ESS 101 B Lab 5 Quiz: Sedimentary Rocks
Questions and Answers 2026/2027 Solved
100% Correct.
SECTION 1: Sedimentary Rock Classification (6 Questions)
Q1: Which of the following correctly lists the three main categories of
sedimentary rocks?
A. Clastic, chemical, and metamorphic
B. Clastic, chemical, and biochemical/organic
C. Detrital, igneous, and evaporitic
D. Siliciclastic, carbonate, and evaporite
Correct Answer: B
Rationale: Correct because sedimentary rocks are classified into three main
categories: clastic (detrital) rocks composed of transported fragments, chemical
rocks precipitated from solution, and biochemical/organic rocks formed from
biological remains.
Q2: According to the Wentworth grain size scale, sand-sized particles range from:
A. 0.0039–0.0625 mm
B. 0.0625–2 mm
C. 2–4 mm
D. 4–64 mm
Correct Answer: B
Rationale: Correct because the Wentworth scale defines sand as particles
ranging from 0.0625 mm to 2 mm in diameter, with silt being finer and gravel
being coarser.
Q3: A sandstone composed mostly of quartz with well-sorted, well-rounded
grains is classified as:
A. Arkose
B. Lithic wacke
, C. Quartz arenite
D. Graywacke
Correct Answer: C
Rationale: Correct because quartz arenite is a mature sandstone dominated by
quartz grains with high textural maturity, indicating prolonged weathering and
transport.
Q4: Which clastic sedimentary rock is characterized by angular gravel-sized
clasts (>2 mm) cemented in a finer matrix?
A. Conglomerate
B. Breccia
C. Siltstone
D. Arkose
Correct Answer: B
Rationale: Correct because breccia consists of angular gravel-sized clasts,
distinguishing it from conglomerate which contains rounded clasts, both
indicating minimal transport distance for breccia.
Q5: The difference between mudstone and shale is primarily:
A. Grain size
B. Fissility
C. Mineral composition
D. Color
Correct Answer: B
Rationale: Correct because shale is fissile, splitting easily into thin parallel layers,
whereas mudstone is massive and blocky without fissility, though both are
composed of clay-sized particles.
Q6: Which of the following best describes textural maturity in clastic sedimentary
rocks?
A. The degree of lithification and cementation
B. The extent to which a sediment approaches the ultimate end product of
weathering and transport
Questions and Answers 2026/2027 Solved
100% Correct.
SECTION 1: Sedimentary Rock Classification (6 Questions)
Q1: Which of the following correctly lists the three main categories of
sedimentary rocks?
A. Clastic, chemical, and metamorphic
B. Clastic, chemical, and biochemical/organic
C. Detrital, igneous, and evaporitic
D. Siliciclastic, carbonate, and evaporite
Correct Answer: B
Rationale: Correct because sedimentary rocks are classified into three main
categories: clastic (detrital) rocks composed of transported fragments, chemical
rocks precipitated from solution, and biochemical/organic rocks formed from
biological remains.
Q2: According to the Wentworth grain size scale, sand-sized particles range from:
A. 0.0039–0.0625 mm
B. 0.0625–2 mm
C. 2–4 mm
D. 4–64 mm
Correct Answer: B
Rationale: Correct because the Wentworth scale defines sand as particles
ranging from 0.0625 mm to 2 mm in diameter, with silt being finer and gravel
being coarser.
Q3: A sandstone composed mostly of quartz with well-sorted, well-rounded
grains is classified as:
A. Arkose
B. Lithic wacke
, C. Quartz arenite
D. Graywacke
Correct Answer: C
Rationale: Correct because quartz arenite is a mature sandstone dominated by
quartz grains with high textural maturity, indicating prolonged weathering and
transport.
Q4: Which clastic sedimentary rock is characterized by angular gravel-sized
clasts (>2 mm) cemented in a finer matrix?
A. Conglomerate
B. Breccia
C. Siltstone
D. Arkose
Correct Answer: B
Rationale: Correct because breccia consists of angular gravel-sized clasts,
distinguishing it from conglomerate which contains rounded clasts, both
indicating minimal transport distance for breccia.
Q5: The difference between mudstone and shale is primarily:
A. Grain size
B. Fissility
C. Mineral composition
D. Color
Correct Answer: B
Rationale: Correct because shale is fissile, splitting easily into thin parallel layers,
whereas mudstone is massive and blocky without fissility, though both are
composed of clay-sized particles.
Q6: Which of the following best describes textural maturity in clastic sedimentary
rocks?
A. The degree of lithification and cementation
B. The extent to which a sediment approaches the ultimate end product of
weathering and transport
