GEOL107 Lecture Notes - Lecture 21: Convergent Boundary, Mid-Ocean Ridge, Plate Tectonics
15 Nov 2018
School
Department
Course
Professor
Document Summary
Explanation for apparent wandering of earth"s magnetic poles. Measure magnetism that rocks/minerals acquired in past. Key is that geomagnetic poles have either been located near north geographic pole or near south geographic pole (not in between) However, plots of paleomagnetic poles appear to show that poles have. Can explain apparent polar wander by keeping poles fixed, and allowing for movement of continents to move with respect to poles ( drift ) Plate tectonics can be defined as working model based on 2 fundamental principles: Outer shell of earth is divided into series of 12 or so individual lithospheric plates. These plates are in motion with respect to one another (relative motion) and with respect to underlying lower mantle (absolute motion) Plates move at velocities of 2-16 cm/yr as fast as your fingernails grow. Plates move relative to each other (relative motion) in 3 ways: There are 3 types of boundaries associated with these relative motions.
