LSU GEOL 1001 EXAM 2 PRACTICE QUESTIONS
AND DETAILED SOLUTIONS
◉ What is the definition of planetary differentiation?
Answer: Separation of materials based on density
◉ Because the early Earth was a large sphere of magma, the earliest
rocks that formed here were recycled into the mantle long ago. What
is the age of the oldest radiometrically dated rocks discovered on the
planet? (Or, what is the age of the oldest remaining rocks on Earth?)
Answer: 4 billion years old
◉ A research team is studying the velocity of seismic waves in
various types of rock. Using explosives, they create small explosions
to study how fast the energy waves will travel. Using the velocity
data below, infer which rocks are higher in density and which are
lower in density. Which rock or rocks have the highest density?
Rock A: 7 km/s
Rock B: 5.9 km/s
Rock C: 7.2 km/s
Rock D: 6.1 km/s
Rock E: 6.25 km/s
, Answer: Rocks A & C
◉ What is the texture of a rock?
Answer: The size, shape, and/or arrangement of minerals in a rock
◉ The geologic rock cycle presents an orderly transition from
igneous to sedimentary to metamorphic rocks. However, there are
also some alternative transitions that bypass part of the rock cycle.
Which of the following is the best example of one of those bypasses?
Answer: Sedimentary rocks are weathered into sediments, which
become lithified into sedimentary rocks
◉ If the age of a mountain range is inversely proportional to its
height, in what two regions are the youngest mountain ranges found
today?
Answer: The circum-Pacific belt and southern Europe/Asia
◉ The rock that makes up ocean basins has a density of ________ and
is made of ________.
Answer: 3.0 g/cm3; basalt
◉ A ________ is the interior of a continental mass that has been
relatively undisturbed for the last 600 million years.
Answer: craton
AND DETAILED SOLUTIONS
◉ What is the definition of planetary differentiation?
Answer: Separation of materials based on density
◉ Because the early Earth was a large sphere of magma, the earliest
rocks that formed here were recycled into the mantle long ago. What
is the age of the oldest radiometrically dated rocks discovered on the
planet? (Or, what is the age of the oldest remaining rocks on Earth?)
Answer: 4 billion years old
◉ A research team is studying the velocity of seismic waves in
various types of rock. Using explosives, they create small explosions
to study how fast the energy waves will travel. Using the velocity
data below, infer which rocks are higher in density and which are
lower in density. Which rock or rocks have the highest density?
Rock A: 7 km/s
Rock B: 5.9 km/s
Rock C: 7.2 km/s
Rock D: 6.1 km/s
Rock E: 6.25 km/s
, Answer: Rocks A & C
◉ What is the texture of a rock?
Answer: The size, shape, and/or arrangement of minerals in a rock
◉ The geologic rock cycle presents an orderly transition from
igneous to sedimentary to metamorphic rocks. However, there are
also some alternative transitions that bypass part of the rock cycle.
Which of the following is the best example of one of those bypasses?
Answer: Sedimentary rocks are weathered into sediments, which
become lithified into sedimentary rocks
◉ If the age of a mountain range is inversely proportional to its
height, in what two regions are the youngest mountain ranges found
today?
Answer: The circum-Pacific belt and southern Europe/Asia
◉ The rock that makes up ocean basins has a density of ________ and
is made of ________.
Answer: 3.0 g/cm3; basalt
◉ A ________ is the interior of a continental mass that has been
relatively undisturbed for the last 600 million years.
Answer: craton
