GEOL 1114 Lecture Notes - Lecture 2: Asthenosphere, Lithosphere, Planetary Differentiation
Document Summary
90% of the atmosphere is below 16 km. Made of layers, troposphere (0-12 km), stratosphere (12-50 km), mesosphere (50-80 km), thermosphere (80 km and up): hydrosphere. Extends from earth"s outermost crust to the core. Formation & evolution of earth: the big bang. Scientists believe this caused the earth to be formed 13. 7 +/- 0. 2 billion years ago: our system formed from solar nebulas clouds. See nebular theory: planetary differentiation homogenous, differentiation due to density, the layered structure of solid planets. Molten rock rose and formed a primitive crust. Gases rose to form a primitive atmosphere. Compositional & mechanical layers: earth"s layered structure. Core (3400 km: lithosphere rigid/brittle outer shell of earth"s crust, asthenosphere below the lithosphere, where change in materials and convection is believed to occur. Craton: composed of shields and stable platforms. The portion of seafloor adjacent to landmasses. Oceanic ridges are the most prominent feature.
