TY - JOUR

T1 - Changes in antimony isotopic composition as a tracer of hydrothermal fluid evolution at the Sb deposits in Pezinok (Slovakia)

AU - Kaufmann, Andreas B.

AU - Lazarov, Marina

AU - Weyer, Stefan

AU - Števko, Martin

AU - Kiefer, Stefan

AU - Majzlan, Juraj

N1 - Funding Information: Open Access funding enabled and organized by Projekt DEAL. This study was financially supported by the Deutsche Forschungsgemeinschaft (grant LA 3392/3-1 and MA 3927/32-1) which is gratefully acknowledged. M.Š. is thankful for funding from the grant APVV-22-0041.

PY - 2024/3

Y1 - 2024/3

N2 - In this work, we investigated in situ isotopic compositions of antimony (Sb) minerals from two substages of the ore deposits near Pezinok (Slovakia). The δ123Sb values of the primary Sb minerals range from −0.4 and +0.8‰ and increase progressively along the precipitation sequence. In the substage II, the early-formed gudmundite (FeSbS) shows in all sections the lowest δ123Sb values, followed by berthierite (FeSb2S4), stibnite (Sb2S3), and valentinite (Sb2O3) with the heaviest δ123Sb values. A similar trend was observed for the substage III, from the initially-formed stibnite, followed by kermesite (Sb2S2O), valentinite, senarmontite (both Sb2O3), and schafarzikite (FeSb2O4). The evolution can be rationalized by a Rayleigh fractionation model with a starting δ123Sb value in the fluid of +0.3‰, applying the same mineral-fluid fractionation factor to all minerals. Thus, the texturally observed order of mineralization is confirmed by diminishing trace element contents and heavier δ123Sb values in successively crystallized Sb minerals. Antimony in substage III was likely supplied from the oxidative dissolution of stibnite that formed earlier during substage II. The data interpretation, although limited by the lack of reliable mineral-fluid fractionation factors, implies that Sb precipitation within each substage occurred from an episodic metal precipitation, likely associated with a similar Sb isotope fractionation between fluid and all investigated Sb minerals. Large isotopic variations, induced by precipitation from a fluid as a response to temperature decrease, may be an obstacle in deciphering the metal source in hydrothermal ore deposits. However, Sb isotopes appear to be an excellent instrument to enhance our understanding on how hydrothermal systems operate.

AB - In this work, we investigated in situ isotopic compositions of antimony (Sb) minerals from two substages of the ore deposits near Pezinok (Slovakia). The δ123Sb values of the primary Sb minerals range from −0.4 and +0.8‰ and increase progressively along the precipitation sequence. In the substage II, the early-formed gudmundite (FeSbS) shows in all sections the lowest δ123Sb values, followed by berthierite (FeSb2S4), stibnite (Sb2S3), and valentinite (Sb2O3) with the heaviest δ123Sb values. A similar trend was observed for the substage III, from the initially-formed stibnite, followed by kermesite (Sb2S2O), valentinite, senarmontite (both Sb2O3), and schafarzikite (FeSb2O4). The evolution can be rationalized by a Rayleigh fractionation model with a starting δ123Sb value in the fluid of +0.3‰, applying the same mineral-fluid fractionation factor to all minerals. Thus, the texturally observed order of mineralization is confirmed by diminishing trace element contents and heavier δ123Sb values in successively crystallized Sb minerals. Antimony in substage III was likely supplied from the oxidative dissolution of stibnite that formed earlier during substage II. The data interpretation, although limited by the lack of reliable mineral-fluid fractionation factors, implies that Sb precipitation within each substage occurred from an episodic metal precipitation, likely associated with a similar Sb isotope fractionation between fluid and all investigated Sb minerals. Large isotopic variations, induced by precipitation from a fluid as a response to temperature decrease, may be an obstacle in deciphering the metal source in hydrothermal ore deposits. However, Sb isotopes appear to be an excellent instrument to enhance our understanding on how hydrothermal systems operate.

KW - Antimony isotopes

KW - Ore deposit

KW - Pezinok

KW - Precipitation sequence

KW - Rayleigh fractionation

KW - Sb sulfides and oxides

UR - http://www.scopus.com/inward/record.url?scp=85174530628&partnerID=8YFLogxK

U2 - 10.1007/s00126-023-01222-7

DO - 10.1007/s00126-023-01222-7

M3 - Article

AN - SCOPUS:85174530628

VL - 59

SP - 559

EP - 575

JO - Mineralium deposita

JF - Mineralium deposita

SN - 0026-4598

IS - 3

ER -