EESA06H3 Final: EESA06 Final Exam Ch2 Summary + 40 MCQ/T or F
Document Summary
Plate tectonics is a theory that suggests earth"s surface is divided into several large plates that change position and size. Plate tectonics combines the concepts of sea-floor spreading and continental drift. Alfred wegener proposed continental drift in the early 1900s. His evidence included coastline fit, similar fossils and rocks in now-separated continents, and paleoclimatic evidence for apparent polar wandering. Wegener proposed that all continents were once joined together in the supercontinent pangea. Wegener"s ideas were not widely accepted until the 1950s, when work in paleomagnetism revived interest in polar wandering. Evidence for continental drift includes careful fits of continental edges and detailed rock matches between now-separated continents. The positions of continents during the past 200 million years have been mapped. Hess"s hypothesis of sea-floor spreading suggests that the sea floor moves away from the ridge crest and toward trenches as a result of mantle convection.