Mineral Formation

Question 1

What is Hypothermal Deposition? (Igneous)

Answer 1

• Igneous intrusions form when magma cools within earths crust
—> produces superheated water that
dissolves minerals from rock

• Mineral rich solutions travel away from batholiths cooling then crystalising from most to least soluble

• This process of fractional crystallisation starts with mineral mixture that isn’t exploitable
—> after separation and deposition it
is possible

Question 2

What is Proterozoic Marine Sediment?

Answer 2

Iron deposits that formed when dissolved iron compounds became oxidised from O2 released from photosynthesis
—> Makes them soluble

• Happened 2.5-1.8 billion years ago

Question 3

What are Alluvial Deposits?

Answer 3

Materials carried and separated by flowing water

Question 4

What are Evaporites?

Answer 4

• Bay of ancient water becomes isolated
—> Evaporates, leaving crystallised
minerals

Question 5

What is secondary enrichment?

Answer 5

Economically important materials can form insoluble/soluble minerals depending on the conditions
—> may be transported in solution
and deposited as oxidation state
changes

Question 6

What is biological sedimentation?

Answer 6

When living organisms from mineral deposits

• e.g. shells of marine organisms forming limestone and chalk