ESS105H1 Lecture 2: Continental Shift and Plate Tectonics
Document Summary
Ess lecture #2: continental shift and plate tectonics. Physical laws operating today also operated in the past. 4 lines of evidence to support this side: puzzle - like t of continents, fossil distributions, mountain belt match ups, premian glacial distribution. Observation: shapes of continents match across atlantic ocean. Plate tectonics is the unifying theory in geology that explains how the movement of tectonic plates are related to geological features. Single tectonic plate may include all or part of continent and part of ocean basin. Edge of plate, where it is in contact with another plate. Tectonic plates are made of rigid lithosphere and they glide over the weaker asthenosphere. Oceanic plates move apart at mid-ocean ridges (sea oor spreading) Narrow trough or rift, magma rises through fractures, asthenosphere rises and melts. Black smokers: hot springs that carry dissolved metals. Can lead to sea oor spreading and new basin forming plate boundaries. Is created at spreading centres (divergent plate boundaries)
