The experimental determination of the johannsenite-bustamite equilibrium inversion boundary

Chemical compositions of garnet and clinopyroxene and their genetic significances in Yemaquan skarn iron–copper–zinc deposit, Qimantagh, eastern Kunlun

“…The diopside, hedenbergite, and johannsenite are typical clinopyroxene in iron, copper, and lead-zinc skarn deposits, respectively and are widely utilized to study the ore-forming processes and ore exploration, especially johannsenite, which commonly develops far from intrusions (e.g., Bonev et al, 2005;Bussell et al, 1990;Canet et al, 2009;Einaudi et al, 1981;Einaudi and Burt, 1982;Mao et al, 1996;Meinert, 1982Meinert, , 1987Palinkaš et al, 2013;Zhao et al, 1983Zhao et al, , 2002 and has been studied by many researchers (Abrecht, 1980;Angel, 1984;Burt, 1977;Capitani et al, 2003;Dimanov and Sautter, 2000;Vassileva and Bonev, 2001.…”

The Role of Magmatic and Hydrothermal Fluids in the Formation of the Sasa Pb-Zn-Ag Skarn Deposit, Republic of Macedonia

“…Textural relations ( Figures 5, 8 and 9) indicate that pyroxenes were replaced by mixtures of hydrous silicates, carbonates, quartz and magnetite, reflecting an increase in water activity and oxygen and/or CO2 fugacities: * Calculated for standard conditions using thermodynamic data published by [59,60]. In contrast to the carbonate component of the host cipollino marble that was replaced by pyroxenes, grey mica has not been significantly affected by metasomatic processes during the prograde stage of the mineralization, probably due to the insufficient water activity and a relatively high K + /H + molar ratio: associated with the Sasa deposit are a product of the calc-alkaline to shoshonitic post-collisional magmatism that affected the Balkan Peninsula during the Oligocene-Miocene period [21,23,[38][39][40][41]53], resulting in the formation of numerous magmatic-hydrothermal ore deposits along the Vardar Zone and the Serbo-Macedonian Massif (Figure 1; [25][26][27][28][29][30][31][32][33][34][35]54]).…”

“…CaCO3 (calcite)+ 2 SiO2 (quartz) * Calculated for standard conditions using thermodynamic data published by [59,60].…”

“…The predomi anhydrous minerals reflects a low water activity, whereas the prevalence of pyroxene (heden over garnets (andradite) suggests a high ferrous/ferric ratio and a relatively reductive environm Absence of Fe-sulfides indicates a low sulfur fugacity during the prograde stage. Altho SEM/EDS analyses (Table 1) revealed that pyroxenes are characterized by a relatively h uniform FeO/MnO ratio, previously published data [12,58] suggest greater variations in the p composition among different ore bodies and local predomination of Mn-rich pyroxen variations may be controlled by periodical variations in the chemistry of infiltrating magmati CaCO3 (calcite) + 2 H4SiO4 + Fe 2+ ↔ CaFeSi2O6 (hedenbergite) + 3 H2O + CO2 + 2 H + CaCO3 (calcite) + 2 H4SiO4 + Mn 2+ ↔ CaMnSi2O6 (johansennite) + 3 H2O + CO2 + 2 H + and/or in local temperature oscillations: CaFeSi2O6 (hedenbergite) + Mn 2+ ↔ CaMnSi2O6 (johannsenite) + Fe 2+ rH25 °C, 1atm = −7 kJ/mole * * Calculated for standard conditions using thermodynamic data published by [59,60].…”

“…Although our SEM/EDS analyses (Table 1) revealed that pyroxenes are characterized by a relatively high and uniform FeO/MnO ratio, previously published data [12,58] suggest greater variations in the pyroxene composition among different ore bodies and local predomination of Mn-rich pyroxenes. The variations may be controlled by periodical variations in the chemistry of infiltrating magmatic fluids: * Calculated for standard conditions using thermodynamic data published by [59,60].…”