integrated Approach to Characterising Sulphur Karst Springs: A Case Study of the Žvepovnik Spring in NE Slovenia

Abstract

We present an integrated approach to characterizing the Žvepovnik sulphur spring, comprising detailed basic geological (mapping), geochemical (physico-chemical, elementary), isotopic (δ2H, δ18O, δ13CDIC, δ34S and 3H), and microbiological analyses. We used a multi-parameter approach to determine the origin of the water (meteoric or deeper infiltration), the origin of the carbon and sulphur, and water retention times. Our special research interest is the origin of the sulphur, as sulphur springs are rare and insufficiently investigated. Our results show that the Žvepovnik spring occurs along the fault near the contact between the dolomite aquifer and overlying shales and volcanoclastic beds. The spring water is the result of the mixing of (1) deeper waters in contact with gypsum and anhydrite and (2) shallow waters originating from precipitation and flowing through the surface carbonate aquifer. The results of δ2H and δ18O confirm local modern precipitation as the main source of the spring. δ13CDIC originates from the degradation of organic matter and the dissolution of carbonates. We therefore propose four possible sources of sulphur: (1) the most probable is the dissolution of gypsum/anhydrite; (2) barite may be a minor source of sulphur; (3) the microbial dissimilatory sulfate reduction; and (4) the oxidation of pyrite as the least probable option.

Influence of Geological Structure on Micro-location of Submarine Karstic Sulphur Springs near Izola (SW Slovenia)

“…The described alteration of existing structural data provides a simpler but hydrogeologically consistent explanation of the spatial distribution of all spring groups. It is based on a hydrogeological conceptual model (Figure 9a -frontal view) that predicts the following: A) water springs from the limestone aquifer (core of Izola anticline) at the stratigraphic boundary between the limestone and the overlying siliciclastic succession (groundwater barrier), B) springs are located in the near-shore area, where the sedimentary cover of Quaternary deposits is thin enough to be washed out, and C) as is evident from the elevated temperatures, sulphur mineralization, and similarities with the LIV-1/01 borehole (Benedik & Rožič;Žumer, 2004Faganeli et al, 2005;Žvab Rožič et al, 2021;Šušmelj et al, 2022), groundwater originates from well buried limestone formations, below the coal-rich Liburnia Formation. We predict that the groundwater is recharged by a deep hypogenic loop from the NE (Kras Plateau) and/or SW (Istra Peninsula).…”

“…An initial dive into these depressions revealed that they are submarine springs, above which the Quaternary sediment is almost completely eroded, but the walls as well as the bottoms of these depressions are still composed of fine-clastic Quaternary deposits (Žumer, 2004, 2008). These springs show elevated temperatures (up to 29.6 °C) and sulphur content (Žumer, 2004Faganeli et al, 2005;Žvab Rožič et al, 2021;Šušmelj et al, 2022). Morphological and hydrogeological characteristics of these depressions indicate that they correspond to subaqueous pockmarks formed where focused fluids sta na južni strani, skupina Izola pa je na severni strani apnenčastega jedra Izolske antiklinale.…”

SLONIP—A Slovenian Web-Based Interactive Research Platform on Water Isotopes in Precipitation

“…The results are normalized to VSMOW/SLAP using LIMS (Laboratory Information Management System for Light Stable Isotopes) program. For details see [27,[61][62][63][64]. The overall uncertainties are estimated to be less than 1 ‰, 0.05 ‰ and 1.01 ‰ for δ 2 H, δ 18 O and deuterium excess, respectively.…”

“…The analytical details are described in [37,[40][41][42][43][44]46,54]. In 2016 the infrastructure of the JSI laboratories was improved, and since then, the isotopic composition of hydrogen (δ 2 H) and oxygen (δ 18 [27,[61][62][63][64]. The overall uncertainties are estimated to be less than 1 ‰, 0.05 ‰ and 1.01 ‰ for δ 2 H, δ 18 O and deuterium excess, respectively.…”