Josh Syre - Pd. 5 ESS - Barnes
Continental and Oceanic Crust
- Continental crust is the layer of igneous, sedimentary, and metamorphic rock that forms the continents and the areas of shallow seabed close to their shores (continental shelves). Consists of GRANITIC ROCK.
- Oceanic crust is the second of Earth's uppermost crusts (more dense than continental). It surfaces in the ocean basins, and is composed mainly of mafic or, sima, which is rich in iron and magnesium. Consists of BASALTIC ROCK.
Topography of Earth's layout (continental crust).
- The lithosphere of Earth comprises the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater. It is a very thin layer, however is more dense than both the oceanic and continental crust.
- The lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle failure.
Topography of lithosphere layers on Earth (tectonic plates).
- The weaker, deepest, and hotter part of the upper mantle. It is involved mainly with plate tectonic movements and isostatic movements (gravitational equilibrium between asthenosphere and lithosphere).
- The Earth's core is a liquid layer about 2,300 km thick. The outer core is mainly composed of iron and nickel that lies above Earth's solid inner core and below its mantle.
- The average magnetic strength in the Earth's outer core was measured to be 2.5 millitesla, 50 times stronger than the magnetic field at the surface.
- The Earth's inner core is the Earth's innermost part and is a primarily solid ball with a radius of about 1,220 km.
- The solidity of the inner core had been difficult to establish because the elastic shear waves that are expected to pass through a solid mass are very weak and difficult for seismographs on the Earth's surface to detect, since they become so attenuated on their way from the inner core to the surface by their passage through the liquid outer core.