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 BoundariesSubduction Zones

Creates trenches in the ocean and mountains and volcanoes on land

Divergent Boundaries

• Tectonic plates move apart

• Causes earthquakes

• Forms Mid Ocean Ridges and Rift Valleys

• East African Rift

• Mid-Atlantic Ridge

Transform Boundaries

• Tectonic plates slide past each

• Forms Fault lines and causes earthquakes

• San Andreas Fault in California

Volcanoes and EarthquakesMost 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