Evolution of a hydrothermal ore-forming system recorded by sulfide mineral chemistry: a case study from the Plaka Pb–Zn–Ag Deposit, Lavrion, Greece

Abstract

Laser ablation-inductively coupled plasma-mass spectrometry and electron-probe microanalysis were used to investigate the trace-element contents of sphalerite, chalcopyrite and pyrite from the Plaka Pb–Zn–Ag deposit. Using petrographic observations, the analytical results could be linked to the temporal evolution of the Plaka ore-forming system. Sphalerite chemistry reliably records the temperature and fS2 evolution of the system, with estimated formation temperatures reproducing the microthermometric results from previous fluid-inclusion studies. Chalcopyrite chemistry also shows systematic variations over time, particularly for Cd, Co, Ge, In, Sn and Zn concentrations. Measurable pyrite was only found in association with early high-temperature mineralisation, and no clear trends could therefore be identified. We note, however, that As and Se contents in pyrite are consistent with formation temperatures estimated from co-existing sphalerite. Statistical analysis of the sphalerite data allowed us to identify the dominant geological controls on its trace-element content. The three investigated factors temperature, fS2, and sample location account for > 80% of the observed variance in Mn, Fe, Co, Ga, Ge, In, Sb and Hg concentrations, and > 60% of the observed variance in Cd and Sn concentrations. Only for Cu and Ag concentrations is the explained variance < 50%. A similarly detailed analysis was not possible for chalcopyrite and pyrite. Nevertheless, comparison of the results for all three investigated minerals indicates that there are some systematic variations across the deposit which may be explained by local differences in fluid composition.

Trace-element distribution and ore-forming processes in Au–Ag-rich hydrothermal chimneys and mounds in the TA25 West vent field of the Tonga Arc

“…9h and ESM 2 Table S4). This is consistent with previous studies that showed the direct substitution of Hg 2+ for Zn 2+ is facilitated in Fe-poor sphalerite that is in turn associated with relatively low-temperature fluid conditions (Grammatikopoulos et al 2006;Keith et al 2014;Frenzel et al 2022). However, this contrasts with sphalerite from the sulfide-rich chimneys that have decreased Hg concentrations from stage I to stage II (Fig.…”

Trace elements of sulfides in the Dengjiashan Pb–Zn deposit from West Qinling, China: Implications for mineralization conditions and genesis

“…Note: GGIMF is a temperature calculation method cited from Frenzel et al, 2016Frenzel et al, , 2022 content of In in sphalerite from the Dengjiashan deposit was 0.3 ppm, which is similar to that of a SEDEX-type Pb-Zn deposit, considering the geological as well as the aforementioned characteristics of this deposit type.…”

“…According to the characteristic elements in single minerals or mineral pairs in the coexisting phase, the content, ratio and distribution coefficient of the trace elements are calculated and determined in order to obtain the geological thermometer (Liu et al, 1984;Zheng, 1986). The composition of trace elements in sphalerite is closely linked to its formation temperature (Frenzel et al, 2016(Frenzel et al, , 2022Möller, 1987). Under hightemperature conditions, the activity (vibration) range of atoms is relatively high, and the four-coordinated ionic radii of Fe 2+ (0.63 Å), Mn 2+ (0.66 Å), In 3+ (0.62 Å), and Zn 2+ (0.60 Å) are close to each other.…”

“…This indicates that the sphalerite of the Dengjiashan deposit may have been formed at a medium mineralization temperature (Table 2). Frenzel et al (2016Frenzel et al ( , 2022 systematically summarized and compared the trace element composition of sphalerite in different types of Pb-Zn deposits while also measuring the fluid homogenization temperature. Combined with the first principal component analysis, a sphalerite Ga, Ge, Fe, Mn and In trace element thermometer was established.…”

“…Certain elements pose constraints on studying the physicochemical conditions of ore-forming fluids (Barton & Skinner, 1979;Craig & Scott, 1974;Fernández et al, 2000;Helgeson, 1969). They not only provide reliable ore-forming temperature data (Frenzel et al, 2016(Frenzel et al, , 2022Möller, 1987;Oftedal, 1941;Warren & Thompson, 1945), but also indicate the genesis of deposits and can be used to distinguish between different deposit types (di Benedetto et al, 2005;Hu et al, 2019;Wei et al, 2021;Ye et al, 2016;Zhang, 1987). In the relatively recent past, due to the limitations of analytical testing instruments, data could only be obtained through single mineral selection tests, which did not allow for the guarantee of a sample's purity with sufficient confidence.…”