Transcript Plate Tectonics

PLATE TECTONICS
LIZ LAROSA FOR USE WITH MY 5TH GRADE SCIENCE CLASS
HTTP://WWW.MIDDLESCHOOLSCIENCE.COM 2009
EARTH’S LAYERS
The Earth's rocky
outer crust solidified
billions of years ago,
soon after the Earth
formed.
This crust is not a
solid shell; it is broken
up into huge, thick
plates that drift atop
the soft, underlying
mantle.
THE CRUST
• Outermost layer
• 5 – 100 km thick
• Made of Oxygen, Silicon, Aluminum
THE MANTLE
• Layer of Earth between the
crust and the core
• Contains most of the Earth’s
mass
• Has
more magnesium and
less aluminum and silicon
than the crust
• Is denser than the crust
THE CORE
• Below the mantle and to
the center of the Earth
• Believed to be mostly
Iron, smaller amounts of
Nickel, almost no
Oxygen, Silicon,
Aluminum, or Magnesium
TECTONIC PLATES
PLATE TECTONICS
• Greek – “tektonikos” of a builder
• Pieces of the lithosphere that move around
• Each plate has a name
• Fit together like jigsaw puzzles
• Float on top of mantle similar to ice cubes in a bowl of
water
CONTINENTAL DRIFT
Alfred Wegener 1900’s
Continents were once a single
land mass that drifted apart.
Fossils of the same plants and
animals are found on different
continents
Called this supercontinent
Pangaea, Greek for “all Earth”
245 Million years ago
Split again – Laurasia &
Gondwana 180 million years
ago
http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml
EVIDENCE OF PANGEA
SEA FLOOR SPREADING
SEA FLOOR SPREADING
• Mid Ocean Ridges – underwater mountain chains that run
through the Earth’s Basins
• Magma rises to the surface and solidifies and new crust
forms
• Older Crust is pushed
farther away from the ridge
HOW PLATES MOVE
http://pubs.usgs.gov/gip/dynamic/unanswered.html
DIFFERENT TYPES OF BOUNDARIES
http://pubs.usgs.gov/gip/dynamic/understanding.html
DIVERGENT BOUNDARY –
ARABIAN AND AFRICAN PLATES
DIVERGENT BOUNDARY –
ICELAND
http://pubs.usgs.gov/gip/dynamic/understanding.html
DIVERGENT BOUNDARY - OCEANIC
http://www.geology.com
DIVERGENT BOUNDARY - CONTINENTAL
http://www.geology.com
CONVERGENT BOUNDARY – INDIAN AND
EURASIAN PLATES
CONVERGENT BOUNDARY – OCEANIC & CONTINENTAL
http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com
CONVERGENT BOUNDARY – OCEANIC & OCEANIC
http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com
CONVERGENT BOUNDARIES - CONTINENTAL
http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com
TRANSFORM BOUNDARY – SAN ANDREAS FAULT
www.geology.com
REVIEW
• Name the 3 main layers of the Earth
• What is a tectonic plate?
• What was Pangea?
• What is Sea-Floor spreading?
• Name the three different types of plate boundaries and
one location on Earth for each one
REVIEW
• Name the 3 main layers of the Earth
• Crust
• Lithosphere
• Asthenosphere
• Mantle
• Upper mantle (asthenosphere)
• Lower mantle
• Core
• Outer core
• Inner core
REVIEW
• What is a tectonic plate?
• Part of Earth's crust where the
continents and oceans sit upon solid
igneous rock
•
REVIEW
•
What was Pangea?
• “All Earth”
• The large landmass where all the
continents had come together about 245
million years ago
REVIEW
•
What is Sea-Floor spreading?
• the place in the oceanic crust
where the sea floor is being
pushed apart by lava flowing up
from the mantle
REVIEW
•
Name the three different types of plate boundaries and
one location on Earth for each one.
• Convergent boundary – Eurasian and Indian plates
• Divergent boundary – Arabian and African plates and
Iceland
• Transform boundary
- San Andreas Fault in California