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volcanic massive sulphide deposits
midocean ridge, cold, salty water penetrates faults and other cracks in the ocean floor
magmatic cooling
metals such as iron and chromium can be concentrated by gravitational settling of heavy minerals
hydrothermal process
-water warmed can be generated by the warming of ground water or seawater
-the higher the water temperature the greater amount of stuff the water can hold in solution
the slope angle
increasing the slope; increasing the driving force
blowouts
shallow depressions of dirt/dust
deflation
wind carries particles away
how much of earths surface is covered by deserts
30%
desert
an area/region, lacking moisture, often exposing expanses of barren rock and sediment and hosting climatic conditions
ore
mineral body that be mined at profit
what type of metals is lowest in weight %
silver, platinum, gold, copper, nickel, zinc
two fusible metal categories
-precious metals: metals of high intrisic value
-base metals: low intrinsic value
metal
metals of moderate hardness that can be fused with other metals to form alloys
economic factors that qualify a mineral body to be called an ore?
-concentration of the metals
-size of the orebody
-cost associated with infrastructure
-market value of metals of interest
steep slopes prone to mass wasting?
natural and man made slopes
natural slopes
-river banks
-mountain slopes
-fault surfaces
-wave-cut shorelines
-glacial valleys
man made
-road cuts
-excavation projects
-gravel pits
-quarres
-drainage ditches
types of material moved
-brittle solid material (rock)
-cohesive solid material (rocks or clay rich soils)
-loose particles (particles of soil, mud, debris of assorted sizes)
4 main types of deserts
-subtropical deserts
-polar deserts
-mid latitude deserts
-semi-arid regions
the three types of mass wasting classifications
-type of movement
-type of material moved
-rate of movement
types of movement
-falling
-sliding
-flowing
skarn characteristics
rec chalcocite crystals in marble skarn
skarns
chemical sedimentary rocks affected by contact metamorphism can host deposits called skarns
two wind depositions
loess and sand
loess
winblown silt and clay
sand
sand sized particles of resistant minerals commonly moulded by wind into dunes
mass wasting?
the downslope movement of rock or regolith driven by the source/force of gravity
vein deposits
-metal rich fluids metals penetrate larger fractures, they form mineral filled veins
-gold sometimes found in spaces between quartz crystals
know deposits
inferrred to exist, but not yet economically, legally or technologically recoverable
bauxite
readily dissolved ions are washed away from the soil, leaving a residue rich in gibbsite
abrasion
sediment particles carried in suspension can polish solid surface of exposed rock
controls of mass wasting
-properties of material involved
-slope angle
-water content of material
-removal of vegetation
-mass movement triggers
subtropical deserts
-high pressure belts between Hadley and ferell cells, dry air flows downward
banded iron does not form today because?
-oxygen in the atmosphere rusts iron on land
-most silica dissolved in the sea is used by organisms to make their skeletons
three types of circulation cells
hadley cells, polar cells and ferrell cells
polar deserts
-high pressure regions, dry air flows downward
2 physical components of a dessert
water and wind
what happens when you add water to material on a slope?
the presence of water can increase the cohesion of loose particles and adding water can destabilize the material
mass movement triggers
-vibrations
-liquefication of water
-any added stress on a material
removal of vegetation
the roots of plants anchor loose material such as soil in place on a slope
rockslide
blocks of solid, brittle rock slide down a planar surface
slump
materials move as coherent blocks along curved surfaces
non renewable sources
cannot be replenished within human lifespan
renewable resources
replenished over relatively short time spans
reserves
already identified deposits from which minerals and fuel materials can be extracted legally and economically with current technology
resource
endowment of materials useful to people and ultimately available commercially
disseminated deposits
pressure from intrusion generates lots of microscopic cracks
panning
the size of gold particles can range from dust sized or pea sized or larger
