- After looking at various pieces of evidence such as the aforementioned fossil patterns, mountain formation statistics, and glaciation in the Appalachian Mountains during the Pennsylvanian Period of the Carboniferous Era, he came up with a geological theory that the Earth were made up of plates that moved around thanks to the rotation of the Earth, causing Pangaea to split up - theory was shot down very quickly, as was the idea that America's movement came from the gravitational forces of the sun and the moon. - in 1929, Arthur Holmes came up with a way to explain plate tectonics through mantle convection - causes the plates to move around the Earth on a bed of mantle convection belts - this idea was not paid attention to at the time until the 1960s …show more content…
The inner core is too hot to hold a permanent magnetic field and is slowly becoming thicker as more of the outer core solidifies slowly over time due to the gradual cooling of the Earth.
Chemical Divisions of the Earth's Layers
The Earth's layers are also classified chemically as the Crust, Mantle, Outer Core, and Inner Core.
Crust: the uppermost layer ranging from about 5 km - 70 km in depth. Continental crust is considerably thicker than oceanic crust and is primarily composed of granite and other felsic sodium potassium aluminium silicate rocks, while oceanic crust is thinner and composed mostly of basalt and other mafic iron magnesium silicate igneous rocks.
Mantle: the layer below the crust that is composed of silicate rocks that are richer in iron and magnesium. The boundary between the Crust and the Mantle is the Moho (Mohorovicic discontinuity). Above the Moho are rocks containing plagioclase feldspar, below it are rocks containing no feldspars.
Outer Core: see above
Inner Core: see above
Plates
- Tectonic plates are the pieces of the Earth's crust that "float" on the asthenosphere and make up the