GEO 1111 Lecture Notes - Lecture 9: Passive Margin, Aseismic Creep, Thermal Subsidence

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: Donald Cummings

Document Summary

Lec 9 - earth"s interior & plate tectonics. How is heat transferred from inside the earth : Conduction : heat energy transmitted through solid by molecular vibrations , slow. Convection : heat energy transmitted by density-driven fluid motion set up by the temperature gradient , fast. Viscoelastic (share both solid and fluid like properties) Postglacial rebound : proves the mantle flows like a fluid. From rebound rate : viscosity (resistance to flow) of the mantle can be calculated. Convecting : because it has a very high rayleigh number. Rayleigh number : indicates whether or not convection will occur in a fluid that is being heated from below. Problems with thermal-convection driven model of plate tectonic. Plates vary significantly in size, so regular convection cells not possible. Convection cells in mantle should be stable long term features, but spreading ridges move rapidly over earth"s surface, indicating they are superficial features.