Tracking the origin of metasomatic and ore-forming fluids in IOCG deposits through apatite geochemistry (Nautanen North deposit, Norrbotten, Sweden)

Iron–Titanium Oxide–Apatite–Sulfide–Sulfate Microinclusions in Gabbro and Adakite from the Russian Far East Indicate Possible Magmatic Links to Iron Oxide–Apatite and Iron Oxide–Copper–Gold Deposits

“…It was proposed previously that "IOA deposits typically evolve from subduction-related water-rich and chlorine-rich intermediate magmas under a wide temperature range, almost spanning the whole igneous-hydrothermal spectrum (~1000 to 300 • C)" [19]. Several other studies of well-exposed IOA and IOCG systems also emphasize the importance of chlorine-rich fluids for scavenging and transporting ore metals during the differentiation of primary metal-rich melt and subsequent construction of the upper crustal mineralized magmatichydrothermal systems [22][23][24][25][26]30,[98][99][100]. Although the sources of these fluids vary from magmatic mantle-and crustal-derived to basinal evaporitic and meteoric [6,19,22,24], the involvement of sulfur-and chlorine-bearing fluids in the magmatic crystallization of the ITOASS-type microinclusions during development of the Ildeus arc root plutonic complex is well documented and supported by the ubiquitous presence of Cl-rich apatite and copper-silver-lead-antimony-bismuth chlorides in mafic and ultramafic rocks from the Ildeus intrusion [55,[60][61][62].…”

“…and precious (gold, silver) metals [1][2][3][4][5][6][7][8][9][10] and are commonly found in arc-related, orogenic and post-orogenic tectonic settings [1][2][3]7,[11][12][13][14][15][16][17][18][19][20]. The formation of most current models involves multi-stage magmatic-hydrothermal processes and hydrous halogen-rich fluids, which scavenge metals from primary mantle-sourced, metal-rich silicate melts [9,[21][22][23][24][25][26][27][28][29][30][31]. Evaporitic basin-derived sources were also invoked for ore-forming fluids in some IOCG-IOA systems; for example, the giant Olympic Dam Fe-REE-Cu-Au-U district in Australia, Fe-Cu-Au-mineralized systems in Central Chile and magnetite-apatite deposits along the Middle and Lower Yangtze River in China [6,[32][33][34][35][36][37][38].…”