plate tectonics

Plate Tectonics:

Plate Tectonics By: Josh Peters

Theory:

Theory Earth’s crust and part of the upper mantel are broken into sections. Invented by Alfred Wegener in 1912 when he proposed the idea of continental drift, JT Wilson came up with the idea plate of tectonics Alfred Wegener JT Wilson

Composition of Plate Tectonic:

Composition of P late Tectonic Made of Earth’s crust and a part of the upper mantle 2 parts combine Lithosphere-usually 100km thick and less dense than Asthenosphere Asthenosphere Plates on the lithosphere float around on the asthenosphere

What?:

What: The theory that the Earth’s crust and upper mantle is broken into plates that float and move around on a layer of the mantle. What?

WHEN?:

WHEN? 200 million years ago the plates changed from Pangaea to modern times Pangaea- super continent

WHERE?:

WHERE? All over the world, mainly in ocean Plates move 1-6 in. per year

What are Earth’s plates?:

What are E arth’s plates? Major plates African Plate Antarctic Plate Indo-Australian Plate, sometimes subdivided into: Indian Plate Australian Plate Eurasian Plate North American Plate South American Plate Pacific Plate Minor plates Arabian Plate Caribbean Plate Juan de Fuca Plate Cocos Plate Nazca Plate Philippine Sea Plate Scotia Plate

WHY?:

WHY? Causes all oceans and mountains, and gives the continents shape Volcanoes Mountain Belts

Plate Boundaries:

Plate Boundaries When 2 plates collide they can interact in many ways Collide, pull apart, or slide by each other Plates moving apart- divergent boundary Plates moving together- Convergent boundary When new crust is added another is sinking it can occur when the seafloor become less dense, cools, then sinks When an ocean plate meet with a less dense continental plate, the ocean plate sinks and forms a subduction zone High temperatures cause subducting slabs to melt and go under plate boundaries and form volcanoes

Plate Boundaries:

Plate Boundaries Plates collide or slide past each other- Transform boundary Plates collide Subduction zone can also form Earthquakes are common, but volcanoes aren't because theirs little subduction Slide past each other Move in opposite directions or in the same direction at different speeds When a plate slips past another suddenly, earthquakes occur

Types of plate boundaries:

Types of plate boundaries When plates pull apart a rift valley forms Where an ocean and continental plate collide, a subduction forms Where 2 continental plates collide a continental collision forms Volcano magma rises then cools and then the ocean plates separate, seafloor spreading occurs

Summary:

Summary Theory- The theory that the Earth’s crust and upper mantle is broken into plates that float and move around on a layer of the mantle. 3 plate boundaries- transform, convergent, and divergent Composition- lithosphere and asthenosphere 4 types of plate boundaries-seafloor spreading, subduction, rift valley, continental collision Where, What ,Why, and When Where- in oceans Why- to give continents shape and make volcanoes What- theory that earth’s crust is made of individual plates When- the plates changed 200 million years ago from Pangaea to modern

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References Science book- page 106 Wikipedia- http://en.wikipedia.org/wiki/Plate_tectonics Other sites http://www.cotf.edu/ete/modules/msese/earthsysflr/plates1.html

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