Lecture 13 - Geology of commodities Copper Mineral Deposits

Question 1

Usages of Copper

Answer 1

Power generation
Building Construction
Weight of copper in average house = 200kg
Forms two alloys of bronze and brass
High electrical and heat conductivity

Question 2

Copper deposits

Answer 2

Focused on global plate boundaries
Lots of mines in Chile and USA

Question 3

Porphyry deposits

Answer 3

Porphyry copper deposits
- Most common and important
- large scale
- open pit mining
- low grade
- Forms at convergent boundaries
Stratiform sedimentary copper deposits
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Question 4

Porphyry copper deposits

Answer 4

Associated with intermediate to acidic plutonic intrusives.
Formation:
- Subduction of oceanic crust causes hydrous melt to form in mantle.
- Oxidised melts transport volatiles to upper magma chamber where fractional crystallisation and exsolution results in the ore formations.

Question 5

Porphyry rock characteristics

Answer 5

• dense network of quarts veins
• fractured host rocks

Question 6

Lowell-Guilbert model

Answer 6

Shows principle areas of sulfide mineralisation in porphyry copper deposits

Question 7

Cu deposit forms by moving Cu from large volume of magma into a much smaller volume of veined rock