Classification Of Sedimentary Rocks Flashcards
1
Q
Breccia
A
- Rudaceous (>2mm clasts)
- Sub-angular to angular clasts
2
Q
Conglomerate
A
- Rudaceous (>2mm clasts)
- Sub-rounded to rounded clasts
3
Q
Sandstones
A
- Arenaceous (0.0625-2mm clasts)
- Consist of mainly quartz
- Well rounded and well sorted
4
Q
Orthoquartzite
A
- Arenaceous (0.0625-2mm clasts)
- Consists entirely of quartz, including quartz matrix
- ~1mm clasts
- Well sorted and rounded
5
Q
Desert Sandstone
A
- Arenaceous (0.0625-2mm clasts)
- Well rounded and sorted
- Iron hematite matrix
- Consists of mainly quartz
6
Q
Arkose
A
- Arenaceous (0.0625-2mm clasts)
- Poorly sorted, sub-angular clasts
- Consists of >25% K feldspar
7
Q
Greywacke
A
- Arenaceous (0.0625-2mm)
- Poorly sorted, angular
- Many rock fragments
- > 15% clay matrix
8
Q
Clay
A
- Argillaceous (<0.0625mm clasts)
- No distinct layers
- Made of clay minerals
- Plastic and mouldable
9
Q
Mudstone
A
- Argillaceous (<0.0625mm clasts)
- Consists of clay minerals, micas and quartz
- No distinct layers
- Not plastic or mouldable
10
Q
Shale
A
- Argillaceous (<0.0625mm clasts)
- Clay minerals, micas and quartz
- Distinct layering, fissile (breaks into layers easily)
- Not plastic or mouldable
11
Q
Limestones
A
- Contain >50% calcium carbonate
- Most are >90% calcium carbonate in the form of calcite
- Can be chemically or biologically formed
- React with hydrochloride acid
- Two planes of cleavage not at right angles
12
Q
Oolitic Limestone
A
- Made up of ooliths (~1mm sized fragments of shell covered in layers of carbonate material
- Chemically formed
13
Q
Fossiliferous limestone
A
- Made of fossils / fossil fragments
- Micrite or sparite cement
- Biologically formed
14
Q
Chalk
A
- Made from coccoliths (skeletons of single-cell algae)
- Pure calcium carbonate
- Biologically formed
15
Q
Oo-
A
- Made of ooliths
