Inside the Earth

Layers of the Earth CRUST MANTLE OUTER CORE INNER CORE

Layers of the Earth(p90) CRUST (Lithosphere) –outermost layer –thinnest layer (5-70km thick) –consists of loose rocks & soil –1% of Earth’s mass

2 Types of Crust Continental= dry land Oceanic= ocean floor

Layers of the Earth MANTLE (Asthenosphere) -layer on which pieces of lithosphere move (solid rock that moves) -thickest layer (2900km thick) -66% of earth’s mass

Layers of the Earth CORE –2 parts of the core 1) Outer Core=liquid iron and nickel spinning 2) Inner Core=solid layer of iron and nickel -33% of Earth’s mass

How do we know? Seismic waves produced by earthquakes travel at different speeds through solid rock and liquids

Continental Drift (p95) Theory that continents can drift apart from one another and have done so in the past Pangaea= single landmass

ALFRED WEGENER THEORY OF CONTINENTAL DRIFT Found evidence for PANGAEA and proposed the theory of continental drift.

Continents “fit together” like puzzle pieces

WEGENER’S EVIDENCE Fossil Evidence fossils are remains of living things that lived long ago. similar fossils have been discovered in matching coastlines on different continents.

WEGENER’S EVIDENCE Mountains –Some mountain ranges on different continents seem to match. Ex: ranges in Canada match Norway and Sweden Ex: Appalachian Mtn. match UK mtn

WEGENER’S EVIDENCE Climatic evidence such as glacial deposits in areas that are now close to the Equator

Theory of Plate Tectonics Theory that pieces of lithosphere move around on top of the asthenosphere

How do the plates move? CONVECTION CURRENTS Hot material from deep within the Earth rises while cooler material near the surface sinks

Convection currents

How do we know? Sea-floor spreading =new ocean floor is created as two lithospheric plates pull away from one another.

Seafloor spreading

So the plates move. Now What? As the plates move, they produce changes in Earth’s surface, including volcanoes, earthquakes, mountain ranges, and deep- ocean trenches.

Plate Boundaries The edges of different pieces of The lithosphere meet at lines called plate boundaries

3 Types of Plate Boundaries Divergent Convergent Transform

3 Types of Boundaries Divergent boundary= two plates move apart Magma rises and creates new crust or seafloor Ex: sea-floor spreading or a rift Boundary animation

Divergent Boundaries © All Rights Reserved. Diverging Africa

edge of the Eurasian continent/plate where it drops into a rift valley which lies between the former and the North American tectonic plate.

3 Types of Boundaries Convergent= when two tectonic plates push into one another.

Convergent Boundaries Continental vs. Continental Continental vs. Oceanic Oceanic vs. Oceanic

Continental vs. Continental When two continental crustal plates collide, the continents buckle upward and form mountains. Himalayas- Asia

Continental vs. Oceanic The oceanic plate slides under the continental plate. The continental crust crumbles and forms new mountains or volcanoes. Subduction Zone

Oceanic vs. Continental Ex: Andes mtn in S. America Cascade Mtns. in N. America- Mt. St. HelensMt. St. Helens

Oceanic vs. Oceanic Two oceanic plates collide, one of the oceanic plates slides under the other. oceanic plates slides also called a subduction zone subduction zone

Hawaiian Islands Oceanic vs. Oceanic

Transform boundary When two tectonic plates slide past each other horizontally Produces? Earthquakes

San Andreas Fault

New Madrid Fault

The Plates Move… So what now? Which way? 50 million years