ESS 101 B Lab 5 Quiz:
Sedimentary Rocks Questions and
Answers 2026/2027 Solved 100%
Correct
Course
ESS 101
1. What are sedimentary rocks?
Answer: Sedimentary rocks are rocks formed from accumulated sediments that become
compacted and/or cemented, or from minerals precipitated from solution or biological material.
Rationale: Sedimentary rocks commonly form at or near Earth's surface through sediment
deposition, lithification, chemical precipitation, or biological accumulation.
2. What are the three major categories of sedimentary rocks?
Answer: Clastic, chemical, and biochemical sedimentary rocks.
Rationale: Clastic rocks form from fragments of pre-existing rocks, chemical rocks form from
mineral precipitation, and biochemical rocks form through biological activity or accumulated
biological material.
3. What is lithification?
Answer: Lithification is the process by which loose sediment is converted into solid sedimentary
rock.
Rationale: The principal processes involved are compaction and cementation.
4. What is compaction?
Answer: Compaction is the reduction of sediment pore space caused by the pressure of
overlying material.
Rationale: As sediment becomes buried, increasing pressure pushes grains closer together and
reduces the volume of pore spaces.
5. What is cementation?
Answer: Cementation is the process in which minerals precipitate from groundwater and bind
sediment grains together.
Rationale: Common cementing materials include silica, calcium carbonate, and iron oxides.
6. Which characteristic is most important when classifying clastic sedimentary rocks?
,Answer: Grain size.
Rationale: Clastic sedimentary rocks are commonly distinguished by the size of their constituent
particles.
7. What is conglomerate?
Answer: Conglomerate is a coarse-grained clastic sedimentary rock composed primarily of
rounded gravel-sized clasts.
Rationale: Rounded clasts indicate abrasion during transport, while the large grain size indicates
relatively coarse sediment.
8. What is breccia?
Answer: Breccia is a coarse-grained clastic sedimentary rock containing predominantly angular
gravel-sized fragments.
Rationale: The angular shape indicates that the fragments generally experienced less abrasion
and transport than those in conglomerate.
9. What is the difference between conglomerate and breccia?
Answer: Conglomerate contains mostly rounded clasts, whereas breccia contains mostly angular
clasts.
Rationale: Both are coarse clastic rocks, but clast shape distinguishes them.
10. What is sandstone?
Answer: Sandstone is a clastic sedimentary rock composed predominantly of sand-sized
particles.
Rationale: Quartz, feldspar, and rock fragments can make up the sand-sized grains in sandstone.
11. What is shale?
Answer: Shale is a fine-grained clastic sedimentary rock composed mainly of mud-sized
particles and characterized by fissility.
Rationale: Shale commonly splits into thin layers because of the alignment of its fine-grained
particles.
12. What is siltstone?
Answer: Siltstone is a clastic sedimentary rock composed predominantly of silt-sized particles.
Rationale: Its grains are finer than those of sandstone but generally coarser than clay-sized
particles.
, 13. What is the difference between shale and mudstone?
Answer: Shale is typically fissile and splits along thin layers, while mudstone is generally
massive and lacks pronounced fissility.
Rationale: Both contain very fine sediment, but their physical behavior and texture differ.
14. What does grain rounding indicate?
Answer: Grain rounding generally indicates abrasion during transport.
Rationale: Repeated collisions during transportation can wear away sharp edges and corners.
15. What does sediment sorting describe?
Answer: Sorting describes how uniform the sediment grains are in size.
Rationale: Well-sorted sediment contains grains of relatively similar sizes, whereas poorly
sorted sediment contains a wide range of grain sizes.
16. What does well-sorted sediment commonly indicate?
Answer: It commonly indicates prolonged or selective transport and/or repeated reworking.
Rationale: Transport processes can separate grains according to size and density, producing
more uniform sediment.
17. What is cross-bedding?
Answer: Cross-bedding is a sedimentary structure consisting of inclined layers formed as ripples
or dunes migrate.
Rationale: It commonly develops in environments where water or wind transports sediment in a
persistent direction.
18. What do mud cracks indicate?
Answer: Mud cracks indicate that wet, fine-grained sediment was exposed and dried.
Rationale: As water evaporates, clay-rich sediment contracts and develops polygonal cracks.
19. What do symmetric ripple marks commonly indicate?
Answer: Symmetric ripple marks commonly indicate oscillating water movement, such as wave
action.
Rationale: Back-and-forth water motion produces relatively symmetrical ripple profiles.
20. What do asymmetric ripple marks commonly indicate?
Answer: Asymmetric ripples commonly indicate a persistent one-directional current.
