Plate Tectonics Liz LaRosa for use with my 5 th Grade Science Class

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 Pangea, Greek for “all Earth” 245 Million years ago Split again – Laurasia & Gondwana 180 million years ago

Evidence of Pangea

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

Bell work p.20 What is the name of the place where two plates meet? Content Goal: To be able to explain the three types of plate boundaries.

2/5 BELL WORK 1.Take out a piece of notebook paper. 2.Put your full name and period in top right corner. 3.Number your paper Skip a line, add number 4 5.Skip 3 lines, add number 5 6.You will have ten minutes to complete pop quiz

Different Types of Boundaries

Divergent Plate Boundaries Plates separate Usually on ocean floor New rocks formed Called rift valley Examples: Mid-Atlantic Ridge, Iceland (above sea level)

Divergent Boundary – Iceland

Iceland rift valley

Progression of Rift Valleys

Divergent Boundary – Oceanic Sea Floor Spreading

Divergent Boundary - Continental

Divergent Boundary – Arabian and African Plates

AFRICAN RIFT VALLEY

Convergent Plate Boundaries Ocean-Continental More dense plate subducts when plates converge Oceanic crust subducts under continental plate Forms volcanic mountain chains to east of subduction Deep earthquakes to the west of subduction

Convergent Boundary – Oceanic & Continental &

Mt Ranier and Crator Lake

Oceanic-Oceanic Convergent Plate Boundaries More dense plate subducts Forms a deep open trench to west of subduction zone Island arcs form 300km to east of subduction zone

Convergent Boundary – Oceanic & Oceanic &

Aleutian Islands in Alaska/Japan/Phillipines

Continental-Continental Convergent Boundaries More dense plate subducts, often both plates are of same density Major mountain ranges form

Convergent Boundaries - Continental &

Great Smoky Mountains/Appalachian Mountains/Rocky Mountains

Convergent Boundary – Indian and Eurasian Plates Himalayan Mountain Range - Mt. Everest

Hot Spots

Transform Boundary – San Andreas Fault

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