EARTH 222 Lecture Notes - Lecture 3: Continental Drift, Continental Crust, Seafloor Spreading
Document Summary
Early speculation of continental motion: during the 16th century davinci and ortelius noticed the continents fit together esp. South america and africa: antonio snider pellegrini published an early map of how the two might fit together in. Initiated 100 year scientific process from hypothesis to well tested theory: observation - hypothesis - testing - theory (scientific method) Evidence for continental drift (wegener looked at this: continents seem to fit into one giant landmass. Either continents were joined into pangaea or mesosaurus could build boats. 2b paleontological evidence for glossopteris flora in s. america, africa, antarctica, asia and australia. would not find this today: glacial deposits and striations on continents from 250 to 220 ma consistent with joined continents. caused by glaciers - not there anymore but we interpret the lines as the flow of the glacier because it scrapes in the direction of motion. Must have been at a high latitude before.