What is **economic geology**?
A
Study of environmental issues
B
Study of atmospheric gases
C
Study of Earth's economic resources like minerals and fuels
D
Study of plate tectonics
Analysis & Theory
Economic geology is the study of materials that can be used for economic and/or industrial purposes.
Which term refers to a **naturally occurring concentration** of a mineral that can be extracted profitably?
Analysis & Theory
An ore is a mineral or rock that can be mined for profit.
Which process is primarily responsible for the formation of **hydrothermal mineral deposits**?
A
Cooling of magma at the surface
B
Evaporation of sea water
C
Circulation of hot fluids through rocks
Analysis & Theory
Hydrothermal mineralization involves hot aqueous solutions depositing minerals in cracks and fissures.
Which of the following is a **sulfide mineral** commonly found in hydrothermal deposits?
Analysis & Theory
Galena (PbS) is a lead sulfide formed by hydrothermal processes.
Which term refers to the **removal of soluble components** from rocks during mineralization?
Analysis & Theory
Leaching is a geochemical process where minerals are dissolved and carried away by fluids.
The term **gangue** refers to:
B
Minerals with radioactive properties
C
Waste material associated with ore
D
Metamorphic rock texture
Analysis & Theory
Gangue is the worthless rock or material that surrounds or is mixed with the ore.
Which of the following minerals is formed through **magmatic segregation**?
Analysis & Theory
Chromite often crystallizes early from a magma and settles due to density differences.
Which mineral is commonly formed by **residual concentration**?
Analysis & Theory
Bauxite forms from the intense weathering of aluminum-rich rocks, leaving behind insoluble residues.
Which process forms **placer deposits**?
B
Sedimentation of volcanic ash
C
Concentration by running water
D
Magmatic differentiation
Analysis & Theory
Placer deposits are formed by mechanical concentration in river beds (e.g., gold, tin).
What is the main mineral formed in **evaporite deposits**?
Analysis & Theory
Halite (NaCl) forms in saline environments due to evaporation of sea water.
Which of the following is an **oxide ore of iron**?
Analysis & Theory
Hematite (Fe₂O₃) is an important oxide mineral of iron.
The **zone of oxidation** in ore deposits is typically found:
Analysis & Theory
The zone of oxidation forms near the surface due to exposure to oxygen and water.
Which process leads to the enrichment of ore in the **zone of secondary enrichment**?
C
Leaching and re-deposition
Analysis & Theory
Leaching removes metals from upper zones and re-deposits them at depth, enriching ores.
Which mineral is typically associated with **epithermal deposits**?
Analysis & Theory
Gold is often found in epithermal deposits associated with hot springs and shallow hydrothermal activity.
**Sulfide ore minerals** are most commonly associated with:
Analysis & Theory
Sulfide minerals like galena and chalcopyrite form in hydrothermal vein systems.
Which mineral is an important **source of copper**?
Analysis & Theory
Chalcopyrite (CuFeS₂) is the most common copper-bearing mineral.
Which type of deposit forms when **hot water flows through fractures and deposits minerals**?
Analysis & Theory
Hydrothermal veins are mineralized zones formed by fluids carrying dissolved metals.
The process of **magmatic segregation** is responsible for forming which of the following?
Analysis & Theory
Chromite and magnetite commonly form by crystallizing early from magma and settling out.
Which mineral is extracted from **placer deposits**?
Analysis & Theory
Cassiterite (tin ore) is often found in placer deposits in river beds.
Which mineral is economically extracted from **marine evaporite basins**?
Analysis & Theory
Halite is deposited from evaporating seawater and mined for salt.