ESS 101 B SEDIMENTARY ROCKS: IDENTIFICATION, CLASSIFICATION &
ENVIRONMENTS LAB 5 QUIZ COMPLETE SOLUTION 2026
PART 1 — Rock Identification (20 pts · 4 pts each)
Award full credit for correct rock name + reasonable texture and environment. Accept minor
compositional variations.
Sample Rock Name Texture Composition / Key Depositional
# Minerals Environment
A Shale Fine- Clay minerals (illite, Low-energy: deep
grained kaolinite) marine, lake, tidal flat
clastic
B Sandstone Medium- Quartz, feldspar, rock River channel, beach,
grained fragments dune (aeolian)
clastic
C Conglomerate Coarse- Rounded High-energy: river bar,
grained pebbles/cobbles in alluvial fan
clastic sandy matrix
(rounded)
D Limestone Bioclastic / Calcite (CaCO₃), shell Warm shallow marine
crystalline fragments, fossils (reef, carbonate shelf)
E Rock Salt Crystalline / Halite (NaCl), may Evaporite basin:
(Halite) amorphous include gypsum restricted sea, salt flat
PART 2 — Multiple Choice (15 pts · 3 pts each)
1. C) Sandstone — Sandstone is a clastic sedimentary rock made of sand-sized
(0.0625–2 mm) quartz grains cemented together.
2. B) Diagenesis (lithification) — Diagenesis includes compaction (reducing pore
space) and cementation (minerals precipitate between grains) to form rock.
3. C) Turbidity currents — Turbidity currents are density-driven underwater flows that
deposit coarse grains first, producing characteristic graded beds.
4. C) Rock salt (halite) — Rock salt forms by evaporation of seawater or saline lakes —
a chemical/evaporite sedimentary rock. Breccia, arkose, and graywacke are all clastic.
ENVIRONMENTS LAB 5 QUIZ COMPLETE SOLUTION 2026
PART 1 — Rock Identification (20 pts · 4 pts each)
Award full credit for correct rock name + reasonable texture and environment. Accept minor
compositional variations.
Sample Rock Name Texture Composition / Key Depositional
# Minerals Environment
A Shale Fine- Clay minerals (illite, Low-energy: deep
grained kaolinite) marine, lake, tidal flat
clastic
B Sandstone Medium- Quartz, feldspar, rock River channel, beach,
grained fragments dune (aeolian)
clastic
C Conglomerate Coarse- Rounded High-energy: river bar,
grained pebbles/cobbles in alluvial fan
clastic sandy matrix
(rounded)
D Limestone Bioclastic / Calcite (CaCO₃), shell Warm shallow marine
crystalline fragments, fossils (reef, carbonate shelf)
E Rock Salt Crystalline / Halite (NaCl), may Evaporite basin:
(Halite) amorphous include gypsum restricted sea, salt flat
PART 2 — Multiple Choice (15 pts · 3 pts each)
1. C) Sandstone — Sandstone is a clastic sedimentary rock made of sand-sized
(0.0625–2 mm) quartz grains cemented together.
2. B) Diagenesis (lithification) — Diagenesis includes compaction (reducing pore
space) and cementation (minerals precipitate between grains) to form rock.
3. C) Turbidity currents — Turbidity currents are density-driven underwater flows that
deposit coarse grains first, producing characteristic graded beds.
4. C) Rock salt (halite) — Rock salt forms by evaporation of seawater or saline lakes —
a chemical/evaporite sedimentary rock. Breccia, arkose, and graywacke are all clastic.
