Notes on Sedementary Rocks
Sedimentary Rocks
Define 2 types of weathering?
• Mechanical: breaking rocks into smaller chunks o Sediment: clasts (particles or sediment)
• Chemical: dissolve mierals or change rock chemistry and make new minerals o Sediment: Ions in solution
Which type would result in a conglomerate?
• Mechanical.
What are the compositions and depositional environments of Coal and Halite?
• Coal: o Comp.: plant material o Dep. Environ.: Swamp
• Halite: o Comp: NaCl o Dep. Environ.: desert, shallow sea
What latitudes did they form in long ago (Cont Drift ex, Lab 10)?
• Coal: Long Ago- 0º equator Now a days- near 30º N
• Halite: Long Ago- 30ºS Now a days- above 0º equator
What is the sed rock category for Halite, what is the rock forming process for this kind of rocks?
• Halite: o Sed. Rock category: Chemical Sed. Rock (classified by composition. Texture- crystalline) o Forming process: crystallization
Name the rocks with large clast sizes forming in a glacier or upper river depositional environment;
• Breccia- Dep.Environ.: Upper River & Glaciers o Clast size: Gravel- angular and poorly sorted
• Conglomerate- Deop.Environ.: upper river o Clasts Size: Gravel- rounded, poorly sorted
Why do they have different textures?
• Conglomerate has much more rounded clasts due to weathering.
• Breccia is angular because of little weathering.
What is the sed rock category, rock forming process for these kinds of rocks?
• Lithification (Compaction or Cementation)
Igneous Rocks
What are aphanitic and phaneritic textures? Generally, what does texture indicate about cooling rate?
• Aphanitic: most minerals in the “matrix” not visible to the naked eye o Texture: small crsytals (can’t see) dull o Cooling: cooled quickly; Extrusive
• Phaneritic: all materials are visible to the naked eye o Texture: large crystals; shiny, sparkly o Cooling: cooled slowly; Intrusive
Know the texture, magma/lava composition, rock forming
Define 2 types of weathering?
• Mechanical: breaking rocks into smaller chunks o Sediment: clasts (particles or sediment)
• Chemical: dissolve mierals or change rock chemistry and make new minerals o Sediment: Ions in solution
Which type would result in a conglomerate?
• Mechanical.
What are the compositions and depositional environments of Coal and Halite?
• Coal: o Comp.: plant material o Dep. Environ.: Swamp
• Halite: o Comp: NaCl o Dep. Environ.: desert, shallow sea
What latitudes did they form in long ago (Cont Drift ex, Lab 10)?
• Coal: Long Ago- 0º equator Now a days- near 30º N
• Halite: Long Ago- 30ºS Now a days- above 0º equator
What is the sed rock category for Halite, what is the rock forming process for this kind of rocks?
• Halite: o Sed. Rock category: Chemical Sed. Rock (classified by composition. Texture- crystalline) o Forming process: crystallization
Name the rocks with large clast sizes forming in a glacier or upper river depositional environment;
• Breccia- Dep.Environ.: Upper River & Glaciers o Clast size: Gravel- angular and poorly sorted
• Conglomerate- Deop.Environ.: upper river o Clasts Size: Gravel- rounded, poorly sorted
Why do they have different textures?
• Conglomerate has much more rounded clasts due to weathering.
• Breccia is angular because of little weathering.
What is the sed rock category, rock forming process for these kinds of rocks?
• Lithification (Compaction or Cementation)
Igneous Rocks
What are aphanitic and phaneritic textures? Generally, what does texture indicate about cooling rate?
• Aphanitic: most minerals in the “matrix” not visible to the naked eye o Texture: small crsytals (can’t see) dull o Cooling: cooled quickly; Extrusive
• Phaneritic: all materials are visible to the naked eye o Texture: large crystals; shiny, sparkly o Cooling: cooled slowly; Intrusive
Know the texture, magma/lava composition, rock forming