Transcript The Rock Cycle - Mount Mansfield Union High School

NASA video
The Rock Cycle
The three types of rocks
– Igneous
– sedimentary
– Metamorphic
All types of rock are subject to processes that
change one rock type into another.
Igneous Rocks
Formed from cooled and solidified magma
– Intrustive
• formed from the cooling of magma within the earth’s
crust
• Cools and hardens slowly
• Coarse grained- forms large, well-developed crystals
– Extrusive
• melted rock that hardens on the earth’s surface
• Lava cools rapidly
• fine grained rocks
Composition of Igneous Rocks
• Felsic- Rocks in the granite family
– Light colored
– High silica content
– Low magnesium and iron content
•
• Mafic- Rocks in the basalt family
– dark colored
– lower silica content
– high mg and fe content
•
• Andesitic - Medium Silica
– Green, grey, or brown
Sedimentary Rocks
• rock formed from the debris of both other rocks and
living matter.
• 90% of the earth’s crust is made from igneous rock,
but 75% of the world’s land surface is covered with
thin layers of debris or sediments.
• These sediments settle on the beds of oceans, lakes,
and rivers, and recompacted over millions of years to
form sedimentary rock.
How are Sedimentary Rocks Formed?
• DIAGENESIS– the process that turns loose sediments into rock
– COMPACTION• the slow squeezing of sediment to form hard rock
– CEMENTATION• The binding together of compacted sediments by
chemicals like calcite, silica, and iron
3 types of Sedimentary Rock:
– CLASTIC- form from rock fragments weathered
and eroded by glaciers, wind, rivers, and waves.
– ORGANIC- rock made from the remains of plants
and animals
– CHEMICAL- rock made from chemicals dissolved in
water
BEDDING PLANEa boundary between one
layer of sedimentary rock
and another
Metamorphic Rocks
• formed from other rocks as a result of intense
heat, pressure, and chemical processes
– most form deep beneath the surface of the earth
– formed from existing igneous, sedimentary, or
metamorphic rock
Types of metamorphic formation:
• Contact metamorphism:
– when hot magma pushes
through existing rock, changing
the structure and composition
of the rock. Only rocks near the
magma are changed.
• Regional metamorphism:
– movement of one tectonic plate
against another causes heat and
pressure, affecting rocks over an
area of many thousands of
kilometers
Types of metamorphic rocks:
• Foliated:
– show visible parallel bands of minerals ex: slate,
schist
• Unfoliated:
– no bands of crystals ex: quartzite, marble
Interactive animation
• animation