EESA06H3 Lecture Notes - Lecture 1: Supercontinent Cycle, Tephra, Geologic Time Scale
Document Summary
Lecture 1- how planet earth evolves: continental drift vs plate tectonics. Geologists realized that the earth"s surface is always moving there is no where on the earth"s surface that is stable; it"s on the move horizontally and vertically. It is always rising (vertical) or subsiding (horizontal). In canada, we are moving at about 3. 7 cm per year because the north american continent is being pushed towards the southwest. There are other places on the earth that are moving about 25 cm per year. The number doesn"t sound so big but we have to realize that small changes over long periods does massive alteration of the earth"s surface continents that were once at the arctic could be at the equator for example. Ontario, 400 million years ago was at the equator. Recently, oceans are widening which is called seafloor spreading- progressive widening of the ocean"s basin.
