Geol 481: Geology of Earth Resources El-Shazly, 2004 1 Magmatic Ore Deposits Mode of formation of orthomagmatic ores: 1- fractional crystallization from melt 2- liquid immiscibility between a sulfide liquid and the silicate melt. 3- liquid immiscibility between an oxide liquid and the silicate melt 4- liquid immiscibility between a carbonate liquid and the silicate melt 5- Dissemination 6- End stages of magmatic crystallization. Elements concentrated by magmatic processes: PGM, Ni, Cu, Ti, V, Cr, diamonds, minor Fe REE, Nb, Zr, Li, Be, B, U, W, Sn, and Ta. Types of orthomagmatic ores: 1- Chromite 2- Platinum Group Metals 3- Cu-Fe-Ni sulfides 4- Fe-Ti (± V) oxides 5- Diamond in kimberlites 6- REE, and Zr in carbonatites 7- Pegmatites and Greisens: Chromite Deposits Types: 1- Stratiform (Bushveld type; stable cratons) 2- Podiform (Alpine type; orogenic; associated with ophiolites, or with Archean greenstone belts). Uses of Chromite: (Cr/Fe ratio and Mg and Al contents are important; cf. Evans). 1- Source of Cr, necessary for the steel industry 2- Refractory 3- Chemical industries
Geol 481: Geology of Earth ResourcesEl-Shazly, 20041Magmatic Ore
DepositsMode of formation of orthomagmatic ores:1- fractional
crystallization from melt2- liquid immiscibility between a sulfide
liquid and the silicate melt.3- liquid immiscibility between an
oxide liquid and the silicate melt4- liquid immiscibility between a
carbonate liquid and the silicate melt5- Dissemination6- nd sta!es
of ma!matic crystallization.Elements concentrated by magmatic
processes: "#$% &i% 'u% (i% )% 'r% diamonds% minor *e +%
&b% ,r% -i% .e% .% /% 0% 1n% and (a.Types of orthomagmatic
ores:1- 'hromite2- "latinum #rou2 $etals3- 'u-*e-&i sulfides4-
*e-(i 34 )5 oxides5- Diamond in 6imberlites6- +% and ,r in
carbonatites7- "e!matites and #reisens8 Chromite DepositsTypes:1-
1tratiform 3.ush9eld ty2e: stable cratons52- "odiform 3;l2ine ty2e:
oro!enic: associated with o2hiolites% or with ;rchean !reenstone
belts5.Uses of Chromite8 3'r
