Download Igneous Rocks (Volcanic or Plutonic) Sedimentary Rocks (Clastic or

Igneous Rocks (Volcanic or Plutonic)
Volcanic
- Extrusive
- They cool quickly on the Earth's surface consequently forming small
crystals.
- These crystals are only visible to a microscope.
Plutonic Rocks
- Intrusive
- They cool slowly over a long period of time beneath Earth's surface
forming large interlocking crystals.
-These crystals are visible to the naked eye.
Sedimentary Rocks (Clastic or Non- Clastic)
Clastic
- Are composed of grains or fragments of rocks and minerals that have
been eroded, transported, deposited and cemented or compacted together.
- They are formed from weathering and erosion of igneous, metamorphic or
other sedimentary rocks.
- These rocks are identified by grain size, grain shape and the composition.
Non- Clastic
- Identified according to their grain size, include two main types;
(i) Inorganic
- Rocks from chemicals.
- Composed of minerals that have been precipitated from water (sea water,
fresh water or ground water).
(ii) Organic
- Rocks from living things.
- Composed of fragments of materials from living organisms that are
compacted or cemented together.
Metamorphic Rocks (Contact or Regional)
- Rocks that have been formed by increased in pressure and/or
temperature without melting.
- They were once igneous, sedimentary or even metamorphic rocks.
Contact
- Altered when they come in contact with a heat source.
- Rocks are not good conductors of heat so the main zone of
metamorphism is relatively narrow and occurs in the rock.
Regional
- Occur when rocks undergo increased temperatures and pressures and
are typically associated with the formation of mountain belts along
convergent plate boundaries.