The Rock Cycle

1
The Rock Cycle
http//www.learner.org/interactives/rockcycle/
Catherine M.
2
What is the Rock Cycle?

• A group of processes through which Earth
  materials may pass as they are transformed from
  one major rock type to another.

Three Major Rock Types
Sedimentary
Igneous
Metamorphic
3
How does the Rock Cycle Work?

• Uplift and Magma dispersement
• Weathering and Erosion
• Deposition of material
• Sedimentary Rock is created
• Heat Pressure Time Metamorphic Rock
• More Heat Pressure Igneous Rock

http//www.windows.ucar.edu/tour/link/earth/geolo
gy/rock_cycle.html

4
Sedimentary Rock
How is
Formed?
Sedimentary rock is formed when sediment comes
together and bonds either by compaction,
cementation or both. There are three types of
sedimentary rocks Clastic formed by
mechanical weathering debris Chemical formed by
dissolved materials in a solution Organic
accumulation of plant or animal debris Each
type of sedimentary rock has its own distinct
composition, color and texture. Sedimentary rock
is the only place where we find fossils.
Quartz Sandstone
Shelf Shale (Clay)
Limestone (crushed shell)
http//csmres.jmu.edu/geollab/fichter/SedRx/SimpMo
dl.html
5
Sedimentary Rocks
Breccia - Clastic
Coal - Organic
Iron Ore - Chemical
Conglomerate - Clastic
Rock Salt - Chemical
Sandstone - Castic
                                                  
                        
http//geology.com/rocks/sedimentary-rocks.shtml
6
Metamorphic
What is a
rock ?

• Metamorphic rock is any rock that has been
  changed from its original condition by heat,
  pressure and the chemical activity of fluids, as
  in marble and slate.

This change usually occurs under the Earths
surface and when conditions are right, heat and
pressure cause the mineral composition and/or
texture to transform the original rock into a
newly formed rock.
http//www.windows.ucar.edu/tour/link/earth/geolo
gy/meta_intro.html
7
Metamorphism
Contact

• Rocks that are in contact with hot magma or lava
  often become metamorphosed. This is called
  contact metamorphism.
• Contact metamorphism can either happen deep
  underground or at the Earth's surface.
  Underground, hot magma, fills areas within the
  crust large areas are called batholiths. The hot
  magma alters the surrounding rocks. The amount of
  rock that is changed depends on how much magma
  there is producing heat.
• Above ground, lava erupting from a volcano alters
  the rock that it erupts onto.

http//www.windows.ucar.edu/tour/link/earth/geolo
gy/meta_contact.html
8
Metamorphism
Regional

• Sometimes rocks are metamorphosed over large
  areas that are the size of many states or even
  several countries. This is called regional
  metamorphism.
• Pieces of the Earth's surface layer (called the
  lithosphere) crash into each other, rocks are
  squished and changed deep within mountain ranges.
  This type of process happens along convergent
  boundaries.
• One piece of the lithosphere is pulled below
  another and the rocks are altered deep
  underground by the high pressure and temperature.
  This type of process is referred to as
  Subduction.

http//www.windows.ucar.edu/tour/link/earth/geolo
gy/meta_regional.html
9
Metamorphic Rock

• Slate

Gneiss
Marble
Quartzite
Hornfels
Garnet Schist
Schist (Muscovite)
10
Igneous Rock

• Igneous rocks are divided into two groups, based
  on where the rock forms.
• Intrusive igneous rocks are formed inside the
  Earth and extrusive igneous rock are formed when
  they cool on the surface.

http//volcano.und.edu/vwintl/vwintl.html
Soufriere Hills, Montserrat
11
Intrusive Igneous Rock

• Many kilometers below the Earths surface, molten
  rock called magma flows into cracks or
  underground chambers. There, the magma sits,
  cooling very slowly over thousands to millions of
  years. As it cools, elements combine to form
  common silicate minerals, the building blocks of
  igneous rocks. These mineral crystals can grow
  quite large if space allows and can be seen with
  the naked eye.
• There are many different types of intrusive
  igneous rocks but granite is the most common
  type.

http//www.windows.ucar.edu/tour/link/earth/geolo
gy/ig_intrusive.html
12
Intrusive Igneous Rock
Granite
Gabbro
Pegmatite
http//www.beg.utexas.edu/mainweb/publications/gra
phics/granite-400.jpg
http//geology.com/rocks/igneous-rocks.shtml (2)
13
Extrusive
Igneous Rock
The molten rock (magma) erupts or flows above the
surface as lava, and then cools forming rock.
When lava erupts onto the Earth's surface, it
cools quickly. If the lava cools in less than a
day or two, there is no time for elements to form
minerals. Instead, elements are frozen in place
within volcanic glass. Often, lava cools over a
few days to weeks and minerals have enough time
to form but not time to grow into large crystals.
Basalt is the most common type of extrusive
igneous rock and the most common rock type at the
Earth's surface.
Stromboli, Italy
http//www.windows.ucar.edu/tour/link/earth/geolo
gy/ig_extrusive.html
14
Extrusive
Igneous Rock
Basalt
Obsidian
Scoria
Pumice
Welded Tuff
http//geology.com/rocks/igneous-rocks.shtml
15
The Rock Cycle
http//www.msnucleus.org/membership/html/k-6/rc/ro
cks/6/rcr6_2a.html