Lecture 5: The Coming of Age of Plate Tectonics Terminology: bathymetry, sounding lines, sonar waves, mid-ocean ridge, mid-Atlantic ridge, North Atlantic plateau, deeps, trenches, pelagic sediment, plankton, oceanic crust, basalt, heat flow, global seismic network, essay in geopoetry, seafloor spreading, Glomar Challenger, Deep Sea Drilling Project, paleomagnetism, normal versus reversed paleomagnetism, paleomagnetic reversal, magnetometer, marine magnetic anomalies, striped seafloor Numbers: none Dates: When did Harry Hess first write the essay in geopoetry? When was the Glomar Challenger first used for ocean drilling? How long ago did the last paleomagnetic reversal take place? How old is the earliest fossil evidence for Homo sapiens? Geography: none Review Questions: Explain the significance of the 1855, 1911, and 1977 bathymetry maps. What do they show, how are they different? How was the lack of sediment in the oceans problematic to oceanographers and geologists at the time? What important correlation was discovered when the navy measured heat flow through the ocean crust? Why is there a global seismic network and what did it contribute to our understanding of how plate tectonics works? What three predictions were made based on Harry Hess’s theory of seafloor spreading and subduction? How did the deep sea drilling project test these predictions? What are the ways in which a cooling lava records the relative direction and orientation of the Earth’s magnetic field What can we say about the effect, magnetic reversal has on the ecology of our planet? How are marine magnetic anomalies evidence for seafloor spreading? Provide three reasons why we no longer use the term continental drift to describe plate tectonics.