Download Ppt_Optl_Garnierite

GARNIERITE H2 (Ni,Mg) SiO4
GARNIERITE(Jules Garnier) – NAME FOR GREEN
NICKEL ORE FOUND IN POCKETS & VEINS IN
WEATHERED & SERPENTINIZED ULTRAMAFIC ROCKS;
FORMED BY LATERITIC WEATHERING OF
ULTRAMAFIC ROCKS
• GARNIERITE – MIXTURE OF Ni-Mg-HYDROSILICATES
SERPENTINE, TALC, SEPIOLITE, CHLORITE &
SMECTITE; THESE MINERALS FORMED IN
GARNIERITE IN INTIMATE MIXTURES
BLUE-GREEN BANDS
OF NICKEL ORE
• GARNIERITE COMPOSITION
1. Ni-BEARING TALC – WILLEMSEITE ( UP TO 25 WT
% Ni)
2. Ni-LIZARDITE – NEPOUITE (UP TO 34 WT% Ni)
3. NI-SEPIOLITE – FALCONDIOTE (UP TO 24 WT% NiZ)
 LATERIZATION OF ULTRAMAFIC ROCKS
• DISSOLUTION & REMOVAL OF Ni & SiO2 TO
RESIDUAL CONCENTRATION OF Ni & Fe IN
GOETHITE-RICH SURFACE LAYER(Ni LIMONITE
ORE)
• PORTION OF Ni IS LEACHED DOWNWARD IN
UNDERLYING DECOMPOSED ULTRAMAFIC ROCKS
• THIS PROCESS INCREASES Ni TOTAL
DECOMPOSED ROCKS(NICKEL SILICATES, NICKEL
SAPROLITE)
• SMALL AMOUNT OF Ni-RICH GARNIERITE
PRECIPATED IN HOLLOW SPACES
LIME GREEN GARNIERITE
GENERALIZED WEATHERING PROFILE OF
ROCK
SAPROLITE EXPOSED IN PIEDMONT, HANOVER
COUNTY. DARK MATERIAL IS WEATHERED.
NOTE HAMMER STUCK IN SAPROLITE-ROTTEN
ROCK
GOLD LATERITIC – SAPROLITIC DEPOSITS
• ELUVIAL Au PLACERS, GOLD-BEARING SAPROLITE
Au DISSEMINATED IN LATE•
RITE & SAPROLITE DEVE•
LOPED UNDER TROPICAL
•
CONDITIONS OF WEATHER•
ING OVER WIDE VARIETY OF
•
BEDROCKS