22 1 Earth's Structure

22.1 Earth’s Structure

Science of Geology • Geology is the study of the planet Earth • Including: Composition and • Structure

James Hutton • Scottish Physician and Farmer made observation: • Uniformitarianism • Geologic processes that happened in the past also Past operate today • Ex. Mountain building & canyons happened over Present long periods of time

Crust: • Solid layer of the Earth • Forms the upper part of the Lithosphere • The Ocean crust is average 7 km thick • Made up of Dense rock called Basalt • The Continental crust is between 8 and 75 km thick • Made up of Granite rock

Mantle • The layer of the earth below the crust is called mantle • Pressure & Temperature increase at this layer • The mantle is 2800 km thick • Lithosphere-Upper part- cool rigid rock • Asthenosphere-Middle part-Soft flowing rock (similar to taffy) • Mesosphere-Lower part-Stiffer rock

Core • Large Sphere of Metal makes up the center of the Earth • Composition is mostly Iron & Nickel • Pressure is High 3.6 million X that of the Surface • Outer Core = High temp.--Liquid – Magnetic field generated here • Inner Core = Solid—High pressure*-High temperature (5500 deg C)