GEOLOGY 1 Lecture Notes - Lecture 29: Plate Tectonics, Seafloor Spreading, Pattern Recognition
Document Summary
1 mm diameter objects hit the earth once every 30 seconds. Meteoroids 1 gram or more pass through atmosphere to earth"s surface. Speeds of 11 30 km/sec - atmosphere behaves like solid. Frictional resistance of atmosphere melts away exterior, protecting interior - glazed, blackened crust. Dust and ash released into atmosphere, blocking solar radiation (cool) Widespread wild fires (more dust and ash) (cool) If impact into ocean, large amount of water vapor / steam would be released; h2o. + co2 scatters solar radiation and has long residence in atmosphere (warm) Shock would produce nitrogen oxides; combined with water = nitric acid (acid rain) Centuries of observations have concluded that the earth s make-up is not random. Pattern recognition: earthquakes occur where mountains rise & volcanoes explode. Composite of ideas that explain the observed motion of earth s lithosphere thru mechanisms of subduction & sea-floor spreading which generate continents & ocean basins. Plate tectonics can be summarized with 4 concepts:
