Plate Tectonics

Early Observations Mapmakers Noticed the apparent fit of the continents on either side of the Atlantic Ocean

Alfred Wegener First proposed Continental Drift in 1912 Also proposed there had been a super-continent and super-sea Pangaea and Panthalassa Pangaea “All The Earth” - Greek Broke apart 200 m.y.a. Evidence to support theory Rock Formations Fossils Ancient Climatic

Evidence From Rock Formations Fracturing of large geologic structures Mountain ranges Rocks from Appalachian Mountains in U.S., England, and Europe Age and rock types matched on separate continents Rocks in South America and Africa

Evidence From Rock Formations

Evidence From Fossils Same fossils found on many continents Kannemeyerid and Labyrinthodont Land-dwelling animals Could not swim great distances between continents Mesosaurus Aquatic, but fresh water

Evidence From Fossils

Ancient Climatic Evidence Coal Forms from dead plant on swampy land Deposits found in Antarctica Antarctica once had a warm climate Glaciers Glacial deposits found in Africa, India, Australia, & South America Once were located near the south pole

Ancient Climatic Evidence

Continental Drift

Reasons Wegener’s Theory Was Not Accepted Could not explain what caused the continents to move What force is great enough to move the land? Could not explain how the continents could move Are they just plowing through the stationary ocean floor?

Exploring the Ocean Floor Major strides in technology enabled scientists to map the ocean floor Sonar Used to locate submarines in WWII Also could tell the depth of the ocean Earthquake activity Earth’s magnetic field Theory of Plate Tectonics 1967 Proved Wegener’s Theory

Earth’s Layers

Shield Volcanoes

Composite Volcanoes

Earthquakes

USGS Earthquake

Tsunami Seismic Sea Wave

Tsunami USGS Earthquake Video Before and after

Andes Mountains

Himalayan Mountains

East African Rift Valley

Transform Boundary

Plate Boundaries Oceanic-Oceanic Divergent Oceanic-Oceanic Convergent Oceanic-Continental Convergent Continental -Continental Convergent Transform Mid-Continent Rifting

Oceanic-Oceanic Divergent Boundary

Oceanic-Oceanic Convergent Boundary

Oceanic-Continental Convergent Boundary

Continental-Continental Convergent Boundary

Transform Boundary

Mid-Continent Rifting

Plate Boundaries Visualizations Transform, Divergent, and O-C Convergent C-C Convergent

Convection Currents

Visualization

Hawaiian Islands Kauai volcanoes are inactive No longer above hot spot Kilauea Worlds most active volcano Sits above hot spot

Hawaiian Islands

Mid-Plate Volcanism Visualization

Yellowstone Caldera

Plate Motions Breakup of Pangaea Future predictions