Rocks and the Rock Cycle - Amazon S3 · 2016. 9. 19. · Rocks and the Rock Cycle The Rock Cycle...
Transcript of Rocks and the Rock Cycle - Amazon S3 · 2016. 9. 19. · Rocks and the Rock Cycle The Rock Cycle...
Rocks and
the Rock Cycle
To get you thinking…
• What natural process
is responsible for the
appearance of these
rocks?
Bell Ringer
Name the 3 types of rock.
Is one type of rock able to change into a
different type of rock?
Rocks and the Rock CycleThree Major Types of Rock
Igneous Rock – formed when lava or magma cools and crystalizes
Sedimentary Rock –formed from cemented sediments as a result from weathering and erosion
Metamorphic Rock –formed from igneous or sedimentary rocks that undergoes tremendous heat and pressure
Rocks and the Rock CycleThe Rock Cycle
Any of the three major types of rock can be changed into another of the three types.
Rock Cycle – the series of processes in which rock forms, changes from one type to another, is destroyed, and forms again by geological processes
Much of the rock in the Earth’s continental crust has probably passed through the rock cycle many times during Earth’s history.
Rocks and the Rock Cycle
Rocks and the Rock Cycle
Rocks and the Rock Cycle
Rocks and the Rock Cycle
Rocks and the Rock Cycle
Rocks and the Rock Cycle
Rocks and the Rock Cycle
Igneous Rock Formation
Igneous rock – form when lava or magma cools and
crystallizes
Magma – molten rock below Earth’s surface
Lava – magma that flows onto Earth’s surface
Igneous Rocks
Magma formation
There are four main factors involved in the formation of
magma.
Temperature – must be high enough to melt rock
Pressure – as pressure increases, the melting point
increases
Water content – changes the melting point of rocks, as
water content increases, the melting point decreases
Mineral content – changes the melting point of rocks
Igneous Rocks
Mineral content
Different minerals have different
melting points.
Rocks rich in iron and
magnesium melt at higher
temperatures
Rocks rich in silicon melt at
lower temperatures
Igneous Rocks
Basalt
Granite
Partial melting
Partial melting – the process whereby some minerals
melt at relatively low temperatures while other
minerals remain solid
This occurs because different minerals have
different melting points (determined by the chemical
composition of the mineral).
When minerals melt, a certain type of magma is
formed.
Igneous Rocks
Partial melting
Igneous Rocks
What can we infer about the melting point of Quartz?
Fractional Crystallization
When magma cools, it crystallizes in the reverse order of
partial melting
Fractional crystallization – the first minerals to
crystallize are the last minerals that melt
When minerals solidify, a certain type of magma is
formed.
Igneous Rocks
Fractional Crystallization
Igneous Rocks
Mineral Composition of Igneous rocks
Intrusive rocks – formed when magma cools and
crystallizes below Earth’s surface
Generally contain larger crystals due to slower
cooling of magma
Intrusive rocks with large crystals are also called
coarse-grained igneous rocks
Igneous Rocks
Intrusive Rocks
Igneous Rocks
Granite Diorite
Mineral Composition of Igneous rocks
Extrusive rock – formed when magma cools and
crystallizes on Earth’s surface
Generally contain smaller crystals due to faster
cooling of magma
Extrusive rocks with small crystals are called fine-
grained igneous rocks.
Igneous Rocks
Extrusive Rocks
Igneous Rocks
Basalt Rhyolite
Mineral Composition of Igneous Rock
There are three families of igneous rock
Felsic rock – igneous rock that is generally light in
color and contains a lot of silica and feldspar
Also called granitic rock
Igneous Rocks
Igneous Rocks
Pumice
Granite
Rhyolite
Mineral Composition of Igneous Rock
Mafic rock – igneous rock that is generally dark in
color and contains a lot of magnesium and iron
Also called basaltic rock
Igneous Rocks
Igneous Rocks
Scoria
Gabbro
Basalt
Mineral Composition of Igneous Rock
Intermediate rock – igneous rock that contains less
silica than felsic rock but more than mafic rock
Igneous Rocks
Igneous Rocks
Obsidian
Andesite
Diorite
Texture
Texture – refers to the size, shape, and distribution
of the crystals or grains that make up a rock
Igneous Rocks
Rhyolite
(fine-grained)Granite
(coarse-grained)
Obsidian
(glassy)
Porphyritic rocks
Porphyritic texture – rock characterized by large,
well-formed crystals surrounded by finer-grained
crystals of the same mineral or different minerals
Igneous Rocks
Diorite Andesite
Vesicular rocks
Vesicular texture – rock characterized by a spongy
appearance
Holes called vesicles are left behind as gases are
trapped in thick magma
Igneous Rocks
Pumice Scoria
End of Igneous Rocks