What is the Theory of Plate Tectonics?
The earth's crust is made up of plates like a cracked egg that move.
What did Alfred Wegener proposed?
That the continents drifted apart from one large piece of land. (continental drift)
Name the types of evidence and how they supported Wegener theory?
FOSSILS - ocean fossils were found high up in the mountains
GLACIERS- similar marks found in South Africa
COAL - magnetic iron pcs. showed similar directional patterns when the poles shifted.
MOUNTAINS - Similarities in Africa and S. America
ROCKS- striations in the rocks are similar in Africa & S. America.
What is Pangaea?
A large land mass that existed over 200 million years ago that broke off into continents.
What land masses broke off from Pangaea to form South America, Africa, Australia, Antarctica, and India?
What land mass broke off from Pangaea to form North America, Europe and Asia?
What is the Earths crust and the upper portion of the mantle called?
What powers the energy that produces the convection currents?
How do convention currents work?
-Molten rock near the core is heated and becomes less dense and rises.
-Then it cools closer to the surface becoming more dense and sinks. -This causes currents that move the earth's crust.
What is the name of the series of volcanoes that line the outside of the Pacific Plate?
Ring of Fire
The volcanoes that run around the outside of the Pacific Plate are formed by what type of boundaries?
Subduction of Oceanic and Continental Plates.
What causes volcanoes on plate boundaries?
-Subduction of an oceanic plate sliding under a continental plate. -The oceanic crust melts causing heat and a gaseous explosions that escape through the rock.
What type of boundary is the Mid Atlantic Ridge and how does the crust move?
Divergent. They move away from each other.
What plates border the Mid Atlantic Ridge?
North American and Pacific.
What type of boundary moves side by side?
Transformation Fault Boundary
How were the Hawaiian island's formed?
-Volcanoes erupted over a hot spot from heated rock in the mantle. As the Pacific plate moves volcanoes became inactive and close.
-New volcanoes form over the hot spot and create a chain the process repeats.
What is the layer of crust and first part of the upper mantle called?
What is the layer beneath the lithosphere?
Which is more dense oceanic or continental crust?
What mountains were formed by 2 converging plates?
Where do most Earthquakes and Volcanoes occur?
Along plate boundaries.
What is the most dense layer of the earth?
What is convection?
The uneven heating of a liquid or gas.
The scientist that proposed that huge pieces of the earth's crust were moving.
J Tuzo Wilson
The lithosphere is broken up and into huge moving _______________.
What are the forces that set the earth's plates in motion?
The earths core is composed of mostly ___________ , which are__________ and _________.
metals, Iron, nickel
What is the solid portion of the earth is called?
What is the liquid portion of the earth called?
What type of boundary forms between an oceanic and continental plate and how does it form?
Subduction, an oceanic plate (denser) slides underneath a continental plate.
Name a oceanic and continental boundary set of plates.
Nazca and South America
What type of boundary forms between 2 continental plates and how does it form?
Convergence. Plates move towards each other and mix together forming mountains.
Name a set of plates that are formed by 2 continental plates.
Australian Indian and Eurasian.
What type a boundary is formed when 2 plates slip past each other?