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Rocks are any solid mass of mineral
or mineral-like matter occurring
naturally as part of our planet.
Three types of rocks:
1.
2.
3.
Igneous
Sedimentary
Metamorphic
Textbook:
Pgs 70-85
Find and record the
definition of each
TYPE of rock
Formation:
“Mixture of minerals in crystal form and their speed of formation”
Intrusive igneous rocks are formed when magma hardens
beneath Earth’s surface.
Extrusive igneous rocks are formed when lava hardens. This
occurs on the surface of the Earth.
Cooling
Crystallization
Consolidation
Texture:
Fine-grained texture is
caused by rapid cooling
resulting
in
smaller,
interconnected
mineral
grains. EXTRUSIVE
Coarse-grained
texture
is
caused by slow cooling
resulting in larger crystals.
INTRUSIVE
Glassy – no visible crystals
formed EXTRUSIVE
Sedimentary rocks may be made of rock fragments—sediments—or
by chemical reactions.
Sedimentary rocks are products of mechanical and chemical
weathering
They account for about 5% (by volume) of Earth’s outer 10 miles
Contain evidence of past environments
•
Provide information about sediment transport
•
Often contain fossils
Process from an Igneous or Metamorphic rock into Sedimentary rock:
1.
2.
3.
4.
5.
6.
7.
8.
Weathering – mechanical and chemical breakdown of rock to
produce sediments
Erosion – transportation of sediments from one location to
another. Erosion can be a variety of different methods i.e. water,
wind, ice and gravity.
Deposition – ‘drop’ of sediment on a particular area (land or
ocean)
Compaction – The layering of sediments in horizontal ‘bedding’
with gravity to produce sedimentary rock layers
Cementation – the joining with cement of the individual
sediments in the newly formed rock layers.
Lithification – Combination of both compaction and cementation
Burial – sediments are buried on-top of each other over long
periods of time. This is closely linked to deposition
Uplift- Existing rocks are raised up to the surface by force
Rock types are based on the source of the material
Clastic(detrital) rocks – mixture of transported
sediment as solid particles. Particle size is used to
distinguish among the various rock types
Common examples:
- Shale
- Conglomerate
- Sandstone
Chemical rocks – sediment that was once in solution
Common Examples – limestone, coal and rock salt
•
•
•
•
Change of ONE rock INTO ANOTHER rock
Formed by heat and pressure changing existing rocks,
deeper underground than where sedimentary rocks
form; and not too deep to re-melt into magma.
REGIONAL METAMORPHIC affects a large area and
results from plate tectonics
CONTACT METAMORPHISM affects rocks on a
local scale, such as “baking” sedimentary rocks next to
magma or lava
The deeper a rock is within the
Earth, the hotter and denser it is.
Both temperature and pressure
increase with depth. With every
kilometer in depth the
temperature increases by about
25°C (45°F), and the pressure
increases by about 250
atmospheres. (One atmosphere =
14.7 lb/sq in, the average pressure
of the atmosphere at sea level.
2 main types of metamorphic rock:
-
Foliated Metamorphic Rock
Has a banded or layered appearance
-
Non-foliated Metamorphic Rock
Does not have a banded texture
Most metamorphic rocks have the same
overall chemical composition as the
parent rock from which they formed
The rock cycle is a process by
which magma is cooled and
forms igneous rock. The
process continues with the
transition of different types of
rocks on their journey back
into magma inside the Earth’s
interior.
The
rock
cycle
also
includes the following
cycles:
1. Water cycle
2. Plate tectonics
3. Carbon cycle
4. Weather/climate cycles
Lithification –
Solidification/consolidation–
Compaction –
Burial -
Deposition –
Uplift –
Weathering –
Transportation
Crystallization –