Download economy minerals

Process
Magmatic processes
1) segregation by settling
2) fractional crystallization
Mineral deposit
1) chromite deposits in layered
intrusions
2) pegmatites
mineral/energy resource
1) chromium, vanadium, nickel, copper,
cobalt, platinum
2) beryllium, lithium, tantalum
Sedimentary processes
1) precipitation (chemical)
2) precipitation (organic)
3) flowing water
4) wind
1) evaporites. oolites, iron
deposits
2) phosphorites, hydrocarbon,
limestone
3a) placer
3b) stream deposits
4a) dune
4b) loess
1) halite, sylvite, borax, gypsum, trona, BIF
2) phosphate, oil, coal, limestone
3a) gold, platinum diamonds, tin, ilmenite,
rutile, zircons
3b) sand and gravel
4a) sand 4b) soil
Weathering / Ground water
residual soils
residual weathering deposits
groundwater deposits
brines
geothermal wells
water
clay
nickel, iron, cobalt, aluminum, gold
travertine, uranium, sulfur
lead, zinc, copper
hot water, electricity
drinking water, irrigation
Metamorphic processes
contact metaqmorphism
regional metamorphism
tungsten, copper, tin, lead, zinc, gold, silver
gold, tungsten, copper, talc, asbestos
Hydrothermal processes
(e.g. black smokers)
hydrothermal deposits
copper, lead, zinc, molybdenum, tin, gold,
sliver
Plate Tectonics and Mineralization
• Structural features of the Earth
• Major plates & Plate boundaries
• Plate tectonic cycle
• Mineralization
Lithosphere
vs
Asthenosphere
Conservative
(Transform)
Divergent
Convergent
3 Types of Plate Boundaries
Divergent
Boundaries
Conservative
Convergent
Boundaries
Transform Boundaries
Plate Motion
Hot spot and origin of
island chains
Intra-plate Volcanism
(Hot Spots)
Continental Drift & Sea-floor Spreading
Plate Tectonics’ Cycle
Plate Tectonics and Rock Cycle
Mineralization and Divergent Boundary
(Mid-oceanic ridge)
Submarine hydrothermal vent or “Black Smoker”
Cyprus type: associated with tholeiitic basalts in ophiolite sequences copper
rich withgold. e.g. Troodos Massif (Cyprus). Besshi-type: associated with
volcanics and continental turbidites, copper/zinc with gold and silver.e.g.
Sanbagwa (Japan). Kuroko-type: associated with felsic volcanics particularly
rhyolite domes copper/zinc/lead with gold and silver, e.g. Kuroko deposits
Ophiolites are pieces of oceanic plate that have been thrusted
(obducted) onto the edge of continental plates. They provide
m o d e l s f o r p r o c e s s e s a t m i d - o c e a n r i d g e s.
Ophiolites are
thought to represent
slices of oceanic crust
that have been thrust
or obducted onto a
continental margin
during collision. They
are characterised by
a sequence of rock
types, consisting of
deep sea sediments
overlying basaltic
pillow lavas, sheeted
dykes, gabbros and
p e r i d o t i t e s.
Pillow Basalts
Ophiolite Complex
Sheeted dikes
(Diabase)
Gabbros
Peridotites
Podiform chromite deposits are irregular but fundamentally
lenticular chromite-rich bodies that occur within Alpine
peridotite or ophiolite complexes. Thus, they generally occur
in orogenic settings.
Chromite:
FeCr2O4
Podiform
chromite
deposit,
Cyprus
Mineralization at Convergent Boundaries
Geological Processes
Calcalkaline Magma Series
Volcano-plutonic complexes
Subaerial / Submarine volcanism
Porhyry / Massive sulphide deposits
Plutonism: Granitic batholiths / Stocks
Pegmatitic/ Hydrothermal / Skarn / Greisen/ deposits
Regional Metamorphism (High P/ Low T and Low P/High T )
Some gemstone deposits e.g. jade and corundum
The ASARCO Mission Mine near Tucson, Arizona
Detailed Cross - Section of a Porphyry Copper Deposit
Intraplate Mineralization
Lopolith
Sill
Bushveld stratiform chromite deposit
Schematic model of a fully grown kimberlite pipe
MASTER LIST OF ALL DEPOSIT GROUPS
A - Organic
B - Residual/Surficial
C - Placer
D - Continental Sediments and
Vocanics
E - Sediment-Hosted
F - Chemical Sediment
G - Marine Volcanic Association
H - Epithermal
I - Vein, Breccia and Stockwork
J - Manto
K - Skarn
L - Porphyry
M - Ultramafic / Mafic
N - Carbonatites
O - Pegmatite
P - Metamorphic-hosted
Q - Gems and Semi-precious Stones
R - Industrial Rocks
S - Other
Genetic Classifications of Mineral Deposits
• Syngenetic deposits
layered mafic intrusion type deposits
volcanogenic massive sulphide deposits
sedimentary massive sulphide deposits
placer deposits
• Epigenetic
porphyry deposits
skarn deposits
pegmatitic deposits
hydrothermal deposits
Classifications Based on Geological Processes
Hydrothermal/Pegmatitic mineral deposits form in association with hot water- or gas-rich
fluids
Magmatic mineral deposits concentrated in igneous rocks;
Metamoprhogenic mineral deposits concentrated by metamorhism / metasomatism
Sedimentary mineral deposits are precipitated from a solution, typically sea water;
Placer minerals are sorted and distributed by flow of water (or ice);
Residual mineral deposits formed by weathering reactions at the earth's
Classifications Based on Host Lithology
• Unconsolidated Deposits
• Sedimentary Rocks
• Volcanic Rocks
• Intrusive Rocks
• Regionally Metamorphosed Rocks