GL101 MIDTERM EXAM QUESTIONS
AND ANSWERS
What is contact metamorphism? - Answer- Local metamorphism from heat of a nearby
magma body.
What is regional metamorphism? - Answer- Widespread metamorphism from high
pressure and temperature during mountain building.
What is an unconformity? - Answer- A gap in the geologic record caused by erosion or
non-deposition.
What principle states that younger rocks lie above older ones? - Answer- Law of
Superposition.
What is uniformitarianism? - Answer- Concept that present geologic processes operated
similarly in the past.
What is radiometric dating based on? - Answer- Decay of unstable parent isotopes into
stable daughter isotopes at a known rate.
What is the estimated age of Earth? - Answer- Approximately 4.54 billion years.
What is the theory of plate tectonics? - Answer- The idea that Earth's lithosphere is
divided into plates that move over the asthenosphere, driven by mantle convection.
What are the three main layers of Earth by composition? - Answer- Crust, Mantle, Core.
Who proposed continental drift? - Answer- Alfred Wegener in 1915.
What evidence supports continental drift? - Answer- Fit of continents, fossil matches,
rock structures, and paleoclimate indicators.
What defines a mineral? - Answer- Naturally occurring, inorganic, solid, with ordered
internal structure and definite chemical composition.
What are the most abundant elements in Earth's crust? - Answer- Oxygen, Silicon,
Aluminum, Iron, Calcium, Sodium, Potassium, Magnesium.
What are silicates made of? - Answer- SiO4 tetrahedra linked in various structures.
AND ANSWERS
What is contact metamorphism? - Answer- Local metamorphism from heat of a nearby
magma body.
What is regional metamorphism? - Answer- Widespread metamorphism from high
pressure and temperature during mountain building.
What is an unconformity? - Answer- A gap in the geologic record caused by erosion or
non-deposition.
What principle states that younger rocks lie above older ones? - Answer- Law of
Superposition.
What is uniformitarianism? - Answer- Concept that present geologic processes operated
similarly in the past.
What is radiometric dating based on? - Answer- Decay of unstable parent isotopes into
stable daughter isotopes at a known rate.
What is the estimated age of Earth? - Answer- Approximately 4.54 billion years.
What is the theory of plate tectonics? - Answer- The idea that Earth's lithosphere is
divided into plates that move over the asthenosphere, driven by mantle convection.
What are the three main layers of Earth by composition? - Answer- Crust, Mantle, Core.
Who proposed continental drift? - Answer- Alfred Wegener in 1915.
What evidence supports continental drift? - Answer- Fit of continents, fossil matches,
rock structures, and paleoclimate indicators.
What defines a mineral? - Answer- Naturally occurring, inorganic, solid, with ordered
internal structure and definite chemical composition.
What are the most abundant elements in Earth's crust? - Answer- Oxygen, Silicon,
Aluminum, Iron, Calcium, Sodium, Potassium, Magnesium.
What are silicates made of? - Answer- SiO4 tetrahedra linked in various structures.
