Download Rocks and The Rock Cycle

transform
boundary
The San Andreas Fault is
undoubtedly the most
famous transform
boundary in the world. To
the west of the fault is the
Pacific plate, which is
moving northwest. To the
east is the North American
Plate, which is moving
southeast.
Photograph by Robert E. Wallace, USGS.
1
A tsunami is formed when continental plates shift
suddenly as it did last December off the coast of
Indonesia. The huge waves killed thousands.
2
collisional
ranges
The Himalayas, the highest
mountains in the world, were
created this way. (In fact,
they're still growing.) So were
the European Alps. Even the
Appalachian Mountains formed
when two land masses came
together.
The Swiss
Alps
The Appalachian’s
Blue Ridge Mts.
3
Hawaiian
Islands
Artist's
conception
of the
movement of
the Pacific
Plate over the
fixed Hawaiian
"Hot Spot,"
illustrating the formation of the Hawaiian RidgeEmperor Seamount Chain.
4
Rocks and
The Rock
Cycle
3 Main Rock Types
Igneous
Sedimentary
Metamorphic
Igneous
EXTRUSIVE
Forms when lava cools
quickly on the Earths
surface
Forms from molten
rock cooling and
solidifying
INTRUSIVE
Magma cools slowly
over millions of years
deep beneath the
surface
IGNEOUS---Extrusive
Little or NO Crystals!
Lava cools on
the surface so
fast minerals
do not get a
chance to form
Extrusive rocks
can be divided
into two
categories
based on color
Dark colors
black-brownred
Light colors
white-graypink
• Basalt
• Obsidian
• Rhyolite
IGNEOUS---Intrusive
Large Interlocking Crystals!!!
Magma cools
slowly over
millions of
years…
LARGE CRYSTALS
FORM
Intrusive rocks
can also be
divided into two
categories based
on color
Dark colors blackbrown-green
Light colors
white-gray-pink
• Gabbro
• Granite
IGNEOUS---Intrusive
Large Interlocking Crystals!
Magma cools
slowly over
millions of
years…
LARGE CRYSTALS
FORM
Intrusive rocks
can also be
divided into two
categories based
on color
Dark colors blackbrown-green
Light colors
white-gray-pink
• Gabbro
• Granite
Intrusive Igneous Rocks
• Formed when magma “inside” the volcano
cools s-l-o-w-l-y
• Forms large grain crystals
Peridotite
Gabbro
Diorite
Granite
Pegmatitie
Extrusive Igneous Rocks
• Formed from lava “exiting” the volcano and
cooling quickly
• Forms fine-grain crystals
Andesite
Rhyolite
Basalt
Obsidian
Pumice
3 Main Rock Types
Igneous
Sedimentary
Metamorphic
How to make a clastic
sedimentary rock
Weathering and
Erosion
Transportation
Compaction and
Cementation
Deposition
Sedimentary
Rock
Sedimentary rocks are divided into
three categories
Chemical
Mechanical
Organic
(Clastic)
(Biologic)
Minerals are dissolved in the water…water is
evaporated off and leaves behind chemical
sedimentary rocks
Examples are Halite,
Limestone and Gypsum
Sedimentary rocks are divided into
three categories
Chemical
Mechanical
(Clastic)
Organic
(Biologic)
Made from eroded fragments
of other rocks
Shale
Microscope grains
of mud cemented
together
Sandstone
Sand grains
cemented together
Conglomerate
Pebble to boulder
size fragments
cemented together
Sedimentary rocks are
divided into three categories
Organic
Mechanical
(Clastic)
Chemical
(Biologic)
Rocks are formed from the
remains of plants and animals
which have hardened
Oil
(animal remains)
Coral
(sea mammals)
Coal
(dead plant material)
Continental environments – alluvial fan
Sedimentary rocks, environments and structures
Continental environments – eolian deposits
Sedimentary rocks, environments and structures
Sedimentary Facies (facies – the character of a rock
defined by its formation, composition and fossil content)
Sedimentary rocks, environments and structures
Transitional environments – deltas
Sedimentary rocks, environments and structures
A bedding plane is the line separating
one layer of compressed rock from the
next layer of compressed rock.
Sedimentary structures – bedding planes
Sedimentary rocks, environments and structures
Sedimentary structures – graded bedding
Sedimentary rocks, environments and structures
Sedimentary structures – graded bedding
Sedimentary rocks, environments and structures
Sedimentary structures – mud cracks
Sedimentary rocks, environments and structures
3 Main Rock Types
Igneous
Sedimentary
Metamorphic
Metamorphic rocks form from
HEAT&PRESSURE
Two types of
metamorphism
Contact
Rock surrounding
a magma body
gets cooked and
changes
Regional
Tectonic forces
Metamorphism
occurs over a
large area
Contact Metamorphism is the
ZONE
_________
of contact where
an Igneous Intrusion meets
the
existing
rock
but
DOES NOT melt it.
________
Contact Metamorphism
Deep underground, zones of metamorphism form around the
hot magma of batholiths.
L.Gardiner/Windows Original
CONTACT METAMORPHISM
Contact metamorphism
occurs only at the place
where the magma contacts rock
SHALE
SANDSTONE
LIMESTONE
SANDSTONE
IGNEOUS
INTRUSION
Regional Metamorphism:
occurs over large areas with
extreme pressures & temperatures
Regional Metamorphism
Tectonic forces smash continents together. The rocks get
heated and become semi-molten. The added pressure causes
the mineral to separate into bands and sometime to even flow
before cooling again!
This extreme heat and
pressure is what builds
MOUNTAINS
PARENT ROCK
Is the rock from which
metamorphic rock is
formed.
Common Metamorphic Rocks
Parent Rock
Metamorphic Rock
Granite (Igneous Intrusive)
Gneiss
Shale (Sedimentary)
Slate
Sandstone (Sedimentary)
Quartzite
Parent Rock
Metamorphic Rock
Limestone (sedimentary)
Marble
Extrusive Igneous
A Metamorphic rock is one whose original form has
been changed by heat and pressure.
This change is called re-crystallization. These
changes are
not caused by melting.
If the rock melted and cooled it would be an Igneous
Rock.
Changes caused by re-crystallization may include the
creation and growth of new mineral crystals.
Rocks which are intensely compressed (pressure) can
also become metamorphic. Becomes more dense and
resistant to weathering
The growth of new minerals may cause the rock to
appear banded or foliated stripes of light and dark
minerals.
SCHIST
SHOWS
BANDING
pressure
pressure
pressure
DISTORT
It can also ____________
(BEND) OR
DESTROY
______________
ORIGINAL STRUCTURES
The Rock Cycle
48
49
Tectonic Forces: Intrusive Landforms
Batholith
Laccolith
Sill
Dyke
Mesa’s & Buttes
Constructing a Rock Cycle
Melts
at high
temp
MAGMA (Molten Rock)
Metamorphic
Cools &
Crystalises
Igneous
Weathers
& Erodes
Extreme Heat & Pressure
Sedimentary
Sediment
Compressed and compact