ESS 101 B LAB 2: SEDIMENTARY ROCKS
ADVANCED QUESTIONS AND ANSWERS
2026/2027 UPDATE || 100% GUARANTEED
PASS
1. Which transport medium typically results in the best sorting and rounding of sediment
grains due to high energy and consistent direction?
A. Glacial ice
B. Debris flows
C. Wind (Eolian)
D. Flash floods
Answer: C
Conceptual Explanation: Wind is highly selective and provides constant abrasion, leading
to well-sorted and well-rounded grains compared to the chaotic nature of ice or debris
flows.
2. A sedimentary rock consists of poorly sorted, angular quartz, K-feldspar, and rock
fragments. Which depositional environment is most likely?
A. Deep marine trench
B. Abyssal plain
,C. Barrier island
D. Alluvial fan
Answer: D
Conceptual Explanation: Alluvial fans are proximal to the source, resulting in immature
sediments with angular grains and unstable minerals like feldspar (Arkose).
3. What distinguishes a Breccia from a Conglomerate?
A. Mineral composition
B. Clast roundness
C. Degree of sorting
D. Grain size
Answer: B
Conceptual Explanation: Breccias have angular clasts indicating minimal transport, while
conglomerates have rounded clasts indicating significant transport.
4. Which of the following minerals is most resistant to chemical weathering and therefore
most common in mature detrital sedimentary rocks?
A. Olivine
B. Calcium-plagioclase
C. Pyroxene
, D. Quartz
Answer: D
Conceptual Explanation: Quartz is chemically stable at Earth’s surface conditions and
lacks cleavage, making it highly resistant to both chemical and physical weathering.
5. The process of ‘fissility’ is most commonly associated with which sedimentary rock?
A. Shale
B. Siltstone
C. Sandstone
D. Micrite
Answer: A
Conceptual Explanation: Fissility refers to the ability of a rock to split into thin layers, a
characteristic property of shale due to the alignment of clay minerals.
6. In a marine transgression, which vertical sequence of facies would you expect to see from
bottom to top?
A. Limestone, Shale, Sandstone
B. Shale, Sandstone, Limestone
C. Sandstone, Shale, Limestone
D. Limestone, Sandstone, Shale
ADVANCED QUESTIONS AND ANSWERS
2026/2027 UPDATE || 100% GUARANTEED
PASS
1. Which transport medium typically results in the best sorting and rounding of sediment
grains due to high energy and consistent direction?
A. Glacial ice
B. Debris flows
C. Wind (Eolian)
D. Flash floods
Answer: C
Conceptual Explanation: Wind is highly selective and provides constant abrasion, leading
to well-sorted and well-rounded grains compared to the chaotic nature of ice or debris
flows.
2. A sedimentary rock consists of poorly sorted, angular quartz, K-feldspar, and rock
fragments. Which depositional environment is most likely?
A. Deep marine trench
B. Abyssal plain
,C. Barrier island
D. Alluvial fan
Answer: D
Conceptual Explanation: Alluvial fans are proximal to the source, resulting in immature
sediments with angular grains and unstable minerals like feldspar (Arkose).
3. What distinguishes a Breccia from a Conglomerate?
A. Mineral composition
B. Clast roundness
C. Degree of sorting
D. Grain size
Answer: B
Conceptual Explanation: Breccias have angular clasts indicating minimal transport, while
conglomerates have rounded clasts indicating significant transport.
4. Which of the following minerals is most resistant to chemical weathering and therefore
most common in mature detrital sedimentary rocks?
A. Olivine
B. Calcium-plagioclase
C. Pyroxene
, D. Quartz
Answer: D
Conceptual Explanation: Quartz is chemically stable at Earth’s surface conditions and
lacks cleavage, making it highly resistant to both chemical and physical weathering.
5. The process of ‘fissility’ is most commonly associated with which sedimentary rock?
A. Shale
B. Siltstone
C. Sandstone
D. Micrite
Answer: A
Conceptual Explanation: Fissility refers to the ability of a rock to split into thin layers, a
characteristic property of shale due to the alignment of clay minerals.
6. In a marine transgression, which vertical sequence of facies would you expect to see from
bottom to top?
A. Limestone, Shale, Sandstone
B. Shale, Sandstone, Limestone
C. Sandstone, Shale, Limestone
D. Limestone, Sandstone, Shale
