Practical Skills - Sedimentary Rocks Flashcards
How would you describe the texture of a rock?
- granular/clastic
- size - clay, sand, pebble
- shape - rounded to angular
- sorting - poorly sorted to well sorted
- orientation
What would a high energy location contain?
- very fine grain sizes
- very well sorted
- very well rounded
- qtz rich (when further from source)
What are the way-up structures?
- graded bedding - slowing current
- cross bedding - current
- flute clasts - deep water, current eroding the bottom
- desiccation cracks - evaporation of water
- load casts and flame structures - quick deposition of sand on mud
What is Greywake?
-all composition of clasts
What would a low energy location contain?
- larger grain sizes
- poorly sorted
- angular
- more compositionally complex (containing feldspars and clays)
What is orthoquartzite?
-100% quartz
What is Arkose?
30% feldspar and 70% quartz
Where would you find red sandstone?
In a desert environment
Where would you find black shale?
In deep, quiet, anoxic water with partially dissolved pyrite
Where would you find limestone?
shallow, warm marine water
Where would you find a greywake?
Turbidite
Where would you find Arkose?
River
what are the conditions for limestone formation?
marine conditions shallow water clear water warm water well oxygenated
what is a reef and lagoon?
corals stay in place with the rising and falling sea level
can develop into large thickness of limestone
what are the different types of limestone found in a sedimentary environment?
oolitic
bioclastic
chalk