Sedimentary Rocks Questions and
Answers 2026/2027 Solved 100%
Correct
Course
ESS 101
1. What are sedimentary rocks?
Answer: Sedimentary rocks are rocks formed from accumulated sediments that become
compacted and/or cemented, or from minerals precipitated from solution or biological material.
Rationale: Sedimentary rocks commonly form at or near Earth's surface through sediment
deposition, lithification, chemical precipitation, or biological accumulation.
2. What are the three major categories of sedimentary rocks?
Answer: Clastic, chemical, and biochemical sedimentary rocks.
Rationale: Clastic rocks form from fragments of pre-existing rocks, chemical rocks form from
mineral precipitation, and biochemical rocks form through biological activity or accumulated
biological material.
3. What is lithification?
Answer: Lithification is the process by which loose sediment is converted into solid sedimentary
rock.
Rationale: The principal processes involved are compaction and cementation.
4. What is compaction?
Answer: Compaction is the reduction of sediment pore space caused by the pressure of
overlying material.
Rationale: As sediment becomes buried, increasing pressure pushes grains closer together and
reduces the volume of pore spaces.
5. What is cementation?
Answer: Cementation is the process in which minerals precipitate from groundwater and bind
sediment grains together.
Rationale: Common cementing materials include silica, calcium carbonate, and iron oxides.
6. Which characteristic is most important when classifying clastic sedimentary rocks?
,Answer: Grain size.
Rationale: Clastic sedimentary rocks are commonly distinguished by the size of their constituent
particles.
7. What is conglomerate?
Answer: Conglomerate is a coarse-grained clastic sedimentary rock composed primarily of
rounded gravel-sized clasts.
Rationale: Rounded clasts indicate abrasion during transport, while the large grain size indicates
relatively coarse sediment.
8. What is breccia?
Answer: Breccia is a coarse-grained clastic sedimentary rock containing predominantly angular
gravel-sized fragments.
Rationale: The angular shape indicates that the fragments generally experienced less abrasion
and transport than those in conglomerate.
9. What is the difference between conglomerate and breccia?
Answer: Conglomerate contains mostly rounded clasts, whereas breccia contains mostly angular
clasts.
Rationale: Both are coarse clastic rocks, but clast shape distinguishes them.
10. What is sandstone?
Answer: Sandstone is a clastic sedimentary rock composed predominantly of sand-sized
particles.
Rationale: Quartz, feldspar, and rock fragments can make up the sand-sized grains in sandstone.
11. What is shale?
Answer: Shale is a fine-grained clastic sedimentary rock composed mainly of mud-sized
particles and characterized by fissility.
Rationale: Shale commonly splits into thin layers because of the alignment of its fine-grained
particles.
12. What is siltstone?
Answer: Siltstone is a clastic sedimentary rock composed predominantly of silt-sized particles.
Rationale: Its grains are finer than those of sandstone but generally coarser than clay-sized
particles.
, 13. What is the difference between shale and mudstone?
Answer: Shale is typically fissile and splits along thin layers, while mudstone is generally
massive and lacks pronounced fissility.
Rationale: Both contain very fine sediment, but their physical behavior and texture differ.
14. What does grain rounding indicate?
Answer: Grain rounding generally indicates abrasion during transport.
Rationale: Repeated collisions during transportation can wear away sharp edges and corners.
15. What does sediment sorting describe?
Answer: Sorting describes how uniform the sediment grains are in size.
Rationale: Well-sorted sediment contains grains of relatively similar sizes, whereas poorly
sorted sediment contains a wide range of grain sizes.
16. What does well-sorted sediment commonly indicate?
Answer: It commonly indicates prolonged or selective transport and/or repeated reworking.
Rationale: Transport processes can separate grains according to size and density, producing
more uniform sediment.
17. What is cross-bedding?
Answer: Cross-bedding is a sedimentary structure consisting of inclined layers formed as ripples
or dunes migrate.
Rationale: It commonly develops in environments where water or wind transports sediment in a
persistent direction.
18. What do mud cracks indicate?
Answer: Mud cracks indicate that wet, fine-grained sediment was exposed and dried.
Rationale: As water evaporates, clay-rich sediment contracts and develops polygonal cracks.
19. What do symmetric ripple marks commonly indicate?
Answer: Symmetric ripple marks commonly indicate oscillating water movement, such as wave
action.
Rationale: Back-and-forth water motion produces relatively symmetrical ripple profiles.
20. What do asymmetric ripple marks commonly indicate?
Answer: Asymmetric ripples commonly indicate a persistent one-directional current.
