Sedimentary Rocks
Understanding the key characteristics of Sedimentary Rocks.
- Created by: Caitlin
- Created on: 18-05-13 20:17
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- Sedimentary Rocks
- Sandstones
- Orthoquartzite
- Grains 0.0625 - 2mm
- 90-99% Quartz
- Quartz Cement
- White/ Grey Colour
- Well Sorted
- Well Sorted
- Only Stable Minerals Present
- Beach and Shallow Marine Deposits
- Desert Sandstone
- Iron Oxide Coating = Red Colour
- Well Sorted
- Well Rounded
- Medium Grained 1mm
- Millet Seed Sand
- Cemented together by Silica or Iron Minerals
- Arid Environments
- 90%+ Quartz
- Arkose
- Medium to Coarse Grained
- At least 25% K Feldspar
- 50% - 70% Quartz
- Moderately Sorted
- Pink in Colour
- Sub Angular to Sub Rounded Clasts
- Alluvial Fan environments in Arid Areas
- Greywacke
- Coarse Grained
- Dark Coloured
- Poorly Sorted
- Angular to Sub-Angular
- Many Rock Fragments
- 50% Quartz with K Feldspar
- <15% is Clay Matrix
- Forms as Turbidite Deposits
- Show Graded Bedding
- Orthoquartzite
- Limestones
- Oolitic Limestone
- Chemically Formed
- Medium Grained 1mm
- Sub-Sphereical
- Concentric layers of Calcium Carbonate
- Calcite Mud Matrix (Micrite)
- Calcite Cement (Sparite)
- Tropical or Sub-tropical seas
- Non Clastic
- Fossiliferous Limestone
- Biologically Formed
- Bioclastic not clastic
- Mircrite Matrix or Sparite Cement
- Whole Fossils = Low Energy Environment
- Broken Fossils = High Energy Environment
- Forms in a range of Environments
- Bivalve or Gastropod Shells
- Chalk
- Biologically Formed
- Composed of Coccoliths - Skeletons of Algae
- White in Colour = Pure Calcium
- Low Energy Environments
- Deep Water Shelf Environments
- Non Clastic
- Oolitic Limestone
- Mudstone
- Dark Grey in Colour
- Very Fine Grained
- Not Layered
- Does not have Plasticity
- Clay Minerals - Mica and Quartz
- Clastic
- Low Energy Environment
- Clay
- Very Fine Grained
- Very Compact
- 40% Water
- Variety of Colour
- Distinct Bedding Planes
- Higher the Organic Material = Darker Colour
- Plastic
- Low Energy Environment
- Clastic
- Shale
- Fine Grained
- Clastic
- Distinct Layers and Slaty Cleavage
- Fissile - Easily splits along it's layers
- Clay Minerals, Mica and Quartz
- Not Plastic, Hard, Brittle, Impermeable
- Low Energy Environment
- Sandstones
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