GOPH 375 Lecture Notes - Seismogram, Wave Equation, Love Wave
Document Summary
Lithosphere is broken into plates: divergence zone: seafloor spreading, convergence zones: plates collide, transform faults: plates slide past each other. Wegener said that all the continents had once been united in a supercontinent called pangaea; broken apart by continental drift (not wegener) when pangaea existed, the rest of earth"s surface was a giant ocean called panthalassa. Magma is injected into ocean ridges where it"s imprinted by earth"s magnetic field as it cools to form new rock; the sea floor is pulled away from the ocean ridges. When lava cools, it mineralizes with iron in it. When it cools below the curie point the iron is magnetized towards earth"s magnetic field. North pole is regular polarity; south pole is reverse polarity every few years, magnetic poles (north and south) switch (fig 3. 9: ocean basins are young compared to earth because it"s constantly reforming. Oldest seafloor rocks are at the edge of the ocean basins.
