EARTH'S LAYERS
SUBJECTS:
~Layers of the Earth
~Oceanic and Continental Crust
~Pangea
~The Continental Drift Theory & Evidence
~Harry Hesses Discovery
~Vocabulary Words
Layers of the Earth
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The earth has 4 layers which are; crust, mantle,
outer core, and inner core!
CRUST: the crust is a thin layer of cool rock home to all life
MANTLE: earth's thickest layer at 1,700 miles thick it is made of hot rock top of the mantle is cool and rigid middle is hot and soft like tar
OUTER CORE: layer of liquid that surrounds the inner core it is a lower temprature and pressure which allows mantle to remain liquid
INNER CORE: a ball of hot solid metal
outer core, and inner core!
CRUST: the crust is a thin layer of cool rock home to all life
MANTLE: earth's thickest layer at 1,700 miles thick it is made of hot rock top of the mantle is cool and rigid middle is hot and soft like tar
OUTER CORE: layer of liquid that surrounds the inner core it is a lower temprature and pressure which allows mantle to remain liquid
INNER CORE: a ball of hot solid metal
Oceanic and Continental Crust
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The two major types of Earth crusts are Oceanic and Continental Crust.
~The Continental Crust includes all the continents and major islands. it is thicker but less dense. It is located above the ocean water.
~The Oceanic Crust includes all the ocean floors. It is thinner but more dense. It is located under the ocean water.
~The Lithosphere is made up of the crust and the top of the mantle. It is also made up of plates. these are called tectonic plates. These are many layers of large and small slabs of rocks. they fit together like a jigsaw puzzle on the surface of the Earth. Most plates have both the Continental and Oceanic Crust.
~The Asthenosphere is the upper part of the mantle and is just below the lithosphere. it is hotter, softer rock, like tar.
Pangea
![Picture](/uploads/1/3/7/4/13742957/1478158.jpg)
Pangea is the joinging of all the continents into a huge supercontinent. It reached from pole to pole and is centered with Africa today.
The Continental Drift Theory
& Evidence
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Continental drift is the idea that Earth continents were once joined in a single landmass (Pangea) and gradually dirfted apart. Alfred Wegener proposed this hypothesis in 1912 known as the continental drift. He found many links, animals, puzzle land, and plants. Fossils of Messosaurus were discoved in both South America and Western Africa. They could only be in both places if the land was once joined. Best evidence came from rocks found in both Brazil and Western Africa. Limestone was found in North Amerca and in the highlands of Scotland.
Harry Hamond Hess
Sea Floor Spreading discovered 1957
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During WWII, Harry Hess maps the ocean floor by using
sonar and discovers it was not flat, but had mountains. It is one of the
greatest discoveries. In 1962 he published his hypothesis about sea floor
spreading finally giving Aflred Wegeners theory of Continental Drift the
mechanism of how the continents move. It was published in the "History of Ocean
Basins".
sonar and discovers it was not flat, but had mountains. It is one of the
greatest discoveries. In 1962 he published his hypothesis about sea floor
spreading finally giving Aflred Wegeners theory of Continental Drift the
mechanism of how the continents move. It was published in the "History of Ocean
Basins".
Vocabulary Words
Ocean Trenches: These are deep canyons in the sea floor where dense oceanic crust is sinking and is being recycled into the asthenosphere
Mid-ocean ridge: Is a huge underwater volcanic mountain range. This is where sea floor spreading occurs. Melted rock rises through cracks along the crust, cools, and forms new oceanic crust. Old crust is pushed away from the mid-ocean ridge to make room for new crust and is slowly spreading apart. These areas are known as spreading centers
Theory of Tectonic Plates: This states that the earth's lithosphere is made up of huge plates that move over the surface of earth
Subduction: This is the process of one plate being pulled under another
Convection: This is a transfer of heat by movement of material
Convection Current: The motion of the hot, soft rock rising, cooling and sinking, then heating up and rising again
Mid-ocean ridge: Is a huge underwater volcanic mountain range. This is where sea floor spreading occurs. Melted rock rises through cracks along the crust, cools, and forms new oceanic crust. Old crust is pushed away from the mid-ocean ridge to make room for new crust and is slowly spreading apart. These areas are known as spreading centers
Theory of Tectonic Plates: This states that the earth's lithosphere is made up of huge plates that move over the surface of earth
Subduction: This is the process of one plate being pulled under another
Convection: This is a transfer of heat by movement of material
Convection Current: The motion of the hot, soft rock rising, cooling and sinking, then heating up and rising again