exam 1 Flashcards
ore body
mass of rock from which ore might be extracted, suggests for profit
reserve
ore that may be extracted for a profit
grade
amount of given metal in a rock; usually a percentage
tonnage
volume of min. material
laterites
result of weathering, usually occur near equator
in situ ore
chemically processed in place
variables that might affect value of min. ore
extraction $$$, pureness of ore, dangerous enviro hazards, political issues, supply/demand
ore dep. variables
depth, erosion, age, formation, preservation
transporting agents:
water, melts, gas, mass flow
sources of metals:
mantle, water, magma, country rock
drives for mass transport
density, pH sediment size, topography, evaporation
magmatic ore deps SOURCES
start w/ specialized magma comps, metals originally contained in magma
what might cause a metal to come out of a solution?
dissolution, oversaturation, p/t change
magmatic ore deposit
fundamentally magmatic, metals/mins xtallize from melt
magmatic ore deps- PATHWAYS
moved in melts
magmatic ore dep traps
fractional xtallization, MM, assimilation
Hydrothermal deposits
hot fluid moving thru rock
metasomatism
can involve the intro/removal of chem components, has comp change
ligand
chem components that bond w metals and help transport
metamorphism
no compositional change
hydrotherm deposit PATHWAYS
rocks decrease in permeability/porosity w depth
hydrotherm deposit TRAP
many different traps/sinks because of precipitation
chemical sedimentary deposits
precipitate from fluid, applies to many different metals/materials
weathering/erosion related deposits
mobilization of metals during weathering/re-precipitation
sulfur solubility
whether or not S will disolve into a melt (depends on Fe)
sulfur fugacity
willingness to form minerals in a sulfidation state
sulfide stability
low temp- wide variety of fe, ni sulfides
metal partitioning - liquid immiscibility
2+ melts form
PGE
platinum group elements
magmatic ore deposit SOURCE
mafic/UM melts
magmatic ore deposit PW
M/UM melt
magmatic ore deposit TRAP
liquid imm./magma mixing/cooling
layered mafic intrusions
can be oxide or sulfide dominated, mafic, sheet like units
gangue minerals
waste rock
