Magmatic Sulfide Ore Deposits

Abstract

Magmatic sulfide ore deposits are products of natural smelting: concentration of elements from silicate magmas (slags) by immiscible sulfide liquid (matte). Deposits occupy a spectrum from accumulated pools of matte within small igneous intrusions or lava flows, forming orebodies mined primarily for Ni and Cu, to stratiform layers of weakly disseminated sulfides, mined for platinum group elements, within large maficultramafic intrusions. One of the world's most valuable deposits, the Platreef in the Bushveld Complex in South Africa, has aspects of both of these end members. Natural matte compositions vary widely between and within deposits, controlled largely by the relative volumes of matte and slag that interact with one another.

The Jbel Saghro Au(–Ag, Cu) and Ag–Hg Metallogenetic Province: Product of a Long-Lived Ediacaran Tectono-Magmatic Evolution in the Moroccan Anti-Atlas

“…% NaCl + CaCl 2 equiv. ), while the intermediate stages related to massive tourmalinisation show temperatures of homogenization of 200-250 • C. The system then evolves toward lower salinity fluids probably belonging to the H 2 O-NaCl-CaCl 2 (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27) wt. % NaCl equiv.)…”

“…Dacite-rhyolite pyroclastic rocks (ignimbrites), along with transitional calc-alkaline I-type [15] to A-type granites, mainly characterise these SLIPs [16]. Further, LIPs are commonly related to a wide variety of metal deposits [17] including world-class deposits such as magmatic sulfide ore deposits associated with mafic and ultramafic magmatism (Ni, Cu, PGE, Cr, Ti, Fe [18,19]), with carbonatite and peralkaline complexes (Nb, Ti, REE, Zr [20,21]), or with diamondiferous kimberlites [22]. Iron oxide copper gold (IOCG) deposit types [23] and epithermal deposits of mostly low and intermediate sulfidation gold-based metal types [24][25][26] may be also related to more silicic LIPs.…”

Blade-Shaped Dikes and Nickel Sulfide Deposits: A Model for the Emplacement of Ore-Bearing Small Intrusions

“…Many of the world's major Ni-Cu-platinum group element (PGE) sulfide deposits, including those at Noril'sk (Russia), Voisey's Bay (Canada), Jinchuan and the Kalatongke-Huangshan nickel province in China, and the Midcontinent rift of the USA, are hosted by small mafic or mafic-ultramafic intrusions thought to have developed as conduits within magmatic plumbing systems (Naldrett and Lightfoot, 1999;Lightfoot and Evans-Lamswood, 2015;Barnes et al, 2016). Between them, such intrusions host the bulk of the potentially mineable sulfide Ni-Cu resources worldwide and contain some of the world's most valuable individual orebodies (Barnes et al, 2017a). Typically only a very small proportion (about 1 ppm in the case of the Noril'sk-Talnakh intrusions in the Siberian large igneous province) of the total volume of the host magmatic province is taken up by ore-bearing intrusions (Naldrett and Lightfoot, 1999).…”

The Munali Ni sulfide deposit, southern Zambia: A multi-stage, mafic-ultramafic, magmatic sulfide-magnetite-apatite-carbonate megabreccia

“…The Ni/Cu ratio at Munali of around 10 (CNM, 2016) is at the upper limit of mafic-958 ultramafic intrusion hosted deposits, with only komatiites hosting sulfides with higher Ni/Cu 959 ratios than 10 ( Barnes et al 2017). Thus, the deposit could simply be a Ni-rich, Cu-poor 960 system, or there is a significant Cu-rich sulfide body elsewhere in the system as is seen at 961 Sudbury, where Cu-rich portions are typically found at depth due to the migration of 962 fractionated Cu-rich sulfide liquid (e.g.…”