Intro to Physical Geography

The study of rocks and the physical history of the earth. Geology The study of rocks and the physical history of the earth.

Continental Drift 1915 German Scientist Alfred Wegener suggested the theory of Continental Drift Believed that 300 million years ago, all Earth’s land masses collided to form land mass he called Pangaea (“all land”) 200 million years ago, Pangaea broke into pieces, slowly drifting to the positions of the continents today

Pangaea

http://eatrio.net/wp-content/uploads/2013/01/10.-pangea_politik.jpg

Wegener’s Four Proofs https://www.youtube.com/watch?v=_5q8hzF9VVE Video About the 4 Proofs Of Continental Drift

Evidence of Continental Drift South America & Africa seem to fit together

Evidence of Continental Drift Fossils of the same plants and animals on different continents E.g. the Mesosaurus, a reptile which lived in fresh waters - it could not have traveled across the sea.

Evidence of Continental Drift There are mountains and rocks of similar age and structure on both sides of the Atlantic Ocean E.g. The Appalachians (eastern US and Canada) and the Caledonian Mountains in Northern British Isles and Europe

Evidence of Continental Drift Ice sheets covered parts of southern Africa, India, Australia, and South America approx. 250 million years ago but these places are warm today! Coral reefs around Antarctica

An Unbelievable Theory ? Wegener died in 1930 before there was acceptance of his theory He could not explain HOW the continents moved – suggested tidal forces but did not make sense 1960s, Canadian J. Tuzo Wilson helped to bring up theory again Newer technology able to help explain…

What Will the Earth Look Like https://www.youtube.com/watch?v=uGcDed4xVD4 Vide of what the Earth used to look like – and what it will look like in the far future

Pangaea Ultima The world may look like this in another 250 million years

Plate Tectonics Theory Helps to explain most geologic processes States that Earth’s outer shell consists of plates that move causing earthquakes, volcanoes, mountains and the formation of new crust

Plate Tectonics Earth’s outer shell consists of about 20 plates most have both continental & oceanic crust

Plate Tectonics Plates are floating on layer of hot rock - the mantle

Tectonic Video https://www.youtube.com/watch?v=mB2pzhWUaiU Video About Tectonic Plates

Plate Tectonics Don’t entirely understand what makes the plates move Think that unequal distribution of heat within the core of the earths causes convection currents in the mantle that push the plates around

Plate Tectonics When plates are pushed together you could get: A mountain range A volcano New crust An earthquake

The 3 Kinds of Plates Boundaries

1) Divergent Boundaries The plates are moving away from each other Ex: Mid-Atlantic Ridge Explains the hot springs that run through Iceland

2) Convergent Boundaries The plates are pushing toward each other Ex: the boundary between the Eurasian and the Indian plates under the Himalayas

3) Transform Boundary The 2 plates slide past each other Ex: the boundary between the North American plate and the Pacific plate in California

Plate Tectonics Earthquakes, volcanoes and mountain ranges usually follow plate boundaries Earthquake map below

Plate Tectonics Volcanic activity surrounding the Pacific Plate has been labeled the “Pacific Ring of Fire”

Volcanoes Volcanoes can occur when one plate is pushed under another (oceanic plates are heavier and will push up the lighter continental plates)

Volcanoes Canada’s west coast has currently dormant (sleeping) but not extinct (dead) volcanoes

Mountain Ranges Mountains are created when plates push against each other and fold the crust Mountain ranges can also be volcanic in nature

Watching the Himalayas Form https://www.youtube.com/watch?v=HuSHOQ6gv5Y How the Himalayas Were Formed

Canada’s Mountains New West Coast Mountains The Rockies Old East Coast Mountains The Appalachians

Earthquakes Earthquakes happen when 2 plates rub against each other, causing friction

Earthquakes The San Andreas fault is a large crack in the earth's surface where two gigantic plates are sliding past one another (California)

Tsunamis Tsunamis, like the one that hit Japan in March 2011, are caused by underwater earthquakes

Tsunami March, 2011

Tsunami December, 2004

Tsunamis City of Banda Aceh, Indonesia before and after the tsunami in 2004

Tsunamis and Canada Location: West coast of British Columbia Date: March 27, 1964 Description: The strongest North American earthquake of the century, measuring 8.5 on the Richter scale, struck off Anchorage, Alaska. It sent a tsunami travelling at over 700 km an hour hurtling toward the BC coast. The 4.3 m wave destroyed houses and flooded basements in Hot Springs Cove and Bamfield on the coast of Vancouver Island. The wave travelled up Alberni Inlet and flooded town of Port Alberni. Luckily, no one was killed, but damages caused by the wave totaled over $8 million.