Igneous Ores

Question 1

What is Magmatic Segregation?

Answer 1

This process takes place when the densest crystals sink to the bottom of the melt.

Question 2

What are Magmatic hydrothermal veins?

Answer 2

This is when an igneous intrusion forces into the surrounding country rock. As it intrudes , it cracks the surrounding country rock causing a series of fissures and joints. Super heated water
called brines flow directly from the intrusion. These brines and gases carry with them, in solution, ores such as Copper, Lead, Mercury and Iron. As these brines and gases cool, they solidify in the joints and cracks within the country rock to produce
mineral veins

Question 3

What are Meteoric Hydrothermal deposits?

Answer 3

Formed when groundwater is heated by the intrusion. This heating of groundwater leads to the setting up of convection as the groundwater is heated it rises. Nearer the surface it cools and descends back towards the intrusion. When near the intrusion, the groundwater becomes enriched with brines which are carried away from the intrusion due the rising groundwater. Upon cooling the metals within the groundwater cool and precipitate the metals carried either within pore spaces of joints and fissures in the country rock.

Question 4

Name a location where hydrothermal deposits are common

Answer 4

Yellowstone National Park

Question 5

What are Black smokers

Answer 5

These are formed on deep ocean floors. If there is a heat source a convection cell is created due to the ocean water percolating through the underlying rock. Due to the rising water and gases that rise to the surface being less dense than the surrounding ocean water they rise on the ocean floor to form black smoker plumes.