Chapter 19 Flashcards
Renewable Resources:
Replenished over short time spans meaningful to humans.
Non-renewable resources
Being formed today, but very slowly. Once extracted they will not be replenished on the human timescale.
Processes that make resources that are both renewable and non-renewable (2)
Groundwater/geothermal energy, recycling of metals
Resources
Useful materials necessary for human life and civilization.
Sub-economic/conditional resources
Resources that have been discovered but are not currently economic. (EX: low grade minerals)
Hypothetical/Speculative Resources
Resources that haven’t been discovered, but estimated to exist based on statistical analyses.
Reserves
Part of a geological resource which has been found and can be recovered economically with existing technology.
Cumulative reserves
Reserves that include the quantity of already used resources.
Metallic mineral deposits
Useful metals present in the Earth with low average concentrations and non-uniform distribution. Extraction focuses on locations where geological processes have increased the concentration.
Crustal gold concentration
0.005 g/ton (ppm)
Orogenic gold deposit concentration
10 g/ton (ppm)
Ore
Rock in which a metal occurs at a high enough concentration compared to the average composition. Such that it may be economically mined. This is not applied to non-metallic materials.
Concentration factor
(concentration of metal in ore) / (concentration of metal in average crust)
Magmatic mineral deposit
Metal concentration takes place at the same time as the formation and emplacement of magma. Can be categorized by density and immiscibility.
Cumulate deposits (3)
Heavy minerals sink to bottom of a magma body due to gravitational settling. (EX: chrome, iron, platinum)
Nickel and Copper in magmatic deposits (1)
Found in mantle melts and liquid iron sulfide. This forms concentrations of sulfide minerals (EX: pyrrhotite, with intergrown pentlandite and chalcopyrite).
Hydrothermal deposits
The accumulation of minerals in fractures and cavities resulting from the circulation of hot waters in the Earth’s crust.
Vein (lode) deposits (4)
Igneous geothermal deposits formed in fractures along which hydrothermal fluids flow, with widths that vary from cm to m. (EX: Gold, silver, copper and zinc sulfides)
Disseminated deposits (4)
Igneous geothermal deposits formed around magma bodies as fluids are expelled from cooling magma beneath a stratovolcano. Distributed within the rock volume and forms stockwork of microscopic veinlets in rocks with a porphyritic texture.
(EX: Porphyry copper deposits, molybdenum, gold and silver)
Porphyry copper deposits (3)
Formed in subduction zones as water is expelled from magma as it crystallizes.
If a volcano dies naturally, the deposit is preserved, once eroded, the deposit is exposed at the surface. (EX: Cu, Au, Mo)
Volcanogenic Massive Sulfide (VMS) Deposits (5)
Formed at black smokers at mid-ocean ridges. Metals are leached from ocean crust by hydrothermal circulation and deposited in mounds on seafloor. (EX: copper, zinc, lead, silver and gold)
Sedimentary Exhalative deposit (SEDEX) (1)
Sedimentary adjacent rift environments
(EX: Sullivan Mine, Kimberley, BC)
Hosted Stratiform Deposits:
Sedimentary adjacent ancient rift basins with sulfides in the pore space of shale.
Mississippi Valley Type (MVT) Deposit (1)
Compaction of shales releases fluids, minerals grow in cavities in limestone. (EX: Pine Point, NWT)
