Download Tectonic Plate Boundaries

Our Amazing Planet
Engage Assignment
• Make a 3 slide power point on each of the
three types of plate boundaries
– Convergent boundaries
– Divergent boundaries
– Transform boundaries
• Include the following
• explanation of the type of boundary
• Picture of each type of boundary
• Crustal features that form at each type
of boundary
Planet Earth
• Earth’s Layers
Crust
• Earth’s thin outermost layer.
–Continental Crust (land) - thick low
density rock (granite).
–Oceanic Crust (sea floor) - thin dense
rock (basalt)
Mantle
• Earth’s thickest layer made of dense
iron-rich super heated soft rock.
• Convection currents occur in the Mantle.
Convection Currents
in the Mantle
• Main cause of plate tectonics
• Hot magma rises and cooler magma sinks
(Just like boiling water)
Core
• Earth’s innermost layer made of hot,
dense iron and nickel.
–Outer core - Liquid
–Inner core - Solid
Lithosphere
• Earth’s outermost layer
• Includes the crust and solid upper part
of the mantle.
• Divided into huge pieces called
“Tectonic Plates”.
• Moves around on top of the
asthenosphere - very hot, soft layer of
the mantel.
Earth’s Tectonic Plates
Continental Drift Theory
– Theory that the Earth’s continents move
over time
– Proposed by Alfred Wegener in the early
1900’s
– Evidence of Continental Drift:
• Continents fit together
• Similar fossils records
• Similar rocks and minerals
• Similar rock formations (mountains)
• Similar climatic conditions – Glaciations
Continents Fit Together
South America and Africa
Similar Fossil Records
Other Evidence - Glaciations
Evidence
of the
movement
of massive
ice sheets
(glaciers).
Sea Floor Spreading
• Occurs where tectonic plates spread
apart at Mid Ocean Ridges
• Magma rises from inside the Earth
creating new sea floor.
• New sea floor pushes the existing sea
floor out explaining why continents
move.
–Evidence that supports the theory of
Continental Drift.
Sea Floor Spreading
Mid-Atlantic Ridge
Convection Currents in the
Mantle
Tectonic Plate Boundaries
Convergent Boundaries
• Tectonic plates
collide -
• Forms trenches,
mountains, and
subduction zones
• CTMS – Convergent –
trenches – mountains subduction
Convergent Boundaries
Subduction Zones
Creates trenches in the ocean and
mountains and volcanoes on land
Divergent Boundaries
• Tectonic plates move
apart
• Forms Mid Ocean
Ridges and Rift
Valleys
• East African Rift
• Causes earthquakes
• Mid-Atlantic Ridge
Transform Boundaries
• Tectonic plates slide
past each
• Forms Fault lines and
causes earthquakes
• San Andreas Fault in California
Volcanoes and Earthquakes
Most Occur at Tectonic Plate Boundaries
Hot Spots
• Areas in the middle of tectonic plates
where magma inside the Earth rises
through the crust and forms volcanoes.
Hawaii Islands
Super Volcanoes
• Yellowstone National park
• 3 overlapping calderas underground is
believed to have formed from a hot spot
creating Yellowstone’s “Super Volcano”
Yellowstone