Although the mineral deposits of the Longobucco area in the Sila Massif (Calabria, southern Italy) are historically known as metal exploitation sites since ancient times, scientific interest in their study has only recently been renewed (Fregola et al., 2023a). In particular, a detailed mineralogical characterization using modern methodologies and framed in an updated geological context, would help to decipher their genesis. We have collected samples of the mineralized bodies outcropping along a fault zone crosscutting monzodiorites at the “Torrente La Manna” site in the Longobucco area, where Vighi (1953) first observed a sphalerite-galena- pyrite-quartz-calcite mineral association. We have characterized such minerals using optical microscopy, scanning electron microscopy (SEM), electron probe microanalyses (EPMA), and micro-Raman spectroscopy. Sphalerite is the dominant polymetallic mineral, showing color and chemical zoning, and can be used as fingerprint to differentiate the evolution stages of the mineralized deposit; noteworthy its mineralogical characterization is presented in a separate contribution to this congress (Fregola et al., 2023b; session P.40). Our reconstructed paragenetic sequence comprises almost five growth stages. Early minerals include a light- colored Fe-poor sphalerite-I, followed by a darker Fe-richer sphalerite-II formed in association to euhedral quartz-I crystals. The latter show color and chemical zoning of Al, Na, K, Ca. Moreover, we have observed a Mn-rich (1.19±0.03 to 0.49±0.02 wt%) and Mg-poor (up to 0.08±0.01 wt%) calcite, partly hosting REE- fluorcarbonates. The latter minerals are reported here for the first time in the Longobucco area, and consist of synchysite, with 20 to 60 μm grain size, and total REE (Ce, La, Y, Nd, Sm, Pr, Gd, Dy) concentrations ranging between 42.64 and 2.40 wt%. Late stages minerals comprise sphalerite-III, quartz-II, pyrite, and Ag- free galena with low Sb-content (up to 0.09±0.03 wt%). Fregola, R.A., Ciccolella, A., Festa, V., Ruggieri, G., Schingaro, E., Tursi, F., & Ventruti, G. (2023a) - Review of Polymetallic Mineralization in the Sila and Serre Massifs (Calabria, Southern Italy). Minerals, 13(3), 439. https://doi.org/10.3390/min13030439 Fregola R.A., Ciccolella A., Ruggieri G., Ventruti G., Mesto E. & Schingaro E. (2023b) – Mineralogical characterization of zoned sphalerite from polymetallic mineralization of the Sila Massif (Calabria, Southern Italy): The Longobucco case study. Congresso SGI-SIMP, “The Geoscience paradigm: Resources, Risks and future perspectives”. Potenza, 19-21 sept. 2023, Abstract Book, p. . Vighi L. (1953) Sulla geologia e sulle mineralizzazioni metallifere della regione di Longobucco in Calabria. Mem. e Note Ist. Geol. Appl. Napoli, 5, 3–61.
Mineralizations of the Sila Massif (Calabria, southern Italy): The case study of the Zn-Pb ore deposit of Longobucco
Ciccolella A.;Fregola R. A.;Festa V.;Ventruti G.;Schingaro E.
2023-01-01
Abstract
Although the mineral deposits of the Longobucco area in the Sila Massif (Calabria, southern Italy) are historically known as metal exploitation sites since ancient times, scientific interest in their study has only recently been renewed (Fregola et al., 2023a). In particular, a detailed mineralogical characterization using modern methodologies and framed in an updated geological context, would help to decipher their genesis. We have collected samples of the mineralized bodies outcropping along a fault zone crosscutting monzodiorites at the “Torrente La Manna” site in the Longobucco area, where Vighi (1953) first observed a sphalerite-galena- pyrite-quartz-calcite mineral association. We have characterized such minerals using optical microscopy, scanning electron microscopy (SEM), electron probe microanalyses (EPMA), and micro-Raman spectroscopy. Sphalerite is the dominant polymetallic mineral, showing color and chemical zoning, and can be used as fingerprint to differentiate the evolution stages of the mineralized deposit; noteworthy its mineralogical characterization is presented in a separate contribution to this congress (Fregola et al., 2023b; session P.40). Our reconstructed paragenetic sequence comprises almost five growth stages. Early minerals include a light- colored Fe-poor sphalerite-I, followed by a darker Fe-richer sphalerite-II formed in association to euhedral quartz-I crystals. The latter show color and chemical zoning of Al, Na, K, Ca. Moreover, we have observed a Mn-rich (1.19±0.03 to 0.49±0.02 wt%) and Mg-poor (up to 0.08±0.01 wt%) calcite, partly hosting REE- fluorcarbonates. The latter minerals are reported here for the first time in the Longobucco area, and consist of synchysite, with 20 to 60 μm grain size, and total REE (Ce, La, Y, Nd, Sm, Pr, Gd, Dy) concentrations ranging between 42.64 and 2.40 wt%. Late stages minerals comprise sphalerite-III, quartz-II, pyrite, and Ag- free galena with low Sb-content (up to 0.09±0.03 wt%). Fregola, R.A., Ciccolella, A., Festa, V., Ruggieri, G., Schingaro, E., Tursi, F., & Ventruti, G. (2023a) - Review of Polymetallic Mineralization in the Sila and Serre Massifs (Calabria, Southern Italy). Minerals, 13(3), 439. https://doi.org/10.3390/min13030439 Fregola R.A., Ciccolella A., Ruggieri G., Ventruti G., Mesto E. & Schingaro E. (2023b) – Mineralogical characterization of zoned sphalerite from polymetallic mineralization of the Sila Massif (Calabria, Southern Italy): The Longobucco case study. Congresso SGI-SIMP, “The Geoscience paradigm: Resources, Risks and future perspectives”. Potenza, 19-21 sept. 2023, Abstract Book, p. . Vighi L. (1953) Sulla geologia e sulle mineralizzazioni metallifere della regione di Longobucco in Calabria. Mem. e Note Ist. Geol. Appl. Napoli, 5, 3–61.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
