Page 64 - Introduction to Mineral Exploration

3: MINERAL DEPOSIT GEOLOGY AND MODELS 47

Pipe-like deposits
Cu-Ni pipes 4a
PGE pipes 4b

B. Tectonically unstable area
Intrusions same age as volcanic rocks
Rift environment
Duluth Cu-Ni-PGE 5a
Noril’sk Cu-Ni-PGE 5b
Greenstone belt in which lowermost rocks of sequence contain ultramafic rocks
Komatiitic Ni-Cu 6a
Dunitic Ni-Cu 6b
Intrusions emplaced during orogenesis
Synorogenic in volcanic terrane
Synorogenic-synvolcanic Ni-Cu 7a
Synorogenic intrusions in nonvolcanic terrane
Anorthosite-Ti 7b
Ophiolite
Podiform chromite 8a
Major podiform chromite 8b
(Lateritic Ni) (38a)
(Placer Au-PGE) (39a)
Serpentine
Limassol Forest Co-Ni 8c
Serpentine-hosted asbestos 8d
(Silica-carbonate Hg) (27c)
(Low-sulfide Au-quartz vein) (36a)
Cross-cutting intrusions (concentrically zoned)
Alaskan PGE 9
(Placer PGE-Au) (39b)

C. Alkaline intrusions in stable areas
Carbonatite 10
Alkaline complexes 11
Diamond pipes 12

Felsic intrusions

D. Mainly phanerocrystalline textures
Pegmatitic
Be-Li pegmatites 13a
Sn-Nb-Ta pegmatites 13b
Granitic intrusions
Wallrocks are calcareous
W skarn 14a
Sn skarn 14b
Replacement Sn 14c
Other wallrocks
W veins 15a
Sn veins 15b