The increasing need of Critical Raw Materials (CRMs) stable supply has led many European countries to focus their attention on the metal recovery from dismissed mines, mine wastes, and landfills in the circular economy spirit. Northern Italy is characterised by more than 100 abandoned mining sites. Among them, in the Emilia Romagna Region, the Boccasuolo Ophiolite is receiving interest because the numerous disseminated dismissed historical extractive sites of Volcanogenic Massive Sulphide (VMS) deposits with a Cyprus-type metallogenic signature (Cu-Fe-Zn) [1]. These deposits occur as pods within small bodies of ophiolitic basalts cropping out as olistoliths in the Northern Apennine External Ligurian units. These ophiolites represent remnants of the Jurassic Alpine Tethys, which formed in an ocean-continent transition zone [2]. They are indeed characterised by sequences of pillow lavas associated with serpentinite and gabbro breccias, radiolarian cherts, limestones, and abundant serpentinised subcontinental mantle peridotites. Basalts show OCTZ chemical features with transitional-MORB affinity and a garnet signature (Dyn/Ybn=1.2-1.4). Boccasuolo Ophiolite’s VMS deposits were formed by circulation of metal-rich hydrothermal fluids which, mixed with heated seawater through a network of fissures, developed quartz-sulphide veins [3]. To better constrain the CRMs potential of these VMS deposits, we performed bulk rock geochemical analyses for major and trace elements, and S and C elemental content and relative stable isotopic ratio. Preliminary results reveal that basalts with mineralisation are enriched in Cu (200 times CC), Zn (118 times CC), and Ag (12 times CC) [4]. Such analyses are crucial to reconstruct the ore-formation processes and trace metal enrichment of the main rocks, which led to the formation of Cu-Fe-Znbearing sulphide deposits associated with basaltic rocks. References: [1] Garuti G. et al., (2011) Lithos 124 243-254 https://doi.org/10.1016/j.lithos.2010.11.006 [2] Kiss G. et al., (2023) Minerals 13 8 https://doi.org/10.3390/min13010008 [3] Saccani, E. (2015) Geosci. Frontiers https://doi.org/10.1016/j.gsf.2014.03.006 [4] Rudnick, R.L., Gao, S. (2014) Treatise on Geochemistry https://doi.org/10.1016/B978-0-08-095975- 7.0.00301-6
Revived interest in dismissed historical Cu-Fe-Zn deposits in the Northern Apennine ophiolites (Italy)
Tagliacollo L.
Primo
;Bonadiman C.Secondo
;Saccani E.;Bianchini G.;Brombin V.;Tassinari R.Ultimo
2024
Abstract
The increasing need of Critical Raw Materials (CRMs) stable supply has led many European countries to focus their attention on the metal recovery from dismissed mines, mine wastes, and landfills in the circular economy spirit. Northern Italy is characterised by more than 100 abandoned mining sites. Among them, in the Emilia Romagna Region, the Boccasuolo Ophiolite is receiving interest because the numerous disseminated dismissed historical extractive sites of Volcanogenic Massive Sulphide (VMS) deposits with a Cyprus-type metallogenic signature (Cu-Fe-Zn) [1]. These deposits occur as pods within small bodies of ophiolitic basalts cropping out as olistoliths in the Northern Apennine External Ligurian units. These ophiolites represent remnants of the Jurassic Alpine Tethys, which formed in an ocean-continent transition zone [2]. They are indeed characterised by sequences of pillow lavas associated with serpentinite and gabbro breccias, radiolarian cherts, limestones, and abundant serpentinised subcontinental mantle peridotites. Basalts show OCTZ chemical features with transitional-MORB affinity and a garnet signature (Dyn/Ybn=1.2-1.4). Boccasuolo Ophiolite’s VMS deposits were formed by circulation of metal-rich hydrothermal fluids which, mixed with heated seawater through a network of fissures, developed quartz-sulphide veins [3]. To better constrain the CRMs potential of these VMS deposits, we performed bulk rock geochemical analyses for major and trace elements, and S and C elemental content and relative stable isotopic ratio. Preliminary results reveal that basalts with mineralisation are enriched in Cu (200 times CC), Zn (118 times CC), and Ag (12 times CC) [4]. Such analyses are crucial to reconstruct the ore-formation processes and trace metal enrichment of the main rocks, which led to the formation of Cu-Fe-Znbearing sulphide deposits associated with basaltic rocks. References: [1] Garuti G. et al., (2011) Lithos 124 243-254 https://doi.org/10.1016/j.lithos.2010.11.006 [2] Kiss G. et al., (2023) Minerals 13 8 https://doi.org/10.3390/min13010008 [3] Saccani, E. (2015) Geosci. Frontiers https://doi.org/10.1016/j.gsf.2014.03.006 [4] Rudnick, R.L., Gao, S. (2014) Treatise on Geochemistry https://doi.org/10.1016/B978-0-08-095975- 7.0.00301-6I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
