ESS 101 COMPREHENSIVE EXAM
QUESTIONS AND ANSWERS WITH
VERIFIED SOLUTIONS 2026/2027
UPDATE. JUST RELEASED
1. Which seismic wave property is responsible for the creation of the P-wave shadow zone
between 104 and 140 degrees from an epicenter?
A. Reflection off the Mohorovicic discontinuity
B. Complete absorption by the liquid outer core
C. Refraction at the mantle-core boundary
D. Dispersion through the asthenosphere
Answer: C
Conceptual Explanation: P-waves are refracted (bent) as they enter the liquid outer core
due to a significant decrease in velocity, creating a shadow zone where direct waves are not
received.
2. In the context of the Wilson Cycle, which stage is characterized by the initial rifting of a
continent and the formation of a narrow, young ocean basin?
A. Suturing stage
B. Juvenile stage
,C. Terminal stage
D. Declining stage
Answer: B
Conceptual Explanation: The Juvenile stage involves the divergence of continental crust
and the creation of new oceanic crust, typically seen in modern examples like the Red Sea.
3. According to Bowen’s Reaction Series, which mineral is the last to crystallize from a cooling
silicate melt?
A. Quartz
B. Pyroxene
C. Olivine
D. Calcium-rich Plagioclase
Answer: A
Conceptual Explanation: Quartz crystallizes at the lowest temperatures at the end of the
discontinuous and continuous reaction series.
4. What is the primary driver of thermohaline circulation in the global ocean conveyor belt?
A. Density gradients caused by temperature and salinity
B. The Coriolis effect
C. Tidal forces from the moon
, D. Surface wind stress
Answer: A
Conceptual Explanation: Thermohaline circulation is driven by differences in water
density, which is controlled by temperature (thermo) and salinity (haline).
5. Which Milankovitch cycle involves the slow ‘wobble’ of Earth’s axis, completing a cycle
approximately every 26,000 years?
A. Eccentricity
B. Precession
C. Obliquity
D. Insolation
Answer: B
Conceptual Explanation: Precession refers to the change in the orientation of the Earth’s
rotational axis, affecting the timing of seasons.
6. A metamorphic rock characterized by distinct banding of light and dark minerals, formed
under high temperature and high pressure, is known as:
A. Slate
B. Gneiss
C. Schist
D. Quartzite
QUESTIONS AND ANSWERS WITH
VERIFIED SOLUTIONS 2026/2027
UPDATE. JUST RELEASED
1. Which seismic wave property is responsible for the creation of the P-wave shadow zone
between 104 and 140 degrees from an epicenter?
A. Reflection off the Mohorovicic discontinuity
B. Complete absorption by the liquid outer core
C. Refraction at the mantle-core boundary
D. Dispersion through the asthenosphere
Answer: C
Conceptual Explanation: P-waves are refracted (bent) as they enter the liquid outer core
due to a significant decrease in velocity, creating a shadow zone where direct waves are not
received.
2. In the context of the Wilson Cycle, which stage is characterized by the initial rifting of a
continent and the formation of a narrow, young ocean basin?
A. Suturing stage
B. Juvenile stage
,C. Terminal stage
D. Declining stage
Answer: B
Conceptual Explanation: The Juvenile stage involves the divergence of continental crust
and the creation of new oceanic crust, typically seen in modern examples like the Red Sea.
3. According to Bowen’s Reaction Series, which mineral is the last to crystallize from a cooling
silicate melt?
A. Quartz
B. Pyroxene
C. Olivine
D. Calcium-rich Plagioclase
Answer: A
Conceptual Explanation: Quartz crystallizes at the lowest temperatures at the end of the
discontinuous and continuous reaction series.
4. What is the primary driver of thermohaline circulation in the global ocean conveyor belt?
A. Density gradients caused by temperature and salinity
B. The Coriolis effect
C. Tidal forces from the moon
, D. Surface wind stress
Answer: A
Conceptual Explanation: Thermohaline circulation is driven by differences in water
density, which is controlled by temperature (thermo) and salinity (haline).
5. Which Milankovitch cycle involves the slow ‘wobble’ of Earth’s axis, completing a cycle
approximately every 26,000 years?
A. Eccentricity
B. Precession
C. Obliquity
D. Insolation
Answer: B
Conceptual Explanation: Precession refers to the change in the orientation of the Earth’s
rotational axis, affecting the timing of seasons.
6. A metamorphic rock characterized by distinct banding of light and dark minerals, formed
under high temperature and high pressure, is known as:
A. Slate
B. Gneiss
C. Schist
D. Quartzite
