Internal Structure of the Earth

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@MeticulousWave

Study Notes

The Earth has a liquid outer core and a solid inner core composed of iron (Fe) and nickel (Ni)
The mantle is composed mostly of silicates (Si and O)
The crust is composed of rocks and minerals, with continental crust being low density and oceanic crust being high density

The lithosphere is the solid, rigid, and elastic layer comprising the upper mantle and crust
There are 7 major plates: African, Antarctica, Eurasian, Indo-Australian, North-American, Pacific, and South American plates
Minor plates include the Caribbean, Scotia, Arabian, Indian, Philippine, Juan de Fuca, Cocos, and Nazca plates
The lithosphere floats on the asthenosphere and slides horizontally over it
The asthenosphere is highly viscous, with high pressure and temperature

Alfred Wegener proposed that continents were once a single large landmass (Pangea)
Pangea broke into two smaller supercontinents, which eventually broke into continents
Evidence includes the continental jigsaw puzzle, seafloor spreading, and fossil distribution

Harry Hess proposed that hot, less dense material rises from below the Earth's crust, creating a crack and magma flows out, cools down, and becomes new seafloor

There are 7 major plates that move smoothly at a rate of 1-16 cm/yr
Movement types: convergent, divergent, and transform
Mechanism: convection current
Evidence includes continental fit, similarities between rock layers, mountain ranges, fossils, glacial evidence, coral reefs, and seafloor magnetic stripes

Distribution of volcanoes, earthquakes, epicenters, and mountain ranges are concentrated in specific areas (Circum-Pacific Belt, Mid-Atlantic Belt, and Mid-Continental Belt)

Volcanic belts: regions with high levels of volcanic activity
Mid-Atlantic Ridge: part of the Mid-Atlantic Belt, along divergent plate boundaries, with youngest crust
Pacific Ring of Fire: part of the Circum-Pacific Belt, with 75% of the world's active volcanoes, along transform and convergent plate boundaries
Mediterranean Sea: part of the Mid-Continental Belt, along convergent plate boundaries
Mountain belts: regions with mountain ranges, located along plate boundaries where collision of plates occurs